Archivo Digital UPM - Archivo Digital...

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ACKNOWLEDGEMENTS!!!I!would!like!to!thank!Professor!Joaquín!OrdieresCMeré,!who!tutored!me!during!this!project!and!who!gave!me!this!project!when!I!was!desperately!looking!for!one.!Thank!you!for!your!help!in!every! way,! from! taking! the! time! to! teach!me! about! Microsoft!Word! to! your! quick! replies,!sometimes!even!from!Holland.!It!was!very!inspiring!to!come!across!such!a!devoted!teacher.!!!I!would!also!like!to!thank!Ms.!Bing!Gong,!whom!I!worked!with.!Thanks!for!sharing!so!much!information,!knowledge!and!experience!with!me!and!answering!all!of!my!many!questions.!!!Thank!you!both!for!your!help!and!patience!with!me.!It!was!a!pleasure!to!work!with!you.!!!I!would!also!like!to!thank!all!the!Institutions!that!made!it!possible!for!us!to!get!the!necessary!data!for!this!study.!Notably!to!the!Sistema!de!Información!Medioambiental!of!the!Community!of!Madrid,!who!helped!me!manage!the!air!quality!data!available!for!download!on!their!website!but!also!who!provided!me!with! the!meteorological!data!collected! from! the!network!of! fixed!monitoring!stations,!though!this!data!is!usually!not!public.!!!Also!a!special!thanks!to!the!whole!Dirección!General!de!Coordinación!de!la!Asistencia!Sanitria!of! the! Community! of! Madrid,! and! particularly! to! the! Deputy!Manager! of! the! Coordinación!Asistencial,! Rodolfo! Antuña,! who! took! the! time! to! meet! with! me! and! after! some! intense!insisting!from!my!part,!went!out!of!his!way!to!provide!us!with!the!ICDs!hospital!admissions.!Thanks!also!to!Julia!Rubio!Flores,!who!sent!me!the!actual!data.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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RESUMEN!!!

Introducción++!Numerosos!estudios!epidemiológicos!han!demostrado!la!relación!entre!la!contaminación!del!aire!y!la!mortalidad!y!morbosidad!del!ser!humano.!En!Europa!se!estima!que!la!contaminación!es!la!causa!de!un!6%!de!las!muertes.!Aunque!intuitivamente!la!contaminación!se!relacione!principalmente!con!enfermedades!del!aparato! respiratorio!como!el!asma!o! la!bronquitis,! la!literatura! disponible! demuestra! que! la! contaminación! influye! en! otros! diagnósticos! como!enfermedades! cardiovasculares,! enfermedades! del! aparato! circulatorio! e! incluso! en!problemas!del!sistema!nervioso.!Por! lo! tanto,! resulta!evidente!que! la!contaminación!es!un!problema! latente! para! la! salud! pública.! Esto! hace! que! la! disminución! de! los! niveles! de!contaminación!y!la!mejora!de!la!calidad!del!aire!sean!objetivos!presentes!en!la!legislación.!!!Si!bien!hay!más!de!180!contaminantes!del!aire!que!la!Agencia!de!Protección!Medioambiental!(EPA)! de! los! Estados! Unidos! controla,! esta! define! únicamente! 6! como! contaminantes!comunes:! ozono! (O3),!monóxido! de! carbono! (CO),! dióxido! de! sulfuro! (SO2),! partículas! en!suspensión!(PM)!C!que!reúnen!partículas!de!diámetro!inferior!a!2,5!µm!(PM2,5)!y!partículas!de!diámetro!entre!2,5!y!10!µm!(PM10),!óxidos!de!nitrógeno!(NOX)!y!plomo!(Pb).!!Efectivamente,!las!leyes!medioambientales!tanto!europeas!como!estadounidenses!se!centran!en!el!control!de!estos!contaminantes!de!manera!bastante!similar:!el!gobierno!central!marca!unos!límites!de!concentración!de!contaminantes!en!el!aire!y!los!diferentes!estados!son!libres!de!elegir!e!implantar!las!medidas!que!consideren!apropiadas,!siempre!y!cuando!les!permitan!alcanzar!dichos!limites!en!un!tiempo!determinado.!!!El! análisis!de! la! legislación! sobre! calidad!del! aire! sitúa!al! tráfico! como!principal! fuente!de!contaminación!en!medios!urbanos!y!por!lo!tanto!gran!parte!de!las!medidas!se!concentran!en!este!ámbito.!Las!soluciones!propuestas!pasan!por!!innovaciones!técnicas!y!tecnológicas,!cuyo!efecto!es!a! largo!plazo,!como!por!medidas!que!pretenden!conseguir!efectos!a!corto!plazo,!que!suelen!basarse!en!un!cambio!de!comportamiento!de!los!individuos.!Ejemplos!de!estas!últimas! medidas! son! el! fomento! del! uso! de! transporte! público! o! de! alternativas! al!desplazamiento!en!vehículos!de!combustión.!Para!ser!eficaces,!las!medidas!que!dependen!del!comportamiento!del!individuo!exigen!una!cierta!concienciación!social.!!!En!Madrid,!estas!medidas!pueden!verse!en!la!implementación!del!transporte!compartido:!la!capital!se!ha!sumado!a!la!iniciativa!europea!de!car2go!además!de!haber!implantado!una!flota!de!bicicletas!compartidas,!BiciMad.!Pese!a!todo,!la!contaminación!del!aire!ha!sido!un!tema!particularmente! polémico! en! los! últimos! meses.! La! concentración! de! NOX! sobrepasó! los!límites!establecidos!por!la!ley!y!se!llevaron!a!cabo!medidas!de!restricción!de!circulación.!!Para!afrontar!con!éxito!la!crisis!de!contaminación!urbana!es!necesario!realizar!un!estudio!de!mayor!profundidad!que!relacione!todos!los!aspectos!del!problema:!!la!evaluación!de!la!calidad!del!aire,!los!efectos!de!la!contaminación!en!la!salud!pública!y!la!concienciación!social.!Por!lo!ya!expuesto,!parece!que!Madrid!podría!beneficiarse!de!un!estudio!de!esta!naturaleza.!!!

Estudio+de+la+literatura++!En! la! literatura! actual! existen! estudios! que! exploran! todas! las! relaciones! bilaterales! entre!contaminación,! sus! impactos! sobre! salud! y! concienciación! social! de! la! contaminación.! A!continuación!se!destacan!las!ideas!principales!expuestas!en!ellos.!!!En!la!mayoría!de!los!estudios,!la!monitorización!de!los!contaminantes!se!realiza!a!través!de!redes! de! estaciones! de! monitorización! fijas! que! producen! resultados! estáticos.! Estas!

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estaciones! suelen! ser! caras! y! por! lo! tanto! pocas! y! dispersas,! por! lo! que! sus!medidas! se!extrapolan!a!otras!áreas!para!medir! la!exposición!a! la!contaminación!en! todos! los!puntosf!haciéndose!muchas!veces!sin!tener!en!cuenta!los!procesos!meteorológicos!que!afectan!a!la!dispersión!de!contaminantes.!Además,!la!exposición!individual!obtenida!mediante!el!enfoque!estático! asume! que! el! individuo! permanece! en! casa.! Las! últimas! tendencias! emplean! un!enfoque! dinámico,! apoyándose! en! novedades! tecnológicas! como! el! uso! de! estaciones!móviles!con!micro!sensores!o!la!localización!de!individuos!por!GPS!o!por!el!registro!que!su!móvil!deja!en!las!células!de!red.!Así!mejora!la!medida!de!exposición!individual,!adecuando!los!niveles!de!contaminación!a!la!localización!real!y!variable!del!individuo!a!lo!largo!del!día.!!!Con! medidas! de! exposición! individuales! más! realistas,! los! resultados! de! los! estudios!epidemiológicos!serían!mucho!más!precisos!y! las!medidas!establecidas!por! los!gobiernos!más!adaptadas.!Sin!embargo,!el!problema!de!la!contaminación!depende!enormemente!de!la!concienciación!social!del!individuo!y!de!su!(re)acción!cívica.!En!este!ámbito,!los!estudios!han!encontrado!una!laguna!entre!el!riesgo!real!y!latente!de!la!contaminación!y!su!percepción.!No!obstante,!los!estudios!más!recientes!indican!un!cambio!de!rumbo!en!lo!que!a!concienciación!social!sobre!los!problemas!medioambientales!se!refiere,!incluyendo!el!de!la!contaminación.!!!Además,!debido!a!la!ubicuidad!de!las!redes!sociales!en!el!día!a!día!de!la!sociedad,!estas!se!han!situado!como!una!de!las!herramientas!sociales!de!mayor!poder!siendo!lugar!de!debate!social! y! de! quejas.! Algunos! estudios! pilotos! de! contaminación! han! utilizado! información!extraída!de!las!redes!sociales:!se!ha!relacionado!con!éxito!la!variación!del!volumen!diario!de!mensajes!vinculados!con!la!contaminación!con!la!variación!diaria!real!del!nivel!de!calidad!de!aire! en! Pekín,! por! ejemplo.! Además,! utilizar! las! redes! sociales! como! indicador! de! la!concienciación! social! soluciona! el! problema! de! parcialidad! que! presentaban! los! métodos!tradicionales!de!medida!de!concienciación!social!como!las!encuestas!o!entrevistas.!!!

Objetivos++!Hasta!ahora,!no!existe!ningún!estudio!que!relacione!explícitamente!datos!de!contaminación,!salud! pública! y! concienciación! social! sobre! ambos.! Por! lo! tanto,! por! los! beneficios! ya!expuestos!que!un!estudio!así!aportaría,!este!estudio!se!plantea!dos!objetivos!principales.!!!

1.! Enriquecer! la! evidencia! empírica! existente! en! la! literatura! sobre! las! relaciones!bilaterales!entre!los!conceptos!discutidos:!!(i)! A!mayor!contaminación,!mayor!impacto!sobre!la!salud!pública!(ii)! A!mayor!contaminación,!mayor!concienciación!social!!(iii)! A! mayor! impacto! de! la! contaminación! sobre! la! salud! pública,! mayor!

concienciación!social.!!!

2.! Proporcionar! una! herramienta! de! predicción! del! número! de! ingresos! hospitalarios!utilizando! como! variables! de! entrada! datos! heterogéneos,! incluyendo! datos! de!contaminación,! variables! meteorológicas,! calendario! laboral,! ingresos! hospitalarios!pasados!y!comentarios!en!redes!sociales!relativos!a!la!contaminación!y!sus!síntomas.!Esta!herramienta!pretende!mejorar!la!gestión!de!los!recursos!de!la!salud!pública.!!

!Metodología++

!Selección!!y!obtención!de!datos!!

Para! cumplir! con! los! objetivos! planteados,! este! estudio! combina! datos! de! fuentes!heterogéneas!que!cubren!el!área!municipal!de!Madrid!obtenidos!a!lo!largo!de!2014!y!2015.!!!La!contaminación!se!mide!a!través!de!la!concentración!de!contaminantes!en!el!aire,!medidos!por! las! estaciones! de! monitorización! del! Ayuntamiento! de! Madrid.! Estas! 24! estaciones!proporcionan!medidas!horarias!de!alguno!o!de!la!totalidad!de!los!siguientes!contaminantes:!!

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O3,! SO2,! NOX,! PM2,5,! PM10,! CO,! benceno,! tolueno,! etilbenceno,! hidrocarburos! totales! e!hidrocarburos!excluyendo!al!metano.!!La!influencia!de!fenómenos!meteorológicos!en!los!procesos!de!dispersión!de!la!contaminación!se!miden! a! través! de! las! siguientes! variables:! temperatura,! humedad! relativa,! dirección! y!velocidad!del!viento,!presión,!precipitaciones!y!radiaciones!solar!y!ultravioleta.!Estos!datos!provienen!de!las!mismas!estaciones!de!monitorización!de!contaminantes!y!de!dos!estaciones!suplementarias!gestionadas!por!la!Agencia!Estatal!de!Meteorología!(AEMET).!!!El!impacto!de!la!contaminación!sobre!la!salud!pública!se!mide!a!través!del!número!de!ingresos!hospitalarios!diarios!en!hospitales!del!municipio!de!Madrid!por!diagnósticos!que!la!literatura!ha! demostrado! están! relacionados! con! la! contaminación,! recogidos! en! la! ¡Error!+ No+ se+encuentra+el+origen+de+la+referencia..!!!

Código+CIE+ Diagnóstico+correspondiente+460!a!519! Enfermedades!del!Aparato!Respiratorio!

410!a!417,!420!a!438!y!440!a!444! Enfermedades!cardiovasculares!493! Asma!428! Paro!cardiaco!

410!a!414! Cardiopatía!isquémica!430!a!438! Enfermedades!cerebrovasculares!390!a!459! Enfermedades!del!aparato!circulatorio!

! Mortalidad!! Número!total!de!admisiones!

Tabla!1!Diagnósticos!seleccionados!según!su!codificación!CIE!!La!concienciación!social!se!mide!a!través!de!mensajes!publicados!en! la!red!social!Twitter.!Para!ello!se!han!seleccionado!ciertas!palabras!clave!en!relación!con!la!contaminación!y!sus!efectos!en!la!salud!y!se!han!recogido!los!tweets!que!las!contenían!a!través!de!un!software!de!webCscraping!desarrollado!por!el!profesor!Joaquín!OrdieresCMeré!para!este!proyecto.!!!

Técnicas!empleadas!El! primer! objetivo! planteado!pretende!encontrar! relaciones! entre! grupos! de! dos! variables.!Teniendo!en!cuenta!que!por!su!naturaleza!la!relación!entre!las!variables!no!tiene!porqué!ser!inmediata,!se!utiliza!la!función!de!correlación!cruzada!(CCF)!que!encuentra!la!relación!entre!dos!variables!dependientes!del!tiempo!yt!y!xt+h.!En!este!caso,!se!busca!encontrar!el!valor!de!h!tal!que!la!correlación!R!entre!ambas!variables!sea!máxima.!Si!h!es!positivo,!yt!provoca!xt+hf!un!h!negativo!indica!que!yt!es!una!consecuencia!de!xt+h.!Según!los!valores!y!signos!de!las!correlaciones,!se!establecerá!si!efectivamente!este!estudio!permite!añadir!evidencia!al!trabajo!empírico!disponible!en!la!literatura.!!!El! segundo! objetivo! pretende! estimar! el! valor! de! ingresos! hospitalarios! yt! a! partir! de! una!selección!de!variables!de!entrada!según!los!resultados!del!análisis!CCF!y!evaluadas!en!t+h.!Para!construir!un!modelo!cuyo!output!sea!el!valor!diario!de!ingresos!hospitalarios,!se!emplean!técnicas!de!aprendizaje!supervisado!de!la!minería!de!datos:!regresión!lineal!(MLR),!máquinas!de! soporte! vectorial! (SVM),! redes! neuronales! artificiales! (ANN),! aprendizaje! basado! en!árboles! de! decisión! (CART),! selvas! aleatorias! (RF)! y! técnicas! de! remuestreo! basadas! en!árboles!de!decisión!(GBM!y!BaggedCART).!!Estas! técnicas! o! algoritmos! construyen! modelos! a! partir! de! un! conjunto! de! datos! de!entrenamiento.!Los!modelos!creados!deben!evaluarse!mediante! la!medición!de! los!errores!que!se!generan!cuando!se!les!somete!a!la!predicción!de!un!conjunto!de!datos!de!evaluación.!Se!elige!el!modelo!que!menor!error!presente.!!Además,!el!modelo!puede!mejorarse!gracias!al!análisis!de!la!importancia!de!las!variables!de!entrada.!Tras!este!análisis!puede!variarse!la!

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selección! de! variables! de! entrada! para! comparar! los! errores! del! nuevo!modelo! de!menor!número!de!variables!de!entrada!con!el!modelo!anterior.!De!esta!manera!se!logra!alcanzar!el!modelo!con!mayor!precisión!de!predicción!y!mayor!simplicidad.!!!

Resultados+!Los!resultados!de!los!análisis!CCF!llevados!a!cabo!se!muestran!en!la!Tabla!2,!que!incluye!el!valor!del!mejor!coeficiente!de!correlación!y!su!retraso!h!correspondiente.!Cabe!destacar!que!los!resultados!expuestos!en!este!documento!solo!incluyen!aquellas!parejas!de!variables!que!presentaban!correlaciones!superiores!a!0,1.!Además,!puesto!que!el!segundo!objetivo!de!este!estudio!es!la!obtención!de!un!modelo!de!predicción!para!!la!variable!ingresos!hospitalarios,!en! las! correlaciones!que! impliquen!a! la! ! salud!pública,! esta! será! la! única! variable!que! se!analizará.!!!Los! resultados! del! CCF!muestran! en! todos! los! casos! correlaciones! débiles! pero! aun! así!existentes.!Sin!embargo,!los!signos!negativos!de!los!coeficientes!de!correlación!!indican!unas!relaciones! en! sentido! opuesto! al! establecido! en! las! hipótesis! (i)! e! (ii).! Dicho! esto,! los!resultados!del!estudio!entre! tweets!publicados!que!contienen!palabras! relacionadas!con! la!contaminación! e! ingresos! hospitalarios! presentan! valores! del! coeficiente! de! correlación!positivos,!por!lo!que!podría!sustentarse!la!hipótesis!(iii)!a!mayor!impacto!de!la!contaminación!sobre!la!salud!pública,!mayor!concienciación!social.!!!!

xt+h% Coeficiente+de+correlación+

Retraso+h+(días)++

xt+h% Coeficiente+de+correlación+

Retraso+h+(días)++

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yt=!!ingresos!hospitalarios!ingresos!hospt!

0,822731! C7!! Pressure! C0,10073! C2!

O3! C0,18123! C14! tos! 0,192473! C8!PM2,5! C0,15575! C9! garganta! 0,175398! C15!PM10! C0,20355! C9! contaminación!! 0,159941! C14!NO2! ! C14! respiración!! 0,134284! C8!!SO2! ! C13! air! 0,186789! C15!

Temperature! C0,17758! C24! sick! 0,134173! C2!Humidity! 0,156952! C20! ! ! !

! ! ! ! ! !yt=!tos! yt=!air!

O3! C0,15! C19! PM2,5! C0,15! 0!PM10! C0,2! 0! ! ! !

Tabla&2&Resultados&de&los&análisis&de&CCF&para&todas&las&variables&estudiadas&&

Si!bien!ninguno!de!los!resultados!del!análisis!CCF!lleva!a!relaciones!fuertes!entre!parejas!de!variables,!estos!resultados!sirven!de!base!para!la!elaboración!de!un!modelo!de!predicción!de!los! ingresos! hospitalarios! diarios.! Efectivamente,! algunas! de! las! variables! estudiadas!presentan! correlaciones!débiles! pero! adelantadas!al! número!de! ingresos!hospitalarios.! La!realización!de!la!autocorrelación!de!la!variable!ingresos!hospitalarios!muestra!que!la!variable!está!explicada!en!un!82%!de!los!casos!por!el!día!de!la!semana.!Sin!embargo,!el!18%!restante!puede!ser!explicado!mediante!la!introducción!de!variables!de!entrada!adicionales.!!!En! efecto,! una! vez! seleccionadas! las! variables! de! entrada,! los! datos! se! someten! a! las!diferentes! técnicas! de! minería! de! datos! explicadas,! y! se! obtienen! los! resultados! de! las!mediciones!de!los!errores!de!los!modelos!de!predicción!creados!por!los!diferentes!algoritmos!empleados.! En! la! Tabla! 3! observamos! que! el! método! de! máquinas! de! soporte! vectorial!presenta!el!menor!MAE,!RMSE!y!RELE.!En!la!Tabla!4!se!presentan!las!variables!de!entrada!

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seleccionadas!junto!con!los!resultados!del!análisis!de!importancia!de!cada!una.!Aquí!podemos!ver! que,! si! bien! gran! parte! de! los! ingresos! hospitalarios! están! afectados! por! el! día! de! la!semana,!algunos!contaminantes!como!el!NO2,!SO2,!PM!y!O3!además!de!ciertas!palabras!clave!en!mensajes!de!Twitter!tienen!también!un!papel!en!la!explicación!de!los!ingresos!hospitalarios.!Es!por! lo! tanto! importante!destacar!que!el!papel!de! las! redes!sociales!como!estimador!de!eventos!parece!cobrar!importancia!en!la!segunda!parte!del!estudio.!!!+ MLR+ SVM+ CART+ RF+ ANN+ GBM+ Bagged+CART+MAE+ 149,6523! 143,0234! 191,2768! 157,0166! 153,9616! 169,4191! 160,3384!RMSE+ 258,8015! 252,6663! 289,6049! 254,7269! 261,0873! 260,9216! 266,5853!RELE+ 0,118853! 0,118213! 0,157425! 0,124847! 0,121496! 0,134301! 0,128059!Tabla&3&Medición&de&los&errores&de&media&móvil&(MAE),&error&cuadrático&medio&(RMSE)&y&error&relative&(RELE)&

!Variable+de+Entrada+ Importancia+ Variable+de+Entrada+ Importancia+Ingresos!hosp!lag! 9,005055692! air! 0,174302893!

NO2! 0,904485429! tos! 0,171903771!PM10! 0,474281243! garganta! 0,161709414!T! 0,45502817! sick! 0,092588606!

PM2.5! 0,332469096! ambiental! 0,079478177!HR! 0,319111788! contaminación! 0,063329867!SO2! 0,28526195! respiración! 0,063147365!O3! 0,267585415! ! !

Tabla&4&Análisis&de&la&importancia&de&las&variables&de&entrada&seleccionadas&para&el&modelo&de&predicción&&

!! Conclusiones+++Aunque!los!resultados!del!CCF!no!permitan!ratificar!más!que!la!hipótesis!(iii)!establecida!en!los!objetivos,!la!correlación!entre!variables!de!contaminación!y!de!comentarios!de!Twitter!con!los!ingresos!hospitalarios!no!pueden!obviarse.!!!Ciertamente!la!autocorrelación!de!los!ingresos!hospitalarios!con!lo!ocurrido!una!semana!antes!indica!una!fuerte!dependencia!de!esta!variable!con!el!día!de! la!semana,!sin!embargo!esta!relación! puede! aún!mejorarse.! Efectivamente,! el! empleo! de! técnicas! de!minería! de! datos!permiten! la! construcción! de! un! modelo! basado! en! el! algoritmo! de! máquinas! de! soporte!vectorial!que!predice!con!dos!días!de!antelación!el!número!de!ingresos!hospitalarios!con!un!88%!de!precisión.!!+La! elaboración! de! este! modelo! permite! mejorar! la! gestión! de! los! recursos! hospitalarios,!adelantándose!por!ejemplo!a!la!formación!de!largas!colas!de!pacientes.!Además,!este!estudio!abre!líneas!de!investigación!futuras.!!!Se!han!identificado!periodos!de!crisis!en!Twitter!en!los!que!los!comentarios!que!contienen!las!!palabras! clave! seleccionadas! tomaban! valores! extremadamente! altos.! Sería! interesante!identificar!el!hecho! real!que!condujo!a!dichas!crisis!y!así!poder!estimar! la! reacción!social.!Además,! este! estudio! podría! completarse! con! un! análisis! de! la! estancia! hospitalaria!agregando! los! datos! por! tipo! de! diagnóstico! o! tiempo! de! estancia! del! paciente,! para! así!aumentar! la! información! disponible! acerca! de! la! salud! pública,! permitiendo! la! toma! de!decisiones!clínicas!basadas!en!una!mayor!información.!!++!!

!

!

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!!

! !

Table&of&Contents&

1! INTRODUCTION*.....................................................................................................................*13!1.1! AIR!POLLUTION:!A!PUBLIC!HEALTH!PROBLEM!ON!THE!RISE!..................................................................!13!

1.1.1! Defining)pollution)and)air)pollutants).............................................................................)13!1.1.2! Sources)of)pollutants).....................................................................................................)13!1.1.3! Pollutant’s)effects)on)human)health)..............................................................................)14!

1.2! ENVIRONMENTAL!LEGISLATION!AND!DEALING!WITH!POLLUTION!CRISIS!................................................!16!1.2.1! Historical)background)....................................................................................................)16!1.2.2! Current)EU)legislation)and)resulting)abatement)measures)for)common)pollutants).....)17!1.2.3! USA)legislation,)resulting)abatement)measures)and)comparison)with)EU)for)common)pollutants)......................................................................................................................................)19!1.2.4! Legislation)and)abatement)measures)for)organic)pollutants)in)the)EU)and)USA)..........)21!

1.3! CONCLUSION!.............................................................................................................................!25!

2! STATE*OF*THE*ART*.................................................................................................................*27!2.1! AIR!QUALITY!RELATED!STUDIES!.....................................................................................................!27!

2.1.1! Studies)using)the)static)approach)..................................................................................)27!2.1.2! Studies)using)the)dynamic)approach).............................................................................)27!2.1.3! Main)shortcomings)of)the)existing)studies)....................................................................)29!

2.2! AIR!QUALITY!AND!ITS!HEALTH!EFFECT!STUDIES!.................................................................................!30!2.2.1! Type)of)study).................................................................................................................)30!2.2.2! Population)groups).........................................................................................................)30!2.2.3! Pollutants)studied)and)source)of)data)...........................................................................)30!2.2.4! Time)of)exposure)...........................................................................................................)31!2.2.5! Geographical)location)and)scale)of)the)studies).............................................................)31!2.2.6! Health)effects)of)interest)...............................................................................................)32!2.2.7! Common)methodology)..................................................................................................)32!2.2.8! Main)shortcomings)of)the)existing)studies)....................................................................)32!

2.3! AIR!QUALITY!AND!SOCIAL!AWARENESS!STUDIES!................................................................................!33!2.3.1! Sources)of)air)pollution)risk)perception).........................................................................)33!2.3.2! Information)about)the)air)pollution)crisis:)role,)sources,)current)contents)and)public)needs.) 36!2.3.3! Moving)from)information)to)action)...............................................................................)37!2.3.4! The)rise)of)environmental)concern)and)social)media)....................................................)38!2.3.5! Main)shortcomings)of)the)existing)studies)....................................................................)38!

2.4! SOCIAL!AWARENESS!OF!HEALTH!IMPACTS!OF!AIR!POLLUTION!STUDIES!..................................................!39!2.4.1! Personal)invulnerability,)cognitive)dissonance)and)neighbourhood)halo)effect)............)39!2.4.2! Limits)in)the)acknowledgement)of)air)pollution)health)impacts)....................................)40!2.4.3! Main)shortcomings)of)the)existing)studies)....................................................................)40!

2.5! AIR!QUALITY,!SOCIAL!AWARENESS!AND!HEALTH!EFFECTS!RELATED!STUDIES!...........................................!41!2.6! HIGHLIGHTS!OF!THE!LITERATURE!...................................................................................................!41!

3! OBJECTIVES*............................................................................................................................*43!

4! METHODOLOGY*.....................................................................................................................*45!4.1! STUDY!AREA!..............................................................................................................................!45!4.2! DATA!COLLECTION!......................................................................................................................!45!

4.2.1! Air)pollution)...................................................................................................................)45!4.2.2! Public)health)data)..........................................................................................................)49!4.2.3! Social)awareness)data)...................................................................................................)50!

!

!

4.2.4! Holiday)Data)..................................................................................................................)54!4.2.5! Data)aggregation)..........................................................................................................)54!

4.3! ANALYTICAL!TECHNIQUES!............................................................................................................!55!4.3.1! Selection)of)techniques)for)bilateral)relationships).........................................................)55!4.3.2! Selection)of)techniques)for)predictive)model).................................................................)55!

5! RESULTS*.................................................................................................................................*59!5.1! DESCRIPTIVE!ANALYSIS!OF!THE!SITUATION!IN!THE!CITY!OF!MADRID!......................................................!59!

5.1.1! Air)quality)assessment)...................................................................................................)59!5.1.2! Hospital)admissions)assessment)...................................................................................)62!5.1.3! Twitter)messages)related)to)pollution)assessment)........................................................)65!

5.2! CCF!RESULTS!.............................................................................................................................!68!5.2.1! Correlation)between)air)pollution)and)public)health).....................................................)68!5.2.2! Correlation)between)Twitter)messages)and)air)pollution)..............................................)71!5.2.3! Correlation)between)Twitter)messages)and)public)health)............................................)72!5.2.4! Conclusions)of)the)CCF)results).......................................................................................)75!

5.3! FORECASTING!MODEL!.................................................................................................................!75!5.3.1! Hospital)admissions)autocorrelation)function)...............................................................)75!5.3.2! Model)training)and)testing)............................................................................................)76!5.3.3! Model)improvement)......................................................................................................)77!

5.4! EVALUATION!OF!IMPACTS!AND!RESPONSIBILITIES!OF!THE!PROJECT!.......................................................!78!5.4.1! Social)impacts)of)the)project).........................................................................................)78!5.4.2! Ethical,)legal)and)professional)responsibilities)..............................................................)79!

6! CONCLUSIONS*.......................................................................................................................*81!6.1! CONCLUSIONS!OF!THE!PROJECT!.....................................................................................................!81!6.2! LIMITATIONS!AND!PROPOSITION!OF!FURTHER!RESEARCH!...................................................................!82!

7! PLANNING*OVER*TIME*OF*THE*PROJECT*.................................................................................*83!7.1! PROJECT!MANAGEMENT!..............................................................................................................!83!7.2! DATA!COLLECTION!......................................................................................................................!83!7.3! EDUCATION!ON!THE!PROBLEM!......................................................................................................!83!7.4! RESOLUTION!OF!THE!PROBLEM!.....................................................................................................!83!7.5! WRITING!OF!THE!RESEARCH!PROJECT!DESCRIPTION!.........................................................................!84!7.6! ELABORATION!OF!THE!ORAL!PRESENTATION!TO!THE!JURY!...................................................................!84!

8! BUDGET*OF*THE*PROJECT*.......................................................................................................*89!8.1! UNIT!PRICE!TABLES!.....................................................................................................................!89!

8.1.1! Unit)price)table)of)workforce).........................................................................................)89!8.1.2! Unit)price)table)of)material)items)..................................................................................)89!8.1.3! Unit)price)table)of)auxiliary)items)..................................................................................)89!

8.2! UNIT!PRICE!OF!WORK!UNITS!.........................................................................................................!90!8.3! UNIT!PRICES!OF!WORK!UNITS’!BREAKDOWN!....................................................................................!90!8.4! BUDGET!...................................................................................................................................!92!

9! REFERENCES*...........................................................................................................................*93!

Estimators!of!social!awareness!concerning!the!pollution!crisis!in!the!city!of!Madrid!!!

Lucía!VegaCPenichet!Andrada! ! 13!

!

1! INTRODUCTION!!

1.1+ Air+pollution:+a+public+health+problem+on+the+rise++!

Epidemiologic!studies!have!evidenced!that!air!pollution!affects!both!mortality!and!morbidity!in!humans.!Estimates!from!the!global!burden!of!disease!(GBD)!make!air!pollution!responsible!for!1,4%! of! mortality! worldwide,! 2%! of! all! cardiopulmonary! diseases! and! 0,5%! of! disabilityCadjusted!life!years!(DALYs)!(Ostro,!2004).!DALYs!aim!to!measure!the!number!of!healthy!years!lost!in!a!population!due!to!premature!mortality!and!morbidity!(Hänninen!et!al.,!2014).!A!more!recent!study!than!the!one!carried!out!by!the!GBD!makes!air!pollution!accountable!for!6%!of!all!mortality!in!Europe!(Künzli!et!al.,!2000).!Also!in!Europe,!it!is!estimated!that!poor!air!quality’s!effects!on!health!are!worse!than!those!of!road!traffic!accidents,!making!air!pollution!the!biggest!environmental! problem! causing! premature! death! (European! Commission,! 2013).! If! the!morbidity!consequences!of!air!pollution!are!also!taken!into!account,!it!seems!inevitable!to!admit!that!air!pollution!is!a!public!health!problem!that!must!be!addressed!promptly.!!To!be!able!to!confront!this!though,!it!seems!necessary!to!determine!what!is!considered!to!be!air!pollution,!the!!sources!of!!pollutants!and!the!specific!effects!air!pollutants!have!on!human!health.!

!1.1.1! Defining!pollution!and!air!pollutants!!

!Air!pollutants!are!defined!as!substances!potentially!harmful!to!humans,!animals,!vegetation!or!materials.!Their!effects!depend!on!time!of!exposure,!concentration,!chemical!composition!and!many!other!factors,!but!even!so!the!pollutants!can!be!classified!into!four!main!groups:!gaseous!pollutants,! particulate! matter,! persistent! organic! pollutants! and! heavy! metals! (Kampa! &!Castanas,! 2008).! The!United! States! Environmental! Protection! Agency! (EPA)! controls! 187!hazardous!air!pollutants’!emissions!but!defines!only!six!as!common!air!pollutants:!groundClevel!ozone!(O3),!carbon!monoxide!(CO),!sulphur!dioxide!(SO2),!particular!matter!(PM!consisting!of!PM2,5!and!PM10),!lead!(Pb)!and!nitrogen!oxides!(NO!and!NO2).!These!common!air!pollutants!fit!into!the!aforementioned!categories!of!gaseous!pollutants!and!particulate!matter.!!!Even!if!they!are!not!included!in!the!six!common!pollutants,!some!organic!pollutants!such!as!toluene,! benzene,! ethylbenzene,! xylene! isomers,! hexane! and! methane! should! not! be!neglected!due!to!their!presence!in!daily!life!through!consumer!products!and!combustible!fuels!amongst! others.! These!organic! pollutants! are! degraded! in! a! few!days! in! the! air! thanks! to!sunlight! or! other! chemicals.!However,! the! decomposition! is! harder! indoors,!where! organic!pollutants!are!the!most!harmful.!!

!1.1.2! Sources!of!pollutants!!

!The!nature!of!pollutants!in!the!air!has!changed!in!the!last!50!years.!SO2!was!the!most!popular!air!pollutant!for!a!long!time,!its!source!being!the!combustion!of!fossil!fuels!containing!sulphur,!such!as!coal!and!heavy!oils.!Today!its!levels!have!decreased!but!as!new!sources!of!energy!appear,!new!pollutants!have!taken!the!relay.!Effectively,!NO2!is!generated!by!the!combustion!of!different!fossil!fuels!in!stationary!sources!such!as!heating!or!power!generation!stations!and!mobile! sources! such! as! motor! vehicles.! Incomplete! combustion! in! motor! vehicles! also!generates!CO.!!!Vehicle!exhaust! is!also,!along!with! some!consumer!product! industries,! the!main! source!of!organic!pollutants.!Toluene,!benzene,!ethylbenzene,!xylene!isomers,!hexane!and!methane!are!found!in!crude!oil!and!hence!are!discharged!into!the!air!when!fuels!are!burnt.!However,!industry!processes!involving!these!organic!pollutants!are!also!a!big!contributor!to!their!presence!in!the!

Introduction!!

Escuela!Técnica!Superior!de!Ingenieros!Industriales!(UPM)!14!

environment!(air,!water!and!soil).!The!paint!and!varnish!industries!use!toluene,!ethylbenzene!and!xylenef!benzene,!ethylbenzene,!xylene!and!hexane!are!used!to!make!cleaning!agents,!solvents! and! drugsf! glues! and! adhesives! contain! toluene! and! hexanef! the! synthetic! fibre!industry!consumes!toluene!and!benzene…!All!of!these!industries!create!consumer!products!that,! when! used,! discharge! these! volatile! components! into! the! environment.! Furthermore,!benzene!is!a!byCproduct!of!cigarette!smoke,!methane!is!the!main!component!of!natural!gas!and!xylene!is!necessary!in!the!printing,!rubber!and!leather!industries.!!!O3!in!lower!ground!levels!is!a!product!of!a!series!of!complex!chemical!reactions!involving!NO2,!sunlight! and! hydrocarbons.! Finally,! particulate! matter! comes! from! very! varied! sources!including!factories,!power!plants,!refuse!incinerators,!motor!vehicles,!construction!activity,!fires!and!natural!windblown!dust.!They!are!mixtures!of! liquid!and!solid!components!and!can!be!classified!according!to!their!size.!PM10!or!thoracic!particles!are!those!with!a!diameter!inferior!to!10!µm.!They!can! reach! the!upper! respiratory! track.!PM2,5!or! respirable!particles!have!a!diameter!inferior!to!2,5!µm!and!can!reach!the!alveoli.!PM2,5!can!be!directly!emitted!or!can!be!formed!resulting!to!NOX,!SOX!and!volatile!organic!compounds!(VOCs)!emissions.!!!All!of!these!pollutants!reach!the!human!organism!mainly!by!inhalation!and!ingestion!resulting!of!the!contamination!of!food!and!water.!Dermal!contact!is!a!much!less!popular!way!to!attack!the!human!body!for!nonorganic!pollutants,!which,!once!inside!the!human!organism,!either!act!as!proCoxidants!in!lipids!and!proteins!or!as!free!radical!generators,!triggering!a!series!of!cell!processes!that!can!even!involve!DNA!nucleotides!(Kampa!&!Castanas,!2008f!Williams,!1999).!Adding!to!inhalation!and!ingestion,!dermal!contact!is!also!an!effective!path!to!human!health!for!organic!pollutants.!!

!1.1.3! Pollutant’s!effects!on!human!health!!

!Indeed,!pollutants!can!be!the!source!of!skin!irritation!and!difficulties!in!breathing,!but!can!also!be! involved! in!more! serious! diagnosis! such! as! lung! cancer.!Many! studies! have! found! the!correlation!between! individual!air!pollutants!and!specific!diseases.!The!effects!on!health!of!each!of!the!common!pollutants!are!assembled!in!Table!1.!!

Nevertheless,! air! pollution! does! not! affect! all! population! groups! in! an! equivalent! manner.!Elderly! people! seem! to!be! the!most! exposed.!According! to! the!World!Health!Organisation!(WHO)!81%!of!the!deaths!attributed!to!air!pollution!were!for!people!aged!over!60!(Ostro,!2004).!Likewise,! the!age!group!over!65!was!considered! to!be!2! to!5! times!more!vulnerable! to!air!pollution!than!any!other!age!group!(Kan!et!al.,!2008).!The!population!at!risk!must!also!include!children!under!5!years!old!and!in!foetal!state.!Once!again!the!WHO!relates!3%!of!total!deaths!attributable!to!outdoor!air!pollution!to!children!under!5!(Ostro,!2004).!When!organic!pollutants!are! involved,! it! is! the! workers! of! the! industries! enumerated! above! that! are! the! most!endangered.!Effectively,!though!effects!on!health!of!the!organic!pollutants!discussed!in!Table!1!tend!to!disappear!after!the!pollutant!has!left!the!body,!longCterm!exposure!can!make!effects!longerClasting!and!even!cause!product!build!up,!resulting!in!more!serious!health!effects!such!as!cancer!or!even!death.!!

!

Pollutant+ Health+Effects++O3+ cough!days!and!lower!respiratory!symptoms!(LRS)!in!children!(Künzli!et!al.,!

2000),!lung!inflammation!(Kampa!&!Castanas,!2008).!!associated!to!smog!and!asthma!attacks!(Melorose,!Perroy,!&!Careas,!n.d.)!



CO+ mortality!for!all!ages,!cardiovascular!and!respiratory!disease!mortality!(Proyecto!et!al.,!1999),!modification!of! !haemoglobin!conformation,! reducing! its!capacity! to! transfer!oxygen,! provoking! impaired! concentration,! slow! reflexes! and! confusion!(Kampa!&!Castanas,!2008).!

NO2+ cardiovascular!mortality!(Proyecto!et!al.,!1999),!nose!and!throat!irritation,!bronchoconstriction,! dyspnoea! and! emphysemaClike! lesions! (all! respiratory!related)!(Kampa!&!Castanas,!2008).!!

SO2+ nose!and!throat!irritation,!bronchoconstriction!and!dyspnoea!(Kampa!&!Castanas,!2008)!

PM+ urgent! care! visits,! asthma! attacks,! acute! bronchitis,! respiratory! symptoms,!and!restrictions!in!activity,!!neo!natal!or!infant!mortality!associated!to!acute!respiratory!infections,!low!birth!weight! and! higher! rates! of! prematurity! (Künzli! et! al.,! 2000f! Ostro,! 2004f!Proyecto!et!al.,!1999).!

PM10+ mortality!for!all!ages,!infant!and!childhood!mortality!for!respiratory!disease!(Ostro,!2004).!

PM2,5+ cardiovascular!mortality!(Ostro,!2004),!!cancer!lung!(Künzli!et!al.,!2000f!Ostro,!2004),!!mortality! and! morbidity! concerning! cardiopulmonary! disease! and! chronic!bronchitis!(Künzli!et!al.,!2000),!lung!inflammation!(Kampa!&!Castanas,!2008)!

Toluene+ Attacks! the! nervous! system,! provoking! tiredness,! confusion,! weakness,!drunkenCtype!actions,!memory!loss,!nausea!and!loss!of!appetite.!!LongCterm!exposure!can!lead!to!hearing!and!colourCvision! loss!and!even!to!brain!damage.!!Extreme!exposure1!creates!loss!of!memory,!muscle!control!and!balance!and!decreases! mental! abilities.! If! pregnant! women! are! exposed! in! extreme!conditions!birth!defects!in!children!such!as!retardation!of!mental!abilities!and!growth!are!likely.!!(Agency!for!Toxic!Substances!&!Disease!Registery,!n.d.Ca)!

Benzene+ Inhalation!of!very!high!levels!of!benzene!can!cause!deathf!of!high!levels!might!trigger! drowsiness,! dizziness,! rapid! heart! rate,! headaches,! confusion! and!unconsciousness.!!Ingestion! of! high! levels! of! benzene! can! cause! vomiting,! irritation! of! the!stomach,!sleepiness,!convulsions,!rapid!heart!rate!and!death.!!Most!harmful!effects!are!bloodCrelated.!It!decreases!number!of!red!blood!cells,!provoking! anaemia! and! irregularity! in! menstrual! periods! and! decrease! in!ovaries’!size!for!women.!Long!term!exposure!might!cause!leukaemia.!!(Agency!for!Toxic!Substances!&!Disease!Registery,!2007)!

Ethylbenzene+ Short! term! exposure! leads! to! irritation! of! throat! and! eyes,! dizziness! and!vertigo.!!Carcinogen!if!exposure!is!long!term.!(Agency!for!Toxic!Substances!&!Disease!Registery,!2015)!

Xylene+ Daily!exposure!is!considered!to!be!very!low!and!no!health!effects!are!related.!!High! levels! of! exposure! induce! irritation! of! skin,! eyes,! nose! and! throat,!difficulty! in! breathing,! headaches,! confusion,! memory! loss,! reduction! of!reaction!time!and!muscle!coordination!and!even!changes!in!liver!and!kidneys.!!Very!high!levels!are!deadly.!!(Agency!for!Toxic!Substances!&!Disease!Registery,!n.d.Cb)!

Introduction!!


Hexane+ Inhalation! provokes! dizziness,! nausea,! weakness,! unconsciousness.! Can!cause!coma!state.!!If!swallowed,!can!cause!chemical!pneumonitis.!!Long! term! or! repeated! exposure! is! responsible! for! nervous! system!effects!such!as!polyneuropathy.!!Can!affect!human!reproduction.!!

Methane+ Inhalation!causes!suffocation!since!methane!lowers!the!oxygen!content!of!air,!resulting!in!unconsciousness!or!death.!!Ingestion!or!skin/eye!contact!leads!to!frostbite:!skin!is!frozen,!becoming!hard,!pale!and!numb.!!

Table&1&Health&effects&associated&to&five&of&the&common&pollutants&defined&by&the&EPA&

1Extreme!exposure!usually!refers!to!inhalation!as!drug!substitute.!!!Air!pollution!seems!therefore! to!be!an! important!subject!of!concern! for!public!health:! it! is!a!cause!of!mortality,!it!enhances!certain!preCexisting!diseases!and!provokes!new!ones,!not!only!in!the!respiratory!system!but!also!on!other!areas!like!the!cardiovascular,!cardiopulmonary!and!even!nervous!systems.!The!goal!of!public!health!institutions!is!to!reduce!pollution!health!effects!and!this!requires!a!reduction!of!air!pollution!itself.!Indeed,!a!growing!effort!for!controlling!air!pollution!is!manifested!in!the!evolution!of!environmental!law.!!

+1.2+ Environmental+Legislation+and+dealing+with+pollution+crisis+

!1.2.1! Historical!background!!

!Air!pollution!concerns!have!a!long!history!in!society,!nevertheless,!it!is!only!put!into!words!in!the!20th!century!when!the!first!air!pollution! legislations!are!approved!worldwide.!This!primal!awareness!of!air!pollution,!and!the!effort!to!reduce!it!it!manifests,!are!partly!a!consequence!of!an!air! pollution!disaster! that! took!place! in!London! in!1952:!The!Great!Smog.!The!poor!air!quality! in! the! city! resulting! of! coal! combustion! combined! with! cold! weather! and! windless!conditions!caused!a!pollution!event!so!great!it!was!made!responsible!of!over!4!000!deaths!at!the! time! C! that! are! estimated! today! at! 12! 000C! and! of! over! 100! 000! illnesses! related! to!respiratory!issues.!!

!This! dreadful! event! triggered,! as!we! have!mentioned,! the! first! legislation! efforts! aiming! to!reduce!air!pollution.!In!1954!the!United!Kingdom!(UK)!engaged!in!the!City!of!London!Act!and!on!the!Clean!Air!Act!two!years!later.!This!first!attempt!to!reduce!air!pollution!concentrated!on!creating!smoke!control!zones!and!encouraging!households! to!shift! from!coal! to!smokeless!fuels.!This!event!crossed!borders!and!in!1955!the!United!States!of!America!(USA)!approved!the!Air!Pollution!Control!Act,!that!would!lead!the!way!for!the!posterior!Clean!Air!Acts!to!come!(in! 1963,! 1970! and! 1990).! Though! these! first! measures! were! not! highly! effective! in! their!objective!of!actually!reducing!pollution,!they!did!plant!a!seed!of!worry!and!concern!about!air!pollution!and!so!air!pollution!was!born!as!a!social!concern.!!However,! it! is! not! until! December! 1972! that! the! first! air! pollution! related! legislation! was!approved! in!Spain,!promoted!by! the!Conference!on! the!Human!Environment!of! the!United!Nations!(UN)!held! in!Stockholm!in!June!of! that!same!year.!The!Conference!established!26!principles!on!environment!and!development!and!presented!a!plan!of!action!consisting!of!109!recommendations.! Indeed,! the!Spanish!Law!38/1972!of! the!22!of!December!deals!with! the!protection!of!the!tropospheric!environment!and!it!leads!to!declaring!the!city!of!Madrid!as!an!area!of!polluted!atmosphere!in!1977.!The!reaction!to!this!new!state!was!quite!immediate:!in!1978!Madrid!disposed!of!16!air!quality!monitoring!stations.!Today!there!are!24!stations!that!take!measures!of!up!to!16!different!pollutants!including!gaseous!pollutants,!particulate!matter!and!persistent!organic!pollutants.!



!The!growth!of!the!web!of!monitoring!stations!in!Madrid!is!only!a!reflection!of!the!evolution!of!the! environmental! law! in! Spain.! Though! the! country! made! some! efforts! on! its! own,! their!integration!in!the!European!Union!(EU)!in!1986!widened!significantly!the!scope!of!legislation!in! this! field.! Entering! into! the! EU! meant! the! application! of! an! ius& commune.! Indeed,! the!common! law! in! the! environmental! field! was! first! developed! in! the! 1970s,! after! the! UN’s!Conference!in!Stockholm,!and!focused!on!reducing!the!emission!of!pollutants!to!improve!the!quality!of!air!or!water!as!individual!goals.!The!Single!European!Act!of!1987!includes!for!the!first!time!an!Environment!Titlef!in!1993!the!Treaty!of!Maastricht!defines!the!environment!as!an!official!policy!areaf!in!1999!the!Treaty!of!Amsterdam!aims!to!integrate!environmental!protection!into! all! sectorial! policies! and! finally,! in! Lisbon! in! 2009! climate! change! and! sustainable!development!in!relations!with!third!world!countries!became!specific!goals!of!the!EU.!!!

1.2.2! Current! EU! legislation! and! resulting! abatement! measures! for! common!pollutants!!

!When! looking! at! the! EU! legislation! using! the! keywords! “air! pollution”! on! title! or! text,! 993!documents!are!found!including!directives,!regulations!and!decisions,!dating!from!1969!to!2016.!This!shows!a! real!effort! in! the!EU! legislation! to!adapt! itself! to! the!ever!changing!nature!of!pollution.!Today!the!UE!emphasizes!on! links!between!environmental! issues!and!addresses!their! global! dimension,! moving! from! remediation! to! prevention! of! pollution! (European!Commission,!2014).!In!fact,!considering!the!global!dimension!of!the!air!quality!problem,!the!latest!Directive!approved!C!and!currently!valid!C!by!the!Commission!in!2008!aimed!to!unify!the!First,! Second! and! Third! Daughter! Directives! of! 1999,! 2000! and! 2002:! The! Directive!2008/50/EC! deals! with! the! assessment! and! management! of! air! quality,! establishing! limit!values! and! monitoring! requirements! for! each! pollutant! that! was! treated! separately! in! the!Daughter!Directives.!!

!The!Directive!insists!on!the!importance!of!monitoring!pollutants!and!making!the!data!generated!available!in!order!to!have!a!better!understanding!of!air!pollution.!It!establishes!requirements!for!location!and!minimum!number!of!sampling!points!necessary,!differentiating!the!six!common!pollutants! in! two!groups:!O3! is!dealt!with!separately!and!the!rest!of!pollutants!configure!the!second!group.!The!“special!treatment”!given!to!O3!is!due!to!the!fact!that!O3!is!formed!in!the!atmosphere!and!not!emitted:!it!is!the!product!of!a!reaction!of!emitted!precursors!such!as!NOX,!VOCs,!CO!and!methane!(Downey!et!al.,!2015).!The!admitted!measurement!methods!are!also!specified.!The!information!collected!has!to!be!provided!to!the!Commission!and!therefore!has!to!be!standardized!in!format.!!

!The! measures! obtained! from! these! sampling! points,! once! analysed,! determine! the!management!strategy!to!be!followed.!When!air!pollution!is!below!limit!values,!Member!States!are!encouraged!to!improve!or!at!least!maintain!the!current!concentration!of!pollutants.!If!the!limit! values! are! exceeded,! the! Member! States! have! to! create! an! air! quality! plan! (AQP)!containing!basic!information!of:!location!of!excess!of!pollution,!responsible!authorities,!nature!and!assessment!of!pollution,!origin!of!pollution,!analysis!of!the!situation!and!measures!adopted!before!or!after! the!current!Directive! in!order! to! improve! the!pollutants’!concentration! in! that!area.!Furthermore,!looking!to!prevent!pollution!as!well!as!reducing!it,!when!there!exists!a!risk!of!exceeding!one!or!more!limit!values,!short!term!action!plans!must!also!be!developed.!The!Directive! must! be! transposed! to! national! law! and! when! the! latter! is! infringed,! effective,!proportionate!and!dissuasive!penalties!must!be!proposed.!

!This!Directive!focuses!on!PM2,5!values!since!until!now,!no!threshold!value!below!which!PM2,5!does!not! affect! human!health! has!been! found.! It! redefines! this! pollutant’s! limit! values!and!requires!its!measurement!also!in!rural!background!areas!far!from!any!source!of!pollution.!!

!

Introduction!!


A!proposal!for!a!new!Directive!was!published!in!2013,!inside!of!a!New!Policy!Package!to!“clean!up!Europe’s!air”!(European!Commission,!2013)!that!also!contained!new!air!quality!objectives!up!to!2030!and!new!national!and!stricter!emission!ceilings!for!the!six!main!pollutants.!As!stated!by! the! Commission,! the! Package! only! updates! existing! legislation! and! considers! that! its!application!would!create!health!benefits!estimated!at!€40!billion!a!year.!It!pretends!to!avoid!58.000! premature! deaths! by! 2030! and! save! a! total! of! 198.000! km2! of! land! from! nitrogen!pollution!and!acidification.!!

!The!EU!therefore!defines!the!limit!values!and!the!infrastructure!necessary!(sampling!points!and!measurement!methods)!in!order!to!assess!and!manage!air!quality,!giving!the!freedom!and!responsibility! to! each! Member! State! to! elaborate! action! plans! to! deal! with! air! pollution!exceedances.!The!EU!must!approve!the!plans!but!only!controls!its!results!once!the!period!they!establish!to!reduce!the!concentration!of!pollutants!is!over.!!!(Miranda!et!al.,!2015)! reviews!AQPs! from!different!urban! regions,!normally!capitals,! ! in!16!Member!States!that!are:!UK,!France,!Germany,!Sweden,!Belgium,!Denmark,!Greece,!Ireland,!Latvia,!Malta,!Netherlands,!Poland,!Portugal,!Spain,!Portugal!and!Romania.!!The!latest!European!report!on!air!quality!insists!on!the!impact!of!high!levels!of!PM!and!O3!and!so!the!abatement!measures!of!pollutant!emissions!proposed!in!the!AQPs!are!directed!to!the!traffic!sector!due!to!its!link!to!PM!and!NO2!emissions!(NO2!is!an!O3!precursor).!The!measures!gathered!from!the!different!AQPs!can!be!classified!into!8!groups.!Their!inclusion!in!legislation,!spatial!application!scale!and!time!horizon!of!visible!effects!are!reviewed!in!Table!2.!!!Measure++ Regulatory+

implications++Spatial+ Application+Scale+

Time+ horizon+ of+measures+

Technical+measures+ none! regional!and!national!! C!Traffic+management++ partly!! local! long!term!Encouraged+ use+ of+public+transport+

none! local!and!regional! short!term!!

Traffic+restriction+ total! local! long!term!!Road+construction+ none! cover! different!

spatial! domains!depending! on!extension! and!construction!type.!!

long!term!

Speed+reduction+ total! regional! short!term!!Street+cleaning++ partly!! local! short!term!!Others++ partly!! !C! mediumClong!term!!Table&2&Review&of&abatement&measures&in&European&AQPs&

To!explain!the!difference!in!regulatory!implications!of!the!different!measures,!their!nature!has!to!be! taken! into!account.!Abatement!measures!can!be! technical!measures!(TMs)!and!nonCtechnical!measures!(NTMs).!!TMs!are!most!of!the!time!“end!of!pipe”!technologies:!they!aim!to!reduce!emissions!right!before!their!release!into!the!atmosphere,!without!attacking!the!sources!of!emission.!On!the!other!hand,!NTMs!aim!to!eliminate!the!driving!forces!of!pollution!either!by!changing! people’s! behaviour! or! by! changing! the! structure! of! the! activity,! for! example! by!introducing!technologies!that!reduce!energy!demand.!!Investment!on!introduction!of!electric!and!hybrid!vehicles!(classified!in!Table!2!as!TMs),!use!of!public!transport!and!even!shared!transport!measures!such!as!the!European!initiative!car2go!or! more! particularly! the! bike! sharing! service! BiciMad! in! Madrid,! public! transport! network!enlargement!and!improvement!of!traffic!flow!(in!Table!2!as!road!construction)!are!considered!as!behaviourCbased!measures!and!so!they!cannot!be!regulated.!Nevertheless,!measures!such!as!traffic!and!speed!restriction!are!easy!to!regulate!and!impose!on!citizens.!!!!



However,! since! the!environment!and!specifically! air! quality! transcends!any!mankind!made!barrier,! the! effort! made! by! the! EU! to! achieve! a! cleaner! air! is! based! on! Member! State’s!cooperation! and,! in! order! to! be! effective,! should! be! backed! up! by! the! rest! of! the!World.!Effectively,! it! is! interesting! to! study! the! legislation! somewhere! else! in! the!world! to! identify!different! strategies! for! dealing! with! air! pollution.! For! this! purpose,! USA! legislation! will! be!analysed.!!!!

1.2.3! USA! legislation,! resulting! abatement!measures! and! comparison!with!EU! for!common!pollutants!

!The!legislation!that!regulates!air!pollution!in!the!USA!is!the!Clean!Air!Act!(CAA),!that!was!first!approved!in!1955!as!it!has!been!mentioned!before,!and!has!known!many!versions!until!the!most!recent!one!from!1990.!The!CAA!requires!the!EPA!to!set!National!Ambient!Air!Quality!Standards!(NAAQS)!for!the!six!common!pollutants.!Consequently,!each!State!has!to!generate!a!State! Implementation!Plan! (SIP)! to!attain!and!maintain! the!NAAQS!set.!These!SIPs!are!developed!by!state!or!local!air!management!agencies!and!need!the!approval!of!the!EPA!three!years!after!the!creation!of!an!NAAQS!or!modification!of!an!existing!one.!SIPs!are!required!for!nonCattainment!of!NAAQS!areas!but!also!for!attainment!areas,!to!maintain!or!better!their!air!quality.!The!management!structure!on!air!pollution!in!the!USA!seems!therefore!quite!similar!to!the!one!held!by!the!EU:!limit!values!are!determined!and!plans!to!meet!them!must!be!developed!individually!in!States,!and!later!evaluated.!!!First,!it!seems!adequate!to!compare!the!strictness!of!limit!values!and!NAAQS.!Table!3!shows!a!comparison!of!air!quality!limit!values!in!EU!and!USA,!where!EU!limits!appear!definitely!more!restrictive!than!USA’s!in!most!cases.!!!Pollutant+ EU+limit+values++ US+NAAQS+

•! 8!hour!mean!measurements!!O3! 120!! 160!!CO! 10!000! 10!000!!

•! Annual!average!measurements!SO2! 20! 79!PM10! 40! 50!PM2,5! 25! !NO2! 40!! 100!!Benzene! 5! not&set&&

Table&3&Limit&values&in&one&hour&and&NAAQS&for&the&main&pollutants&in&the&EU&and&the&USA&respectively.&All& in&

µg/m3.&

!To!go!further,!it!is!also!interesting!to!evaluate!if!the!measures!taken!in!the!USA!are!similar!to!the!EU’s.!According!to!the!EPA’s!Green!Book!Nonattainment!Areas,!the!State!of!California!is!divided!in!areas!that!are!not!meeting!requirements!for!either!five,!four,!two!or!one!of!the!six!common!pollutants.!The!nonattainment!is!also!significant!in!the!South!of!Arizona!with!areas!that!do!not!meet!requirements!for!either!six,!three,!two!or!one!of!the!six!common!pollutants.!The! rest! of! nonattainment! areas! are! dispersed! and! usually! only! exceed! one! NAAQS.!Therefore,!to!evaluate!the!measures!taken,!the!2016!State!Strategy!for!the!SIP!dealing!with!the! South! Coast! and! San! Joaquin! Valley! areas! in! California! will! be! considered! as!representative!of!the!US.!!!Like!the!latest!EU!reports,!problematic!pollutants!in!California!are!O3,!its!precursor!NOX!and!PM2,5! and! therefore! proposed! actions! in! the! SIP! are! also! focused! on! the! traffic! sector.! If!measures!were!to!be!classified!as!they!were!by!(Miranda!et!al.,!2015),!categories!like!public!

Introduction!!


transport,!speed!reduction,!traffic!restriction!and!street!cleaning!wouldn’t!exist!in!the!California!SIP.!However,!technical!measures!and!in!a!lesser!way!road!construction!would!gather!almost!all!the!proposed!actions.!There!is!an!evident!focus!on!technology!development,!encouraged!by!a!lot!of!incentive!programs!and!funding.!Also,!measures!are!almost!always!backed!up!by!regulation,!which!was!not! the! case! for!most! of!EU!actions.! The!most! significant! proposed!actions!in!the!2016!State!Strategy!for!the!SIP!are!reviewed!in!Table!4.!!!From!this!analysis!it!can!be!concluded!that!EU!and!USA!deal!with!air!quality!in!quite!different!ways:!while!behaviourCbased!actions!are!strong!in!EU’s!strategy,!USA!focuses!on!developing!and! introducing!new! technology.! Indeed,!dealing!with!air!pollution! is!done! through!different!strategies!and!while!some!measures!are!purely!technological,!others!are!very!closely!linked!to!individual’s!collaboration:!whereas!air!pollution!reduction!is!a!legal!responsibility!for!each!State,!it!can!only!be!achieved!with!cooperation!of!its!people.!It!is!therefore!relevant!to!know!the!social!awareness!of!the!air!pollution!problem,!the!level!of!information!public!opinion!has,!since!many!measures!rely!on!individual!behaviour!changes,!as!a!measure!of!the!efficiency!of!the!campaigns!proposed.!!!!Mobile+ Source+Category++

Proposed+Actions++

OnCRoad! LightCDuty!Vehicles!

•! Ensure! that! nonCcombustion! Zero! Emission! Vehicles!(ZEV)!and!PlugCin!Hybrid!Electric!Vehicles!(PHEV)!sales!increase! by! setting! new! emission! standards! in! current!regulation.!!

•! Lower! InCUse! Emission! Performance! Assessment! by!making! assessment! programs! such! as! Smog! Check!Programs!more!effective!!

•! Further!Deployment! of!Cleaner!Technologies! consisting!of! accelerating! penetration! of! ZEVs! and! autonomous!vehicles!by:!!

C! Incentives!and!innovative!funding!programs!to!accelerate!replacement!of!old!vehicles!(rate!should!be!at!70!000!to!85! 000! replacements! per! year! over! a! 7Cyear! period! in!South!Coast)!

C! Support! infrastructure! investment! programs! expanding!charging!and!hydrogen!networks!for!electric!vehicles.!

OnCRoad! Heavy! Duty!Vehicles!!

•! Lower! InCUse! Emission! Performance! Level! by! new!regulations!that!intensify!periodic!Smoke!and!Heavy!Duty!Vehicle!Inspection!Programs!

•! Lower!NOX!Engine!Standards!so!that!combustion!engine!technology!becomes!cleaner!and!ZEVs!are!introduced!as!soon!as!possible!!

•! Advanced!Clean! Transit! aims! to! combine! incentives! so!that! advanced! technology! vehicles! are! purchased! in!transit!fleets!replacement.!!

•! Make! Innovative! Technology! Certification! more! flexible!since! it! might! be! holding! back! manufactures! from!developing!new!technologies.!!

•! Incentive!funding!to!achieve!emission!reduction!from!onCroad!sources!estimated!at!$28!million!



OffCRoad! Federal! and!International!Sources!(locomotives! and!vessels)!!

•! Reduce!locomotive!emission!Standards!!•! Reduce!vessels!emission!Standards!in!collaboration!with!

EPA,!US!Coast!Guard!and!international!partners!!•! Expansion! and! Enhancement! of! existing! funding!

programs!!OffCRoad!Equipment!! •! Incentivise! implantation! of! ZEV! in! lawn! and! garden!

equipment!!•! ZEV!airport!charging!trucks!and!lifts!!

Table&4&Collection&of&&Proposed&Actions&by&Mobile&Source&Category&in&the&2016&State&Strategy&SIP&of&California&&

!!

1.2.4! Legislation!and!abatement!measures!for!organic!pollutants!in!the!EU!and!USA!!!!At!this!point,!it!seems!necessary!to!mention!that!the!air!pollution!regulations!mentioned!until!now!only!include!the!six!common!pollutants!in!USA,!while!the!EU’s!also!considers!benzene.!The!rest!of!the!pollutants!that!this!paper!refers!to!–!toluene,!ethylbenzene,!xylene,!methane,!hexane!and!also!benzene!for!the!USA!–!are!restricted!by!different!legislations!since!they!are!pollutants!of!organic!nature.!!!In!the!EU,!VOCs!are!defined!as!“all!organic!compounds!arising!from!human!activities!other!than!methane,!which!are!capable!of!producing!photochemical!oxidants!by!reaction!with!NOX!in!the!presence!of!sunlight”.!VOCs!therefore!include!toluene,!benzene,!ethylbenzene,!xylene!and! hexane! and! all! legislations! restricting! their! emission! in! the! EU! have! the! reduction! of!groundClevel!O3!as!common!ground.!Indeed,!three!Directives!are!currently!in!force!concerning!VOCs:!!

C! Directive!1999/13/EC!on!the!limitation!of!VOCs!due!to!use!of!organic!solvents!in!certain!activities!and! installations,!which!defines!emission! limit!values!of!VOCs! for!different!activities! including! cleaning,! coating! use! and! manufacturing.! It! establishes! the!obligation!for!MS!to!develop!plans!to!obtain!an!annual!reduction!of!emissions!of!VOCs.!The!limit!values!are!established!for!waste!gases!(final!discharge!of!gases!containing!VOCs! or! other! pollutants! from! an! equipment! into! the! air)! and! fugitive! emissions!(gaseous! discharge! not! in! waste! gases,! uncaptured! emissions! that! reach! the! air!through!windows,!doors,!etc.)!for!different!activities.!!

C! Directive!2001/81/EC!on!national!emissions!for!certain!atmospheric!pollutants,!which!addresses!SO2,!NOX!and!VOCs,!setting!maximum!emission!of!VOCs!on!kilotons!per!MS.!

C! Directive!2004/42/EC!on!the!limitation!of!emissions!of!volatile!organic!compounds!due!to!the!use!of!organic!solvents!in!certain!paints!and!varnishes!and!vehicle!refinishing!products!and!amending!activities!overlapping!with!Directive!1999/13/EC.!This!Directive!aims!to!complement!Directive!2001/81/EC,!which!sets!emission!limit!values!of!VOCs!but!does!not!mention!specific!sources!of!pollutants.!It!sets!a!maximum!VOC!content!for!paints!and!varnishes!and!vehicle!refinishing!products!in!g/L.!!

Legislation!addresses!VOCs!as!a!whole,!not!establishing!emission!limits!for!specific!pollutants.!!!

Meanwhile,!methane!is!a!powerful!greenhouse!effect!gas!and!an!O3!precursor.!However,!until!quite!recently,!there!was!no!regulation!limiting!methane!emissions!in!the!EUf!it!was!explicitly!excluded! in! the! definition! of!VOC! in!Directive! 1999/13/EC.!Methane! is! indirectly! assessed!through! directives! concerning! waste! and! agriculture.! The! Landfill! Directive! 1999/31/EC!mentions!the!necessity!of!reducing!production!of!methane!gas!from!landfills.!The!Climate!and!Energy!Package!aims!to!reduce!greenhouse!gas!(GHG)!emissions!to!20%!below!their!1990!levels,! following! the! lines! established! by! the! Kyoto! Protocol! in! 1997.! GHG! include! CO2,!methane,! N2O,! hydrofluorocarbons,! perfluorocarbons! (PFCs)! and! sulphur! hexafluoride.!Though!the!importance!of!reducing!methane!is!acknowledged!by!legislation,!up!to!date!there!is!no!explicit!limit!value!of!methane!in!the!air.!It!is!indirectly!considered!under!GHG!legislation!

Introduction!!


and!even!in!the!definition!of!VOCs!in!the!Industrial!Emission’s!Directive!2010/75/EU,!but!never!as! an! individual! pollutant.! The!European!Environmental! Bureau! (EEB)! considers!methane!should!be! legislated! in! the!National!Emissions!Ceilings!Directive,!along!with!SO2,!NOX,!CO!and!PM,!however!the!proposal!for!the!new!Directive!mentioned!earlier!still!excludes!methane!emissions!(AirClim,!EEB,!&!ClientEarth,!2013).!!!In! the!USA,!methane! is!not!considered!a!hazardous!pollutant! to!be!controlled!by! the!EPA,!however!toluene,!benzene,!ethylbenzene,!xylene!and!hexane!are!included!in!the!187!list!of!hazardous!pollutants! that! the!Agency!must!monitor.!For!each!one!of! them,! the!Agency! for!Toxic!Substances!and!Disease!Registry!(ATSDR)!offers!a!toxicological!profile!that!includes!a!“Regulations! and! Advisories”! chapter! where! international! and! national! regulations! and!guidelines!for!the!pollutant!in!air,!water!and!soil!are!assembled.!Many!entities!like!the!National!Institute! for! Occupational! Safety! and! Health! (NIOSH)! and! the! Association! Advancing!Occupational! and! Environmental! Health! (ACGIH)! generate! exposure! recommendations! to!these! pollutants,! but! only! the! levels! established! by! the! Occupational! Safety! and! Health!Administration!(OSHA)!are!regulations.!It!is!important!to!notice!that!any!limit!value!regarding!these!pollutants!is!linked!to!the!workers!exposed,!since!it!is!where!concentration!of!pollutants!reach!levels!that!might!pose!a!risk!for!human!health.!Concentration!of!these!pollutants!in!the!air!is!not!otherwise!addressed.!Table!5!gathers!the!OSHA!permissible!exposure!limit!(PEL),!NIOSH’s!Immediate!dangerous!to!life!or!health!(IDLH)!concentration!and!the!EPA’s!inhalation!reference!concentration!(RfC)!that!estimates!the!level!of!continuous!inhalation!exposure!to!a!chemical!that!is!likely!to!have!no!risk!of!deleterious!nonCcancer!effects!during!a!lifetime!for!the!hazardous!pollutants!considered.!!!Even!if!methane!is!excluded!from!being!a!hazardous!pollutant,!in!March!2014!the!White!House!approved! a! strategy! to! reduce!methane! emissions,! that! the! EPA! is! supporting! along! with!proposing!various!voluntary!programs!for! reducing!methane!emissions.! !The!Government’s!goal!is!to!cut!methane!emissions!to!17%!below!2005!levels!by!2020.!!!!Pollutant+ OSHA++PEL+ NIOSH+IDLH+ RfC+Benzene! 3,19! 1595! 0,03!Hexane! 1800! 3880! 0,2!Ethylbenzene! 434! 3472! 1!Toluene!! 754! 1885! 5!Xylene!! 435! 3,900! !Table&5&Concentration&of&pollutants&in&the&air&according&to&different&entities.&All&in&mg/m

3.&Only&OSHA&is&regulatory.&&

Again,! EU! and! USA! have! different! approaches! on! dealing! with! organic! pollutants.! If! their!regulation!is!much!less!precise!than!the!one!about!organic!pollutants,!the!USA!shows!a!legal!effort! to! protect! the! environment! and! especially! human! health! from! these! “hazardous!pollutants”! as! individual! entities.! In! the! EU,! organic! pollutants! are! addressed! as! VOCs,!excluding!methane,!which!juggles!between!VOCs!and!GHG!legislation!without!being!directly!tackled.!In!one!way!or!another,!these!pollutants!are!nevertheless!taken!into!consideration!by!the!different!governments!and!in!fact,!measures!to!reduce!their!emission!are!put!into!place.!Table!6! !and!Table!7!collect! !some!of! the!most! important!actions! taken! in!EU!and!USA!to!!reduce!VOCs!and!methane!emissions!respectively.!Once!more,!California!being!the!core!of!air!pollution!in!the!USA,!its!proposed!measures!have!been!analysed!as!representative!for!the!country.!!!!!!!!!



Measures+to+reduce+emissions+from++VOCs+EU+ •! Consumer!products!containing!solvents!

Paints!and!vehicle!refinishing!industry!(Liebscher,!2000):!!C! Reduction!of!organic!solvent!content!by!using!lower!viscosity!resins!

leading!to!high!solid!paints.!!C! Replacement!of!organic!solvents!by!water,!leading!to!water!borne!

systems.!!

•! Chemical!Industry!(Markus!Amman!Klimont!Zbigniew,!Janusz!Cofala,!2000):!!

Production!processes!in!the!organic!chemical!industry:!!C! Reduction!of!vent!losses!and!implementation!of!inspection!programs!to!

prevent!equipment!leaks!!C! Use!of!addCon!techniques!like!thermal!and!catalytic!incineration.!

Storage!and!handling!of!chemical!products:!!C! Ensure!correct!storage!by!introducing!internal!floating!covers!and!

secondary!seals!!C! Implementation!of!vapour!recovery!units!to!limit!breathing!losses!(those!

that!happen!during!storage!due!to!expansions!and!contractions!resulting!from!temperature!and!barometric!changes)!!!

•! Oil!and!gas!industry!(Markus!Amman!Klimont!Zbigniew,!Janusz!Cofala,!2000):!!

Fuel!extraction!and!distribution:!!C! Implement!vapour!balancing!systems!to!limit!working!losses!(those!that!

happen!during!filling!of!tanks).!!C! Improve!ignition!systems!on!flares.!!

Refineries:!!C! Set!inspection!and!maintenance!programs.!

Stationary!Combustion:!!!C! Integrate! oxidation! catalysts! and! new! boilers! in! Commercial! and!

residential!combustion!!

USA+ (South!Coast!Air!Quality!Management,!2013)!offers!VOCCspecific!control!strategies!!within!a!bigger!strategy!aimed!to!meet!PM2,5!and!8Chour!O3!requirements.!

•! VOCs!reduction!to!achieve!PM!reduction:!!C! Reduce!emissions!from!underCfired!char!boilers!in!restaurants!which!

are!responsible!for!71%!of!VOC!emissions!in!restaurants.!Measures!put!forward!include!use!of!electrostatic!precipitators,!high!efficiency!particulate!arresting!filters!and!thermal!oxidizers.!!!

•! VOC!reduction!within!O3!reduction:!!From!coatings!and!solvent!use:!

C! Reduce!emissions!from!architectural!coatings!by!using!application!techniques!with!greater!transfer!efficiency!such!as!laser!paint!targeting!systems!(up!to!30%!increased!efficiency)!

C! Reduce!emissions!by!further!limitation!of!VOC!content!in!the!formulation!of!products.!!

C! Use!of!alternative!non!VOC!products!C! Requiring!use!of!lowCVOC!mould!release!products.!!!!

From!Petroleum!operations!and!fugitive!VOC!emissions:!!

Introduction!!


C! Reduce!emissions!from!the!venting!of!vacuum!trucks!through!use!of!control!technologies!such!as!carbon!adsorption!systems,!internal!combustion!engines,!thermal!oxidizers,!refrigerated!condensers!and!liquid!scrubbers.!!

C! Implementation!of!Leak!Detection!and!Repair!Programs!!!C! Using!lowCemission!connectors,!routine!leak!checks,!lowCemission!fixed!

liquid!level!gauges!in!liquefied!petroleum!gas!transfer!and!dispensing!activities.!!!

Table&6&Collection&of&measures&taken&in&the&EU&and&USA&to&reduce&VOCs&emissions.&&

!Measures+to+reduce+emissions+from+methane+gas!

EU++ •! European!Commission!(EC)!is!a!Global!Methane!Initiative!(GMI)!Member!and!encourages!MS!to!become!partners.!!!

•! Climate!and!Energy!Package:!!This!EU!initiative!addresses!all!GHG,!not!methane!individually!and!it!stands!upon!two!pillars!(Global!Methane!Initiative,!2013):!!

C! Revision!and!strengthening!of!the!Emissions!Trading!System!(EU!ETS)!which!used!to!focus!on!CO2,!N2O!and!PFCs!and!aims!to!include!more!GHG!gases.!EU!ETS!sets!a!‘cap’!or!limit!of!total!amount!of!certain!GHG!that!can!be!emitted!by!factories,!power!plants!and!other!installations!in!the!system.!These!then!receive!or!buy!emission!allowances!to!trade!between!companies!in!the!system.!Putting!a!price!on!emissions!saved!has!raised!GHG!emissions’!concern!to!company!boards!and!financial!departments.!Caps,!which!are!set!at!EU!level,!are!currently!reduced!1,74%!yearly!but!plans!are!to!reduce!it!2,2%!yearly!from!2021!onwards.!

C! An!Effort!Sharing!Decision!has!been!approved!to!assess!GHG!emissions!from!sectors!not!covered!by!the!EU!ETS!such!as!transport,!housing,!agriculture!and!waste.!Each!MS!has!agreed!to!bind!to!emissions!limitations!in!order!to!make!2020!GHG!emissions!from!non!ETS!sectors!10%!below!their!levels!in!2005.!MS!have!to!define!and!implement!national!policies!to!achieve!this!like!reducing!transport!needs,!promoting!public!transport!use,!more!efficient!heating!and!cooling!systems,!climate!friendly!farming!practices,!conversion!of!livestock!manure!to!biogas…!The!EU!offers!workshops!for!MS!to!share!best!practices!and!experience.!Up!to!today!four!workshops!have!been!held!in!Sofia,!Tallinn,!Warsaw!and!Madrid,!focusing!on!transport,!buildings!and!agriculture.!!!

USA+ •! GMI!Member!and!Leader!!!

•! Climate!Action!Plan:!Strategy!to!cut!methane!emissions!!Reducing!emissions!from!Landfill!sector:!

C! Update!currents!standards!for!municipal!solid!waste!landfills!C! Propel!landfill!gasCtoCenergy!conversion!through!voluntary!energy!

recovery!projects!at!landfills!within!the!Landfill!Methane!Outreach!Program.!!

C! Reducing!landfill!waste!!

Capturing!methane!emissions!from!Coal!Mining!sector:!!C! Reduce!waste!coal!mine!emissions!by!capturing,!selling!or!disposing!of!

the!waste!methane.!Technologies!are!to!be!determined.!!



C! Reducing!coal!mining!emissions!by!helping!the!industry!to!overcome!institutional,!technical,!regulatory!and!financial!barriers.!!

!Reducing!emissions!from!Agriculture!sector:!!

C! Livestock!manure!management!by!means!of!anaerobic!digestion!and/or!biogas!conversion.!!

C! Enhancing!the!deployment!of!biogas!systems!by!providing!financial!and!technical!assistance!to!interested!parties.!!!

Reducing!methane!emissions!from!Oil!and!Natural!Gas!sectors:!C! Applying!costCeffective!technologies!and!best!management!practices!to!

capture! methane! from! venting! and! leaks.! This! needs! equipment!upgrades!or!replacement,!process!or!operational!changes.!!!

Table&7&Collection&of&measures&taken&in&the&EU&and&USA&to&reduce&methane&gas&emissions.&&

While!the!USA!addresses!the!methane!problem!individually,!the!EU!still!considers!it!indirectly!through! the! GHG! package,! as! it! did! on! the! respective! legislation.! As! a! result,! measures!proposed! in! the!USA!seem! to!be!much!more!precise.!Measures! to! reduce!emissions! from!VOCs!are!quite!similar! in! the!EU!and!USAf! they!are!mainly! focused!on!structural!changes!(change!in!the!nature!of!products!used)!and!on!the!use!of!equipment!to!ensure!protection!in!processes! like! venting!and! filling.!Once!more,! the!USA! tends! to! insist! on!adoption!of! new!technologies!and!on!incentiveCbased!actions.!Differing!to!the!organic!pollutant!measures,!both!methane!and!VOCs!emissions!reduction!is!more!directed!to!voluntary!programs!rather!than!regulations.!!

1.3+ Conclusion++!After!all!the!aspects!discussed,!it!is!evident!to!note!that!air!pollution!is!a!worldwide!concern.!Pollution!related!to!the!traffic!sector!has!been!a!particularly!polemic!subject!recently!in!the!city!of!Madrid.!Of!the!measures!discussed!in!Table!2,!speed!restrictions!where!effectively!applied!in!February!2016,!use!of!public!transport!has!been!more!and!more!encouraged!(through!the!implementation!of!car2go,!BiciMad!and!the!20!€!flat!rate!for!the!public!transport!ticket!for!under!26!year!old!citizens!for!all!of!Madrid!public!transport!areas)!and!for!the!first!time!ever,!traffic!restrictions!where!considered.!In!fact,!only!2,18%!of!Spain’s!passenger!car!fleet!works!with!alternative!fuels!(fuels!different!from!diesel!or!petrol)!compared!to!the!4,94%!average!of!the!European! Union! (“Passenger! Car! Fleet! by! Fuel! Type! |! ACEA! C! European! Automobile!Manufacturers’!Association,”!n.d.).!This!realisation!and!the!recent!events!come!to!show!the!necessity!of!improving!the!country’s!air!quality!(and!specifically!the!one!of!its!capital!and!most!important!urban!area,!Madrid)!and!the!necessity!of!a!new!approach!on!dealing!with!behaviourCbased!measures!taken!in!this!field.!To!deal!efficiently!with!the!air!pollution!problem!a!deeper!study!must!be!carried!out!to!try!to!establish!a!relationship!between!the!three!main!aspects!of!pollution!considered:!the!problem!of!air!pollution!itself,!social!awareness!in!that!field!and!the!public! health! problem! it! generates,! health! protection! being! the! driving! force! of! pollutant!emission!reduction!legislation.!Effectively,!the!purpose!of!this!monography!will!be!to!search!for!any!existing!relationship!amongst!these!topics!in!the!city!of!Madrid.!!

!!!!!!!!!

Introduction!!


!!!!!!!!



2! STATE!OF!THE!ART!!!!The! purpose! of! this! chapter! is! to! identify! the! existing! studies! concerning! the! air! pollution!problem,!its!public!health!impact!and!its!social!awareness!as!well!as!any!bilateral!relationships!addressed.!Furthermore,!threeCdimensional!relationship!studies!will!be!searched!for!in!order!to!take!advantage!of!its!results,!test!them!and!even!improve!them.!!!

2.1+ Air+quality+related+studies+!Environmental!monitoring! is!necessary! to!generate!strong!evidence! for! the!development!of!effective!environmental!and!public!health!policies.!Effectively,! the!EU!2008/62/EC!Directive!requires!the!implementation!of!a!minimum!number!of!sampling!points!to!measure!pollution!on!fixed!points!and!encourages!the!application!of!numerical!models!to!better!assess!air!quality!by!obtaining!a!wider!geographical!scale!assessment!of!pollutants!and!therefore!to!create!more!effective!AQPs.!!!

2.1.1! Studies!using!the!static!approach!!As!a!result,!most!MS!have!put!into!place!models!that!take!into!account!processes!exclusively!influencing!air!quality!such!as!dispersion!and!deposition!of!air!pollutants! to!quantify! the!air!quality! impact!of!an!abatement!measure,!without!evaluating!any!other!effects! the!measure!might!have.!In!most!cases,!no!economic!or!healthCimpact!evaluation!of!the!measure!put!into!place!is!made!(Miranda!et!al.,!2015).!!!The! input! information! required! by! these! models! comprises! emission! measurements,!meteorological!variables!and!initial!boundary!conditions.!Traditionally,!the!emissions’!data!for!these!models!was!gathered!from!static!monitoring!sources!and!models!were!used!to!estimate!pollutant!concentrations! in!areas! that! the!stations!did!not!cover.!Most!models! in! the!AQPs!evaluated!by!(Miranda!et!al.,!2015)!used!Eulerian!Chemical!Transport!Models! (CTM)!while!fewer! used! Gaussian! plume! models.! Similarly,! meteorological! data! was! obtained! from!mesoscale!measurements!when,!in!a!typical!urban!environment,!the!effect!of!meteorological!events!in!air!pollution!depends!as!well!on!those!that!occur!at!a!micro,!local!and!regional!scale.!!These!models!all!fall!inside!the!traditional!static!approach!which!neglects!the!dynamic!aspect!of! the!air!pollution!exposure!problem.!However,! to!better!quantify!pollutant!concentration! in!areas! that! are! not! covered! by! monitoring! stations! but! also! to! achieve! better! exposure!assessment,!data!should!ideally!include!sources,!pathways!and!routes!of!pollution!along!with!meteorological!data!and!pollutant!concentration!(Steinle,!Reis,!&!Sabel,!2013).!Additionally,!fixed! monitoring! stations! cannot! measure! very! high! but! temporarily! and! spatially! bound!pollutant!concentrations,!referred!to!as!pollution!hotspots!(Kumar!et!al.,!2015).!The!available!technology! in! fixed! monitoring! stations! alone! seems! therefore! unable! to! provide! highCresolution!information!that!is!required!to!improve!air!quality!assessment.!!!

2.1.2! Studies!using!the!dynamic!approach!!Indeed,! thanks! to! new! technical! and! electronical! developments,! exposure! assessment! is!slowly! turning! into!personal! exposure!assessment,! giving!a!wider!approach! to!air! pollution!studies:!this!is!known!as!the!dynamic!approach.!Studies!in!the!literature!introduce!the!dynamic!factor! either! by!measuring! pollutant! concentrations! using!mobile!monitoring! stations! or! by!including!a!new!type!of!input!data:!individual’s!travelCpatterns.!!!Fixed!monitoring!stations,!when!available!in!an!urban!environment,!are!sparsely!spread!across!the! city! (Kumar! et! al.,! 2015f!Moltchanov! et! al.,! 2015).! This!means! that! no! highCresolution!

State!of!the!Art!!


(accurate!to!the!metre)!information!can!be!obtained!with!their!data!because!even!if!models!do!estimate!the!air!quality!in!other!areas,!the!needs!of!data,!computing!facilities!and!input!details!to!obtain! this! level!of!resolution!make! it!an! inaccurate!and!sometimes! impossible!approach!(Kumar!et!al.,!2015).!To!overcome!this!obstacle!and!achieve!high!resolution,!many!cities!are!testing!mobile!laboratories.!Mobile!air!pollution!monitoring!networks!go!from!public!or!private!vehicles!to!aircrafts,!passing!through!personal!devices!(Swiss!Federal!Institute!of!Technology!in! Zurich,! n.d.).! This! has! been! made! possible! thanks! to! technological! progress! and!development! of! mobile,! lowCcost! microCscale! sensing! devices.! Indeed,! while! air! pollutant!analysers!used!to!be!big!and!expensive!(tenths!of!thousands!of!pounds),!current!developments!can!cost!under!hundredths!of!pounds!and!are! lightweight!and!compact! .!Whether! they!are!optical! or! chemical! gas! sensors,! they!are!paired!with! communication!devices! that! allow! to!gather!realCtime!air!quality!data!by!sending!data!to!the!cloud!or!to!a!dataCprocessing!device!through!WiCFi,!GMS,!Bluetooth!(Kumar!et!al.,!2015)…!!!This!technology!is!already!in!use!in!meteorological!networks!like!WeatherBug!in!the!USA!and!in!air!quality!services!that!use!hybrid!modelling!like!airTEXT!in!London!(Kumar!et!al.,!2015).!However,! many! research! programmes! are! using! sensor! networks! to! evaluate! their!performance!both!in!fixed!and!mobile!air!quality!monitoring.!In!Europe,!the!most!important!one!might!be! the!OpenSense!Project! launched!by! the!Swiss!Federal! Institute!of!Technology! in!2013.!This!project!was!fully!deployed!in!Zurich!and!is!currently!in!deployment!in!Lausanne.!It!consists! on! placing! sensor! boxes! on! top! of! trams,! buses! and! electric! cars,! equipped!with!wireless!communication!technology.!The!sensors!collect!ultrafine!particle!concentration!data!used! to!generate!pollution!maps! that!are!made!available! in! the!project’s!mobile!application!(Swiss!Federal! Institute!of!Technology! in!Zurich,!n.d.).!Further!demonstration!studies!have!been!carried!out! in!other!European!cities! like!Cambridge!(UK),!Valencia!(Spain)!and! in! the!African!city!of!Lagos!(Nigeria)!(Kumar!et!al.,!2015).!In!the!USA,!NASA’s!Deriving!Information!on!Surface!Conditions! from!Column! and!Vertically!Resolved!Observations!Relevant! to! Air!Quality!(DISCOVERCAQ)!combines!aircrafts!and!grounded!mobile!stations!to!evaluate!nearCsurface!pollution!since!2011!in!Houston,!Texas!(NASA,!2011).!In!Massachusetts,!an!air!quality!assessment! study! used! a! Tufts! Air! Pollution! Monitoring! Laboratory! (TAPL)! to! obtain!measurements!of!local!scale!(with!a!20!metre!resolution)!pollutant!concentrations.!The!TAPL!is! a! converted! recreational! vehicle! that! was! driven! very! slowly! and! carried! fastCresponse!monitoring!instruments!(Kumar!et!al.,!2015).!In!the!Near!East,!a!study!conducted!in!Israel!used!a! network! of! miniature! wireless! sensors! that! registered! NO2! and! TVOC! levels! every! 20!seconds!and!O3!levels!every!minute!(Moltchanov!et!al.,!2015).!!Existing!studies!applying!sensor! technology!are!mainly!research!projects!certainly!because!there!is!still!no!legislation!about!the!usability!of!the!devices!employed.!Once!the!field!trials!are!over! and! legislation! is! approved,! surely! developers! will! work! with! municipal! agencies! to!integrate!the!use!of!sensors!in!official!air!quality!assessment!(Kumar!et!al.,!2015).!!!However,! sensors! are! also! used! by! individuals! or! communityCled! networks! to! measure!personal!exposure!(Kumar!et!al.,!2015).! Indeed,! there! is!a! range!of!commercially!available!sensors!for!personal!use!that!allow!to!obtain!discrete!measurements!of!concentrations!of!a!pollutant!as!closely!as!possible!to!a!person’s!breathing!zone.!While!this!data!is!of!no!further!relevant!use,!personal!sensors!used!within!communityCled!networks!do!have!a!wider!sense!of!being.!!Founded!in!New!York!City!and!Amsterdam,!Air!Quality!Egg!is!an!individual’s!sensor!network.!Each!individual!purchases!an!“egg”!or!personal!air!quality!sensor!to!assess!air!quality!in!their!immediate!surroundings,!but!the!information!is!shared!with!other!users.!!!Other!existing!studies!have!opted!for!keeping!fixed!site!air!quality!monitoring!but!introducing!individual!travelCpatterns.!Initially,!travelCpatterns!where!obtained!through!questionnaires!like!time! activity! diaries! (TADs)! or! mathematical! models.! Studies! using! the! concept! of!microenvironment!(ME)!were!also!quite!popular.!MEs!are!the!home,!the!place!of!work!and!a!few! other! frequent! locations! of! an! individual.! Knowing! these!MEs’! locations,! stationary! air!



quality!monitors!are!installed!in!those!key!spots!and,!based!on!a!fixed!route!for!the!individual,!personal! assessment! is! estimated! (Steinle! et! al.,! 2013).! More! recent! studies! used! GPS!tracking!system! to! locate! individuals! (Steinle!et!al.,!2013)!but! these!studies!were! limited! in!number!of!participants!and!quite!costly!(Dewulf!et!al.,!2016f!Gariazzo,!Pelliccioni,!&!Bolignano,!2016).!In!order!to!conduct!large!scale!population!studies,!GPS!tracking!is!neither!practical!nor!economic! and! therefore,! these! studies! have! explored! the! possibility! of! using! positioning!information!from!mobile!cellular!networks!that!is!less!accurate!than!GPS!data,!but!can!include!far!more!participants.!!!Mobile! phone! data! is! a! passive!mobile! positioning! system! that! provides! a!mobile! phone’s!position!based!on!the!cell!architecture!of!mobile!networks.!Indeed,!mobile!networks!comprise!different!cell!stations!containing!antennae!that!cover!a!specific!and!unique!geographical!area.!Whenever! a! transaction! is! made,! the! mobile! phone! exchanges! information! with! the! cell!governing!that!area.!Like!so,!the!mobile!phone!is!registered!in!a!certain!area!and!its!position!is!passively!obtained.!The!position!of!a!mobile!phone!is!updated!when!it!enters!in!a!new!cell’s!area!or!automatically!updated!every!3!hours!or!so!(Dewulf!et!al.,!2016).!While!the!accuracy!and!resolution!of!the!tracking!data!is!significantly!below!GPS!data,!it!allows!to!access!a!larger!amount! of! population.! The! positioning! data! is! then! linked! to! the! individual’s! personal!anonymous! data! in! order! to! calculate! personal! assessment.! However,!mobile! phone! data!registered!by!cells!is!information!owned!by!telecom!operators!and!hence!does!not!cover!all!individuals.!Most! recent! studies! in! this!domain! include!a!study! in!Belgium,!using! individual!location! data! from! the! telecom! operator! Proximus! that! has! a! 41%!market! share,!while! air!quality!data!was!modelled!(Dewulf!et!al.,!2016).!In!another!study!carried!out!in!Rome,!mobile!phone! data! was! combined! with! pollutant’s! concentration! and! flow! reconstruction! through!integrated!model!systems,!including!turbulence!parameters!(Gariazzo!et!al.,!2016).!In!a!study!carried! out! in! California,! mobile! phone! data! was! provided! by! Google! and! pollutant!concentration!was!measured!by!sixty!air!samplers!located!in!49!sites!for!the!purpose!of!this!study!(Su,!Jerrett,!Meng,!Pickett,!&!Ritz,!2015).!!!

2.1.3! Main!shortcomings!of!the!existing!studies!!!Comparing! results! from! fixedCstations! and! personal! monitoring! shows! that! there! are!“substantial!differences!in!concentration”!and!thus!there!should!be!“a!preference!for!the!use!of!personal!monitoring!techniques!to!collect!reliable!exposure!information”!(Steinle!et!al.,!2013).!Therefore,!the!main!shortcoming!of!the!existing!studies!is!the!use!of!fixed!monitoring!stations!as!input!data!on!its!own.!Moreover,!the!EU!Directive!only!recommends!the!use!of!models!to!better!assess!air!quality,!therefore!some!MS!might!not!even!build!such!models.!&&

After! researching! the! literature,! it! can! be! concluded! that! air! pollution! related! studies! are!basically!led!by!the!Environmental!or!Government!Authorities!to!generate!effective!abatement!measures! for! pollutants! concentrations.! However,! most! of! these! disregard! any! kind! of!economic!evaluation!or!integrated!assessment!(Miranda!et!al.,!2015).!Integrated!assessment!of!abatement!measures!takes!into!account!the!measure’s!environmental!effects,!but!also!its!health! impact,! its! implementation! costs! and! economic! quantification! of! the! damages! and!benefits!it!introduces.!Out!of!all!the!AQPs!reviews!by!(Miranda!et!al.,!2015),!only!the!Urban!Scale!Integrated!Assessment!Model!(USIAM)!in!the!UK!and!the!Air!quality!modelling!in!Urban!Regions! using! an! Optimal! Resolution! Approach! (AURORA)! are! integrated! assessment!models.!!Moreover,!new!practices! in! the!air!quality! field!–!namely!sensing! technology!and! individual!positioning!–!are!excluded!from!official!assessment!techniques!due!to!the!lack!of!legislation!concerning!its!usability.!In!order!for!this!to!happen,!sensors!will!have!to!improve!their!sensibility!considerably.! Indeed,! most! sensors! are! accurate! to! measure! hundreds! of! ppb,! but! most!pollutants’!concentrations!are!underneath!(Kumar!et!al.,!2015).!!!

State!of!the!Art!!


Even!if!integrated!assessment!is!not!yet!popular!in!AQPs,!many!studies!relating!air!pollution!to!health!impacts!have!been!led!and!will!be!discussed!in!the!next!section.!!!!

2.2+ Air+quality+and+its+health+effect+studies++!Epidemiological! studies! relating!air!pollution! to!mortality!and!morbidity!are!of!a!very!varied!nature!and!quite!abundant.!When!analysing!the!existing!studies,!many!parameters!like!type!of!study,!population!group,!pollutant!and!source!of!pollution!data,!time!of!exposure,!geographical!location!and!scale!or!health!impact!and!health!effect!of!interest!differ.!Furthermore,!mainly!for!studying! organic! pollutant! effects,! but! also! in! certain!PM!effects! studies,! these! have! been!carried!out!in!animals!and!in!vitro.!!!

2.2.1! Type!of!study!!!Two!types!of!studies!appear!to!be!the!most!popular:!cohort!studies!and!timeCseries.!To!carry!out! cohort! studies! individuals!are! selected!and! followed!over! time.!Panel! studies!are!used!mainly! for!morbidity! studies! and! their!main! advantage! is! to! give! insight! on! how! individual!characteristics!affect! the!results!of! the!study.!The!source!of! information!for! these!studies! is!usually!a!questionnaire!filled!in!at!enrolment!concerning!sex,!age,!weight,!height,!educational!level!and!health!history!(Lepeule,!Laden,!Dockery,!&!Schwartz,!2012)!and!posterior!follow!up,!for!example!by!means!of!activity!diaries!and!medical!checkCups.!TimeCseries!studies!carry!out!an! analysis! of! count! data:! they! examine! counts! of! a! certain! health! effect! in! response! to!variations! of! pollutant! concentration.! These! studies! require! obtaining! data! from! Hospital!Systems!instead!of!gathering!it!from!individuals!and!are!chosen!for!all!mortality!related!studies.!!!!

2.2.2! Population!groups!!!While!many!studies!consider!population!of!all!ages,!other!studies!focus!on!population!groups!that!have!been!determined!at!risk.!Studies!exist!for!children!under!5,!like!the!Pollution!Effects!on!Asthmatic!Children! in!Europe! (PEACE)! conducted! in! 1993! through! 1994! or! the! project!estimating! the!Environmental!Burden!of!Disease!(EBD)!carried!out!by!(Ostro,!2004),!which!aimed! to! find! the! number! of! causes! of! premature! mortality! and! DALYs! from! respiratory!diseases!attributed! to!short! term!exposure! to!PM10! in!children!under!5.!Likewise,!pregnant!women! are! considered! population! at! risk! and! in! 2007,! Women’s! Health! Initiative! (WHI)!concluded!a!study!that!had!followed!a!cohort!of!more!than!65!000!postmenopausal!women!since!1994.!Also!in!2007,!a!Swedish!cohort!study!of!250!000!construction!workers!with!PM!occupational!exposure!was!conducted.!Population!groups!of!people!that!already!suffer!from!a!certain! health! effect! that! air! pollution! could! potentially! exacerbate! like! asthma! are! also!considered!(PEACE).!!!

2.2.3! Pollutants!studied!and!source!of!data!!Most!past!studies!evaluate!single!pollutants!and!their!health!effects.!Effectively,!in!the!Estudio!Multicéntrico!Español! de!Contaminación!Atmosférica! y!Mortalidad! (EMECAM),! regressions!were!made!for!each!pollutant!and!each!cause!of!mortality.!Although!this!practice!is!not!ideal,!since!covariation!is!usual!amongst!pollutants,!concentrations!of!a!certain!pollutant!are!chosen!as!markers!of!outdoor!air!pollution.!Indeed,!PM!tends!to!be!a!popular!marker.!Not!only!does!it!present!the!most!consistent!associations!with!mortality!and!morbidity,!but!its!monitoring!is!also!expanded!worldwide.!This!does!not!mean!that!no!associations!have!been!established!for!other!pollutants!such!as!O3,!SO2,!CO,!NO2!(Ostro,!2004).!Important!studies!investigating!around!PM!are!the!Harvard!Six!Cities!Study!(HSCS)!in!1993,!which!concluded!that!risk!of!death!in!high!PMCpolluted!areas!was!26%!larger!than!lower!pollution!areasf!the!American!Cancer!Society!(ACS)!Study!in!1995!which!quantified!the!same!death!risk!at!17%f!and!again!in!2002!the!ACS!



was!the!first!study!to!show!statistically!significant!association!between!fine!particles!and!lung!cancer!(Lepeule!et!al.,!2012).!!!The!pollutants!concentration!is!usually!gathered!from!monitoring!stations!or!model!estimates.!In! the! HSCS,! monitoring! sites! were! specifically! placed! to! be! representative! of! the! local!population!exposure! level! (Ostro,!2004).!However,!as!commented!before,!new!sources! for!pollutant!monitoring!are!on!the!rise!but!fully!representative!studies!using!personal!monitoring!exposure!have!not!been!completed!yetf!all!that!has!been!done!are!pilot!studies!mainly!due!to!the!economic,!time!and!labour!needs!they!imply!(Steinle!et!al.,!2013).!!!

2.2.4! Time!of!exposure!!Health!effects!from!pollutants!have!shown!to!be!different!according!to!the!time!of!exposure.!ShortCterm!studies!are!done!comparing!daily!counts!of!mortality!or!hospital!admissions!for!the!health!effect!studied!with!daily!changes!in!concentration!of!pollutants,!usually!obtained!from!a!24!hour!based!average.!Sometimes,! the!data!of!air!pollutant!concentration!used! is! the!one!gathered! the!during!previous!day.!LongCterm!exposure! is!a! less! common!addressed! issue!because!they!cannot!control!individual!risk!factors!such!as!cigarette!smoking!or!preCexisting!diseases!(Pope!III!et!al.,!2002).!!!!

2.2.5! Geographical!location!and!scale!of!the!studies!!Air!pollution!and!health!related!studies!have!been!carried!out!all!over!the!world.!However,!most!are!localised!in!the!USA!or!EU,!while!very!few!are!centred!in!Asia!and!elsewhere!(Ostro,!2004f!Wong,!VichitCVadakan,!Kan,!&!Qian,!2008).!Moreover,!existing!studies!cover!from!continental!scales!to!large!metropolitan!areas!and!multiple!cities!or!are!restricted!to!a!single!city.!!!Effectively,! the!National!Mortality,!Morbidity!and!Air!Pollution!Studies!(NMMAPS)! is!a!USACwide!study!carried!out!in!the!20!largest!metropolitan!areas!of!the!country!in!2000!by!the!Health!Effects!Institute.!It!aimed!to!determine!the!effects!of!PM10!alone!and!in!combination!with!other!gaseous!pollutants,!using!data!from!1987!to!1884.!Also!in!the!USA,!the!ACS!disposes!of!a!wide!population!database!collected!as!part!of! the!Cancer!Prevention!Study!(CPS)! that!has!been!analysed!for!many!studies.!Likewise,!the!NMMAPS’!dataset!is!available!to!download!and!many!studies!use!it,!applying!different!statistical!tools!and!sensitivity!analysis!to!extract!new!conclusions!(F.!Dominici,!Roger!D.!Peng,!Keita!Ebisu,!Scott!L.!Zeger,!2007f!Ren,!Williams,!Mengersen,!Morawska,!&!Tong,!2008f!Stylianou!&!Nicolich,!2009).!!!In! Europe,! continentalCscale! studies! have! also! been! run.! The! Air! Pollution! and! Health:! A!European!Approach! (APHEA)!study!was!carried!out! in! two!phases:!APHEAC2!studies!both!mortality!and!hospital!admissions!in!29!and!8!cities!for!43!and!38!million!people!respectively.!From!June!2008! to!June!2010,! the!European!Study!of!Cohorts! for!Air!Pollution! (ESCAPE)!investigated!the!long!term!effects!of!air!pollution!on!human!health!in!36!European!areas.!Dating!2008C2011!and!involving!60!scientists,!the!Aphekom!project!conducted!an!inCdepth!update!of!the!impact!of!air!pollution!on!health!in!25!European!cities.!The!Aphekom!project’s!ultimate!goal!is!to!help!make!better!informed!decisions!regarding!air!pollution,!and!part!of!the!study!aimed!to!evaluate!the!efficiency!of!policies!designed!to!reduce!pollutants.!!!SmallerCscale!studies!are!however!much!greater!in!number!and!even!if!US!and!EU!studies!are!still!predominant,!multi!and!singleCcity!studies!are!also!conducted!in!other!parts!of!the!world.!According!to!(Pope!et!al.,!2006),!since!the!early!1990s,!over!100!research!articles!linking!shortCterm!exposure!to!air!pollution!and!mortality!studies!have!been!published,!most!of!them!being!singleCcity!time!series!studies.!Until!1997,!multiCcity!time!series!studies!were!very!rare.!In!the!early!2000s!studies!of!6,!10!and14!US!citiesf!8!and!9!Californian!citiesf!3!Australian!citiesf!9!French!citiesf!7!Korean!cities!and!13!Japanese!cities!were!carried!out,!while!metaCanalysis!from!existing!singleCcity!studies! from! the!1990s!were!also!overseen! (Pope!et!al.,!2006).! In!

State!of!the!Art!!


Spain,!the!EMECAM!project!(1992C1995)!covered!14!Spanish!cities!including!Madrid!and!run!regressions!for!different!pollutants!and!different!causes!of!mortality.!!!

2.2.6! Health!effects!of!interest!!Finally,! the!majority! of! existing! studies! focus! on! the! relationship! between!mortality! and! air!pollution,! while! morbidity! seems! to! be! less! popular! (Ostro,! 2004).! Within! mortality! and!morbidity,!the!cause!of!death!or!hospital!admission!is!also!taken!into!account.!Mortality!for!all!causes!is!analysed,!but!more!specific!causes!are!also!studied!both!for!mortality!and!morbidity.!Until! the!Monitoring! Trends! and!Determinants! in!Cardiovascular!Disease! (WHO!MONICA)!study’s!results!in!Germany!led!to!link!air!pollution!and!cardiovascular!disease,!studies!focused!on!the!more!evident!health!effects!of!air!pollution:!respiratory!and!circulation!issues.!After!that,!studies! have! considered! from! cardiovascular,! respiratory! and! circulation! issues! as! health!effects! to! more! specific! diagnosis.! The! NMMAPS! collected! mortality! from! all! causes!(accidental!and!nonCaccidental),!from!cardiovascular!disease,!respiratory!issues,!pneumonia!and!chronic!obstructive!pulmonary!disease.!The!ACS!focuses!on!the!effect!of!air!pollution!in!lung! cancer,! as! does! the! ESCAPE! project.! Asthma! is! also! a! recurrent! morbidity! cause!analysed.!!!

2.2.7! Common!methodology!!!The! first! and!most! used! statistical! approach! for!mortality! evaluations!was! a!Poisson! autoCregression!since!mortality!is!a!rare!event!that!is!well!described!by!such!distribution.!Wishing!to!make!better! estimations! and! control! the!main! confounders! (temperature,! day! of! the!week,!season),!other!statistical!tools!are!used.!General!Additive!Models!(GAM)!using!non!parametric!smoothing! were! another! popular! tool! in! the! late! 1990s! because! they! enabled! fitting! of!seasonality!and!time!trends,!along!with!association!to!weather!variables.! In!2002,! the!most!used! software! for! developing!GMAs!was! known! to! have! inadequate! default! settings! in! its!iterative!process,!which!caused!a!reanalysis!of!many!studies.!These!applied!more!rigorous!convergence!criteria! in!GMA!or!alternative!parametric!smoothing!approaches!(Ostro,!2004f!Pope!et!al.,!2006).!Cox!regressions!were!also!used!in!some!studies!(ESCAPE!project).!!!

2.2.8! Main!shortcomings!of!the!existing!studies!!There!is!a!vast!body!of!work!concerning!epidemiological!studies!related!to!air!pollution!that!link! very! specific! health! effects! to! particular! pollutants.!However,!many! studies! lack! of! the!necessary! scientific! evidence! to! be! fully! recognised! (Istamto,! Houthuijs,! &! Lebret,! 2014).!Indeed,!there!are!a!lot!of!uncertainties!regarding!these!studies.!!!For!instance,!an!issue!with!short!term!exposure!mortality!studies!is!that!they!do!not!take!into!account! preCexisting! diseases! (Ostro,! 2004).! Adding! to! that,! morbidity! studies! are! usually!based!on!hospital!admissions,!disregarding!visits! to!medical!practices! that!do!not!need!an!overnight!stay!and!of!course!completely!ignoring!symptoms!and!minor!discomforts.!However,!by! taking! into! account! these! “predictors”! of! hospital! admissions,! models! could! effectively!establish!a!relationship!between!health!effects!and!air!pollution!that!went!beyond!causality,!maybe! reaching! prediction! of! health! care! needs! and! establishing! more! efficient!recommendations!to!preserve!health.!!!Also,! air! pollution! models! are! confronted! to! a! lot! of! randomness.! The! concentration! of! a!pollutant!in!a!given!location!depends!on!complex!environmental!processes!that!are!not!trivial!to!predict,!like!atmospheric!flow!conditions!(Kumar!et!al.,!2015).!Moreover,!these!models!are!built! on! data! provided,! until! now,! by! fixed! monitoring! stations! that! are,! as! it! has! been!mentioned,!quite!expensive!and!quite!inefficient!at!measuring!personal!exposure,!which!is!key!in!obtaining!reliable!results!in!epidemiological!studies!(Steinle!et!al.,!2013).!Relying!on!these!



networks!as!the!only!source!of!air!quality!data!makes!it!impossible!to!carry!out!studies!in!poorer!countries,!particularly!in!developing!countries,!where!the!pollution!crisis!strikes!hard!and!health!outcomes!are!devastating.!Indeed,!while!countries!in!North!America!and!Europe!–!excluding!Albania,!Montenegro!and!Bosnia!and!Herzegovina,!are!all!considered!to!have!full!coverage!monitoring!by!(World!Air!Quality,!2015),!only!52%!of!countries!in!Asia!are!fully!covered,!27%!in!the!Middle!East,!25%!in!Latin!America!and!only!2!countries!in!Africa.!This!might!be!one!of!the!reasons!why!epidemiological!studies!are!geographically!concentrated!in!the!USA!and!EU!(Wong! et! al.,! 2008).! Yet,! in! countries! that! do! have! monitoring! networks,! not! all! common!pollutants!defined!by!the!EPA!are!measured!and!data!is!not!always!easily!accessible.!Finally,!pollutants!are!not!independent!from!one!another,!e.g.!!NOX!and!VOCs!are!O3!precursors,!and!therefore! it! is! hard! to! attribute! health! impacts! to! a! specific! pollutant.! Indeed,!most! studies!concentrate!on!PM!and!O3!as! “markers”! for!air!quality.!This!practice!might!mask! important!health!effects!produced!by!other!pollutants.!!!Concerning!cohort!studies,!they!rely!on!the!collaboration!of!the!participant!and!produce!smaller!datasets.! Having! access! to! individual! characteristics!without! the! need! for! the! individual! to!engage! himself! in! the! activity!would! allow! bigger! datasets! and! it! would! avoid! participant’s!dropouts.!!!All! of! these! limitations! push! researches! to! find! new!ways! of! assessing! air! quality,! without!having!to!rely!exclusively!on!monitoring!stations!(Mei,!Li,!Fan,!Zhu,!&!Dyer,!2014).!As!it!has!already!been!stated,!these!new!sources!of!information!include!sensors!and!locating!systems.!However,!available!studies!using!them!are!still!research!projects!that!focus!on!their!appliance!in!air!quality!assessment!exclusively,!overlooking!to!link!the!results!to!health!impacts.!!!

2.3+ Air+quality+and+social+awareness+studies++!The! first! important! effort! to! increase! social! awareness!of! air! pollution! problems!was!made!between!the!1960s!and!1970s!(Bickerstaff!&!Walker,!2001f!Bickerstaff,!2004).!Many!studies!were!carried!out,!notably!in!the!UK!and!the!USA!–!with!the!State!of!California!leading!the!way,!where!major!episodes!of!smog!occurred.!These!studies!comprised!mainly!attitudinal!surveys!and!tackled!the!issue!through!a!psychological!approach.!However,!there!was!little!followCup!of!these!studies!until! the!late!1990s!and!early!2000s,!when!the!issue!was!looked!upon!with!a!socioCcultural! approach! rather! than! a! psychological! one.! Since! then,! air! pollution! related!studies!have!focused!on!scientific!and!medical!research,!pushing!the!social!awareness!of!the!problem!into!the!background.!Having!said!that,!it!must!also!be!said!that!in!the!past!two!years!there!has!been!an!increased!concern!in!ecological!and!environmental!issues,!not!particularly!centred! in! air! pollution,! but! certainly! including! it.! This! section! aims! therefore! to! collect! the!existing!studies!and!their!main!conclusions!on!social!awareness!of!the!air!pollution!problem.!The!sources!of!air!pollution!risk!perception!by!the!general!public!will!be!analysed!first,!to!then!move!onto! the!analysis!of! the!sources,!contents!and!message!efficiency!of! the! information!related!to!air!pollution!provided.!Finally,!the!leap!between!awareness!and!actual!concern!or!between!information!and!effective!action!will!be!considered.!!!!

2.3.1! Sources!of!air!pollution!risk!perception!!!Risk!perception! is!defined!by!(Bickerstaff,!2004)!as! “people’s!beliefs,!attitudes,! judgements!and!feelings,!as!well!as!the!wider!cultural!and!social!dispositions!they!adopt!towards!hazards!and!their!benefits”.!In!other!words,!how!serious!does!the!lay!public!think!the!air!pollution!issue!is?! Air! pollution! has! risks! that! can! be! classified! as! urban! air! pollution! risks,! industrial! air!pollution!risks!and!climate!change!risks.!In!all!of!these!three!fields,!studies!agree!that!there!is!a!significant!difference!between!the!objective!or!statistical!risk!issue!defined!by!experts!and!the!perceived!or!subjective!risk!of!the!lay!public!(Bickerstaff,!2004f!Murch,!1971f!Wakefield,!Elliott,!Cole,!&!Eyles,!2001).!!!

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Indeed,!while! experts! rate! air! pollution! risks! based! on! probability! of! fatality,! the! lay! public!evaluates!the!risk!of!an!activity!by!a!combination!of!different!processes.!The!main!source!of!air!pollution!risk!perception!is!undoubtedly!direct!experience.!Additional!relevant!sources!are!indirect! experience,! psychological! and! socioCcultural! factors! as!well! as! awareness! through!information!provided!about!air!pollution!risks.!!!It! is! widely! agreed! that! direct! experience! is! the! necessary! solid! foundation! to! build! a! risk!perception!in!an!individual.!It!is!more!important!in!the!risk!perception!process!than!scientific!evidence!or!any!kind!of!secondary!information.!Indeed,!if!available!information!is!not!backed!up!by!personal!empirical!evidence,!it! is!generally!dismissed!as!irrelevant.!Direct!experience!comprises! all! physical! factors! such! as! sensory! evidence! and! associated! health! effects.!Sensory!evidence!refers!to!visual!evidence!like!depositional!evidence!in!the!form!of!dust,!dirt!or! pollution! hazes,! or! visible! effects! on! the! environment! such! as! the! colour! of! growing!vegetation!and!to!olfactory!evidence!like!the!presence!of!odours!related!to!specific!sources!such!as!car!fumes!or!local!industrial!emissions!but!also!to!the!lack!of!positive!odours!such!as!that!from!plants!or!grass.!Tangible!and!observable!features!of!air!pollution!play!effectively!a!crucial!role!in!risk!perception:!as!stated!in!(Bickerstaff!&!Walker,!2001),!when!particulate!matter!concentration! increases,! there! is! an! increasing! expression! of! concern! about! air! pollution!however!this!is!not!as!straight!forward!with!gaseous!pollutants,!which!only!raise!awareness!if!when!and!if!they!reach!levels!that!generate!odours.!Health!associated!impacts!are!also!a!big!source!of!awareness:! !also! in! (Bickerstaff!&!Walker,!2001)!a!positive! relationship!between!health!related!complaints!and!high!concentration!of!pollutants! is!found!with!a!χ! test!at!99%!confidence.!But,!although!it!is!commonly!accepted!that!air!pollution!does!have!adverse!effects!on!health,!precise!links!to!health!issues!are!quite!unclear!among!the!lay!public.!This!will!be!discussed! in! more! depth! in! the! following! section! that! aims! to! review! the! body! of! work!elaborated!concerning! the!social!awareness!not!of! the!air!pollution!problem! itself!but!of! its!health!impacts.!!!Indirect! experience,! though! not! nearly! as! strong! as! direct! experience,! is! also! a! source! of!awareness! of! the! air! pollution! problem.! This! may! include! historical! legacy,! interpersonal!interactions! and! conversations.! The! study! carried! out! by! (Howel,! Moffatt,! Bush,! Dunn,! &!Prince,!2003)!compares!the!public!views!of!air!pollution!in!two!urban!localities!in!North!East!England.!While!Teesside!is!filled!with!heavy!industries!and!air!pollution!has!been!on!the!city’s!agenda! for! decades,! Sunderland! is! home! to! lighter! industry! and! shows! no! historical! air!pollution!concern.!One!of!the!study’s!conclusions!is!that!“place!stigma”!plays!an!important!role!in!air!pollution!risk!perceptions.!(Bickerstaff,!2004)!also!stresses!the!role!of!stigma!created!by!historical! legacy:!some!populations!are!submitted!to!psychoCsocial!consequences!of! the!air!pollution!problems!without!the!scientific!establishment!of!an!actual!human!or!environmental!risk!–!stigmatisation!of!the!place!seems!to!be!the!cause.!Informal!experience,!or!second!hand!experience!introduces!local!knowledges,!social!networks!and!other!interpersonal!channels!as!shapers!of!the!development!of!a!specific!air!quality!perception.!!!Psychological!studies!claim!that!lay!public!evaluates!risks!based!on!two!factors!that!scientists!have!labelled!as!the!“dread”!factor!and!the!“unknown”!factor!(Bickerstaff,!2004).!Hazards!are!seen!as!harmful!when!they!are!dreaded!(the!risk! is!perceived!as!uncontrollable,!potentially!catastrophic,!dangerous!to!future!generations!and!involuntary)!and!when!they!are!unknown!(it!is!estimated!that!the!scientific!knowledge!about!the!risk!is!not!developed,!the!risk!is!not!familiar!or!present!in!daily!life).!When!this!is!applied!to!air!pollution!issues,!it!explains!why!respondents!of!the!surveys!carried!out!by!many!studies!don’t!seem!to!take!them!as!seriously!as!the!experts!do.! Indeed,! the! use! of! cars! and! motorcycles! or! the! presence! of! industrial! activities! is!sometimes! anchored! in! people’s! daily! lives! so! the! risk! is! neither! unknown! nor! dreaded,!resulting!in!a!very!low!risk!perception.!!!However,!the!psychological!approach!is!being!replaced!by!the!socioCcultural!approach!mainly!due!to!the!fact!that!the!former!considers!lay!public!as!a!unique!entity,!while!the!latter!sees!the!



necessity! to! form! groups! according! to! different! socioCcultural! factors! that! involve! fields! of!knowledge!such!as!geography,!sociology!and!anthropology.!!!Place!or! locality! is!an! important! factor!when!establishing!an!air!pollution! risk!perception.! In!most!existing!studies,!respondents!view!areas!as!more!polluted!when!there!is!either!proximity!to!pollution!sources!(mainly!roads!and!motorways,!but!also!industry)!or!when!there!is!a!high!population!density!(city!centres).!Of!course!polluter!concentration! is! important!to!air!quality,!but!people!seem!to!ignore!the!environmental!processes!of!pollution!dispersion!that!makes!of!the!air!pollution!problem!a!worldwide!concern.!!!Adding!to!that,!there!is!an!observation!that!the!higher!the!socioCeconomic!status,!the!lower!the!concern!for!local!air!quality.!Indeed,!people!with!socioeconomic!advantages!tend!to!see!the!world! as! “less! dangerous”.! Wealthier! communities! associate! air! pollution! to! lower! socioCeconomic! classes! living! close! to! industry! (Bickerstaff! &! Walker,! 2001f! Bickerstaff,! 2004).!However,!this!different!views!of!the!air!pollution!problem!are!not!purely!socioCcultural:!studies!carried!out!in!the!UK!and!North!America!reveal!there!is!an!inequality!in!the!location!of!pollution!and!technological!hazards!that!seem!to!be!concentrated!near!poor!and!marginal!communities.!Also,!air!quality!perception!is!linked!to!certain!elements!like!space,!greenery!or!cleanliness:!wider,!cleaner!streets!with!vegetation!are!viewed!as!having!higher!air!quality!than!narrower!streets! filled! with! litter.! This! is! therefore! closely! linked! to! the! financial! situation! of! the!populations! living! in! the! communities! and! indeed,! there! will! be! a! higher! level! of! physical!management!of! the!neighbourhood!where! there! is!higher! financial!power.!As!(Bickerstaff!&!Walker,!2001)!puts!it,!“deteriorating!the!social!and!physical!environment!of!a!neighbourhood!will!contribute!to!people’s!concern!for!air!pollution”.!Other!less!relevant!socioCcultural!factors!that! are! not! as! commonly! supported! by! different! studies! as! the! socioCeconomic! ones! are!education!level,!gender!and!age.!Though!it!seems!sensible!to!assume!that!education!would!play!a!major!role!in!risk!perception!of!air!pollution!problems,!the!fact!that!this!perception!relies!mainly! on! direct! experience! makes! it! play! a! secondary! role.! Of! course,! higher! levels! of!education!mean!higher!understanding!of!the!objective!side!of!the!problem!and!higher!demand!for! further! comprehension! (Murch,! 1971).! Nevertheless,! information! about! air! pollution!problems,! as! it! will! be! developed! in! following! sections,! is! not! a! widely! spread! source! of!awareness,! and! so,! insisting!again!on! the! importance!of! practical! experience!of! the! issue,!differences!in!public!awareness!based!on!education!fall!into!the!background.!It!is!sometimes!mentioned!that!women!seem!to!be!more!active!and!aware!of!certain!social!problems!(Howel!et!al.,!2003)!:!indeed,!(Howel!et!al.,!2003)!claims!that!more!women!were!found!to!report!air!quality!concerns!than!men!in!Canada!but!also!notes!that!in!particularly!“stressed”!communities!gender!differences!disappear! in! this! field.!Age!however,! is!barely!mentioned! in! the!existing!studies!and!when!it!is,!it!refers!not!to!mere!awareness!of!the!air!pollution!problem!but!to!the!associated!health!effects!(Howel!et!al.,!2003).!!!The!last!source!of!public!awareness!of!the!air!pollution!issue,!and!in!this!case!also!the!least!important! one! currently,! is! information.! The! first! efforts! to! raise! public! awareness! of! the!environmental! problems! made! in! the! 1970s! were! precisely! focused! on! media! coverage.!Effectively,! since! then,! all! sorts! of! media! (TV! specials,! magazines,! telephone! helplines,!electronic!notice!boards,!statistical!digests,!media!bulletins…)!have,!at!some!point,!covered!the! air! pollution! problem.!However,! this! information! is! rarely! spontaneously! requested! and!frequently!disregarded!by!the!public,!partly!due!to!a!mismatch!between!personal!experience!(yet! again)! and! air! quality! data! provided.! In! a! survey! carried! out! in! Birmingham!aiming! to!quantify!sources!of!air!pollution!awareness,!only!3,4%!stated!media!as!a!source!of!awarenessf!that! same! survey! found! that! there! was! no! awareness! not! of! the! problem! itself! but! of! the!provided!information!about!it!(Bickerstaff!&!Walker,!2001).!!!Indeed,!the!gap!between!expert!and!lay!public!evaluation!of!the!air!pollution!issue!resides!on!the!dismissal!of!currently!available!information,!be!it!due!to!the!crucial!role!of!direct!experience!in!the!formation!of!awareness!or!to!the!fact!that!information!is!provided!in!the!wrong!format!

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and!contents.!There!seems!to!be!a!misconception!of!the!air!pollution!problem:!it!is!perceived!as!involuntary!and!ubiquitous,!as!a!fatality!of!which!citizens!cannot!be!held!responsible.!This!lack!of!knowledge!has!pushed!studies!to!focus!on!sources!of!information,!its!contents!and!its!efficiency.!!!

2.3.2! Information!about! the!air! pollution! crisis:! role,! sources,! current! contents! and!public!needs.!!

!The!role!of!the!information!provided!about!air!pollution!problems!is!said!to!fulfil!three!functions!by! (Bickerstaff,! 2004):! a! rightCtoCknow! function! (the! public! has! a! right! to! be! informed! of! a!potential! risk),! a! legitimation! function! (this! information! justifies! the! existence! of! the! risk!management!institutions,!their!actions!and!practices)!and!a!behavioural!change!function!(!it!is!meant! to! encourage! a! certain! behaviour! amongst! the! public).! Public! trust! on! information!sources!is!necessary!in!order!for!it!to!actually!accomplish!these!three!functions.!However,!little!credibility!is!placed!on!government!issued!information!related!to!air!pollution!which!leads!to!a!lack!of!effectiveness!of!the!communication!campaigns.!This!results!in!a!misconception!of!the!problem!that!has!been!proved!by!different!studies:!only!8%!of!the!environmental!damage!is!placed!on!machines!–!for!instance!cars!or!motorbikes!(Murch,!1971),!while!traffic!regulations!are!the!main!focus!of!current!policiesf!people!admit!their!lack!of!knowledge!on!the!air!pollution!issues,!making!it!“uncomfortable”!for!them!to!make!these!issues!responsible!for!specific!effects!(Wakefield! et! al.,! 2001)f! the! spatial! attachment! of! pollution! to! source! proximity! shows! a!disregard!of!environmental!dispersion!processes! (Bickerstaff!&!Walker,!2001)! .!Not!only! is!there!a!lack!of!knowledge!but!also!one!of!interest:!respondents!to!the!study!by!(Bickerstaff,!2004)!were!unaware!of!the!existence!of!the!available!air!quality!information!in!the!UK!and!even!if!its!existence!is!known,!there!seems!to!be!no!spontaneous!interest!for!it!(Bickerstaff!&!Walker,!2001).!!!It! is! important! to!mention! that! studies! have! noted! that!while! government! information! lacks!credibility,!there!are!other!sources!of!technical!or!scientific!information!about!air!quality!that!do!get!more!credit!from!the!public!(Beaumont,!Hamilton,!Machin,!Perks,!&!Williams,!1999).!These!are!mostly!environmental!nonCgovernmental!organisations!(ENGOs).!Indeed,!ENGOs!play!a!crucial! role! not! only! in! raising! public! awareness! in! the! lay! public,! but! also! in! influencing!legislators! and! policymakers! (Binder! &! Neumayer,! 2005).! In! order! to! gain! public! support,!ENGOs!coordinate!rallies!and!demonstrations!at!a!local!scale.!This!proximity!of!ENGOs!to!the!public!helps!embrace!a!message!that!is!otherwise!sustained!by!scientific!research!and!reports!directed!by!ENGOs! themselves.! Influencing! legislators!and!policymakers!needs!a!different!approach:!lobbying!(informal!and!formal),!promoting!boycotts,!taking!legal!action!or!executing!media!stunts!are!some!popular!ways!of!pressuring!politicians.!This!influence!is!backed!up!by!empirical!evidence!such!as!that!proposed!by!(Binder!&!Neumayer,!2005)!in!a!crossCcountry!study:! there! is! a! negative! statistically! relevant! relationship! between! ENGO! strength! and!concentrations!of!SO2,!smoke!and!heavy!particulates.!However,!it!is!important!to!nuance!that!ENGOs’!influence!is!limited!to!environmental! issues!that!affect!current!population!(Binder!&!Neumayer,!2005).!!!The!narrow!scope!of!governmental!communication!efforts!about!the!air!pollution!problem!has!spurred!studies!to!evaluate!the!current!contents!of!such!information!and!compare!them!with!the!public’s!needs.!According! to! (Beaumont!et!al.,! 1999f!Howel!et!al.,! 2003f!Murch,!1971f!Wakefield! et! al.,! 2001),! there! are! four! main! discrepancies! between! currently! available!information!and!the!public’s!needs.!Concerning! its! form,!the! language!used!is! too!technical!and!confusing.!Concerning!its!content,!there!is!a!demand!for!local!information!rather!than!the!actual! national! scale!usedf! the! information! should! consider! and!be! customised! for! interest!groupsf!the!information!should!clearly!state!air!pollution!health!effects!and!practical!ways!in!which! the! individual! can! act.! Indeed,! the! language! used! is! too! technical! and! sometimes!confusing!and!even!meaningless!to!the!lay!public.!For!instance,!some!air!quality!descriptors!and!terminology!(like!VOCs,!SO2,!NOX)!was!perceived!as!highly!technical!and!unknown!by!the!



public!(Bickerstaff,!2004).!There!is!also!a!strong!need!to!change!the!scale!used!to!provide!air!quality!information:!air!quality!information!provided!at!a!regional!or!national!scale!are!thought!to!have!little!relevance!at!local!scale!(Bickerstaff,!2004).!Adding!to!that,!national!coverage!of!the! air! pollution! issues! helps! build! the! image!of! the! issue! as! a! fatality.! Indeed,! even! local!newspapers! focus! on! the! national! environmental! problems! (Murch,! 1971).! Another!shortcoming!identified!in!available!information!is!the!fact!that!it!doesn’t!consider!the!existence!of! interest! groups,! such! as! asthmatics,! that! require! specific! recommendations.! Lastly,! air!quality!information!should!not!be!provided!on!its!own.!The!main!air!pollution!concern!among!the!public!is!its!health!effects!(Beaumont!et!al.,!1999f!Murch,!1971)!and!so,!information!should!be!directly!linked!to!health!effects!and!to!practical!ways!in!which!individuals!can!act!to!protect!themselves.!Indeed,!damage!to!the!environment!is!not!as!strong!a!motivator!as!personal!health!(Wakefield!et!al.,!2001).!Although!pollution’s!impacts!on!health!raise!the!most!concern!among!the!public,!there!is!a!big!lack!of!knowledge!on!the!health!effects!of!air!pollution.!This!will!be!considered!in!following!sections.!!!It! is!not!only! the!characteristics!of! information! that!have!been!analysed! in!studies!but!most!importantly!its!effectiveness.!Effectively,!many!studies!notice!that!very!few!times!is!information!backed!up!by!civic!action.!!

2.3.3! Moving!from!information!to!action!!According!to!(Wakefield!et!al.,!2001),!there!are!two!reactions!to!environmental!stressors:!some!people!engage!in!active!coping!or!“problemCfocussed!coping”!by!for!example!joining!a!local!citizen’s!groupf!others!stick!to!“emotionalCfocussed!coping”!by!simply!wishing!the!stressor!to!go! away.! Another! classification! of! actions! derived! from! environmental! concerns! would! be!actions!that!aim!to!mitigate!the!impacts!of!exposure!and!actions!that!aim!to!reduce!levels!of!exposure.!For!example,!mitigating!the!impacts!of!air!pollution!is!done!by!the!“reappraisal!of!lifestyle! options”! such! as! increased! cleaning,! staying! indoors! or! not! hanging! the! laundry!outside.!These!actions!do!not!support!social!change.!However,!actions!aiming!to!reduce!levels!of!exposure!themselves!could!be!what!is!referred!to!as!“personal!change”!which!are!individual!behavioural! changes! like! using! public! transit! or! recycling! and! ideally! “civic! action”! which!comprises!complaining!to!the!government!and!industries!or!signing!petitions.!Civic!action!can!be!done!individually!or!by!joining!groups.!!!However,! existing! studies! underline! the! predominance! of! emotionalCfocussed! coping! or!passive!strategies:!in!a!survey!carried!out!by!(Murch,!1971)!respondents!admitted!to!having!a!concern!about!air!pollution!and!some!even!believed! these!problems!could!be! reduced,!but!very!few!admit!to!having!tried!to!influence!governmental!or!corporation!policies’.!Likewise,!75%!of!respondents!of!a!survey!carried!out!by!(Wakefield!et!al.,!2001)!admitted!to!having!concerns!about!air!pollution!but!only!11%!had!made!attempts!to!contact!politicians!or!government!or!industry! representatives.! Effectively,! moving! from! awareness! to! action! is! not! so! straight!forward.! A! widely! accepted! explanation! is! the! fact! that! individuals! feel! powerless! when!confronted!to!an!elusive!problem!like!air!pollution.!This!is!referred!to!as!the!“sense!of!agency”!of!individuals!(Bickerstaff,!2004f!Wakefield!et!al.,!2001).!The!perception!of!air!pollution!as!a!ubiquitous! risk! is! closely! linked! to! the! fact! that! information! is! frequently! provided! at! larger!geographical!scales,!as!it!has!been!mentioned!before.!Another!explanation!is!that!individuals!lack! the!knowledge!on!what! to!do!and!who!and!how!to!contact! in!order! to!contribute! to!air!pollution! reduction! –! this! is! directly! related! to! the! shortCcomings! in! information! content!discussed!above!(Beaumont!et!al.,!1999f!Murch,!1971f!Wakefield!et!al.,!2001).!Lastly,!this!can!be!explained!by!the!fact!that!civic!action!is!associated!with!personal!sacrifice!and!compromise!(Wakefield!et!al.,!2001).!!!Civic!action!is!not!however!completely!absent.!Some!factors!have!been!revealed!to!encourage!it!and!the!presence!of!social!capital!within!the!community!and!the!attachment!to!it!are!the!most!important! ones! (Wakefield! et! al.,! 2001).! Social! capital! includes! all! associations! within! the!

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community! that! facilitate! its! coordination!and! coCoperation! like! social! clubs!or! even! league!teams.! These! social! networks!make! it! easier! to! engage! in! a! new! collective! action.! Place!attachment!leads!to!a!higher!willingness!to!improve!the!community!when!faced!with!a!serious!problem!instead!of!simply!leaving!it!(Wakefield!et!al.,!2001).!!!

2.3.4! The!rise!of!environmental!concern!and!social!media!!Today,!comments!on!social!media!are!the!equivalent!of!any!social!interaction!(Jiang,!Wang,!Tsou,!&!Fu,!2015).!If,!as!it!has!been!mentioned!above,!social!networks!facilitate!civic!action,!social! media! is! a! platform! that! provides! a! social! capital! as! big! as! the! number! of! users!registered.! Indeed,! showing! support! in! the! microblogging! service! Twitter! is! as! easy! as!retweeting&another!user’s!comment.!Furthermore,!by!being!able! to!mention!another!user! in!comments!–!this!means,!directing!the!comment!to!a!specific!user!that!is!then!notified!–,!and!bearing!in!mind!that!most!environmental!and!government!authorities!have!their!own!accounts!in!social!networks!like!Facebook!or!Twitter,!social!media!has!become!an!easy,!fast!and!direct!platform!of!complaints!and!social!debate.!!!This!is!so!much!so!that!many!studies!have!related!messages!issued!in!the!cyberspace!with!real! world! events! like! disease! outbreaks,! election! outcomes! and! natural! disasters! like!earthquakes!(Jiang!et!al.,!2015).!Studies!have!also!applied!social!media!to!estimate!air!quality!index!(AQI)!in!China,!by!using!messages!from!the!Chinese!microblogging!platform,!Sina!Weibo!(Jiang!et!al.,!2015f!Mei!et!al.,!2014f!Wang,!Paul,!&!Dredze,!2015).!Initial!studies!had!found!a!positive!relationship!between!the!volume!of!messages!containing!words!related!to!air!pollution!and!rises! in!AQI! levels,!bringing!to! light!a!social!awareness!of!air!pollution!events! in!China!(Wang!et!al.,!2015).!However,!posterior!studies!also!evaluate!the!content!of!the!message!and!relate! it! to! AQI! levels,! allowing! to! identify! the!most! popular! associations! with! air! pollution!among!the!lay!public!–!this!is,!their!main!concerns!–!!!and!the!different!reactions!to!air!pollution.!Also,!messages! issued! in! the!cyberspace!are! timestamped!and!many! times!geoClocalised,!classified!as!original!messages!or!retweeted!messages…!providing!more!information!than!just!that!of!air!pollution.!!!The!use!of!social!media!as!an!indicator!of!AQI!levels!responds!to!a!necessity!of!assessing!air!quality!by!other!means!than!the!traditional!fixed!monitoring!stations.!As!it!has!been!previously!mentioned,!these!stations!are!expensive!to!build!and!maintain!and,!in!opposition,!social!media!is!an!already!available!and!inexpensive!information!source!(Mei!et!al.,!2014).!Moreover,!the!resulting!models!allow! to!estimate!AQI! in!nearly! realCtime.! Indeed,!using!social!media!as!a!“social!sensor”!appears!as!a!direct!shortcut!to!data!previously!obtained!by!costly!C!in!time!and!money!C!!methods!like!interviews!and!questionnaires.!!!

2.3.5! Main!shortcomings!of!the!existing!studies!!!All! the!studies! found! in! the! literature!on! the!subject!of!social!awareness!of!air!pollution!are!based!on!postal!surveys!and!questionnaires!and!sometimes!posterior!inCdepth!interviews!with!some! of! the! survey’s! respondents.! Though! some! of! these! studies! do! show! quite! a! high!response!rate!–!84%!for!(Bickerstaff!&!Walker,!2001)!–,!it!is!evident!that!those!who!really!do!not!care!or!do!not!consider!the!air!pollution!problem!as!a!reality!will!not!answer!the!survey.!Indeed,! these!procedures! require!a!certain! level!of!engagement!of! the! individual!with! their!community!and!with!the!environment!itself,!besides!being!a!considerably!costly!practice.!Also,!it!is!very!possible!for!closedCended!questions!in!surveys!to!be!biased!and!therefore!to!push!the!respondent!to!answer! in!a!certain!way.!Moreover,!surveys!themselves!might!trigger!the!individual’s!concern!on!the!spot:!even!if!respondents!do!not!consider!air!pollution!an!issue!in!their!daily!lives,!when!asked!about!it!they!might!feel!guilty,!feel!embarrassed!or!even!shame,!to!answer!negatively.!!!



Based!on!the!uses!given!to!social!media!discussed!in!previous!sections,!it!seems!sensible!to!want!to!adopt!the!new!practice!of!analysing!the!content!of!messages!issued!in!the!cyberspace!to!help!evaluate!social!awareness!of!air!pollution!issues.!This!would!need!no!extra!effort!from!any!individual!and!it!would!truly!assess!the!actual!awareness,!since!personal!comments!are!surely!less!biased!than!answering!questions!on!a!survey!and!are!certainly!more!spontaneous!and!sincere!beliefs.!!!In!addition,!most!of!the!literature!relating!air!pollution!and!social!awareness!concentrates!on!estimating!social!awareness!of!air!pollution!but!does!not!deepen!into!the!possibility!of!using!public! awareness!as! “social! sensors”! of! air! pollution,! as! referred! to! in! (Jiang!et! al.,! 2015).!Literature!introducing!this!concept!is!quite!poorf!not!many!studies!have!been!carried!out!and!they! are! definitely! not! uniformly! distributed! in! a! geographical!wayf!most! studies! found! are!carried!out!in!Chinese!cities!(Jiang!et!al.,!2015f!Mei!et!al.,!2014f!Wang!et!al.,!2015).!It! is!definitely! interesting! to!explore! the!possibility!of!social!media!being!an!estimator!of!air!quality!due!to!economic!reasons!(it!could!avoid!building!more!monitoring!stations!and!could!obtain!predictions!for!places!without!stations)!and!practical!reasons!(related!to!time!efficiency!mostly).!Nevertheless,!by!using!only!social!media!data,!the!models!would!exclude!locations!that!are!remote!or!not!particularly!active!on!social!media.!Also,!it!must!be!taken!into!account!that!there!is!an!apparent!divergence!between!subjective!pollution!risk!and!risk!perception.!This!is!why!totally!disregarding!available!air!quality!measurements!would!not!be!the!best!option.!Ideally,!studies!should!integrate!heterogeneous!data!from!monitoring!stations,!social!media,!travel!patterns,!meteorological!data!and!possibly!traffic!flow,!in!order!to!build!a!thorough!and!reliable!model.!!!

2.4+ Social+awareness+of+health+impacts+of+air+pollution+studies+!The! lack! of! civic! action! related! to! air! quality! issues! is! intertwined! with! the! lack! of! social!awareness!of!the!broad!spectrum!of!pollution’s!effects!on!human!health.!Even!if!there!is!a!vast!body! of! work! of! epidemiological! studies! relating! specific! pollutants! to! very! serious! health!issues,!public!knowledge!seems!to!ignore!many!of!them.!This!however,!does!not!stop!health!effects! from!being! the!most! requested! information! related! to!air!pollution! (Beaumont!et!al.,!1999f!Wakefield! et! al.,! 2001).! Overall,! it! can! be! said! that! the! relationship! between! social!awareness!and!health!effects!of!air!pollution!is!full!of!contradictions.!Existing!studies!focus!on!two!main!contradictions:!first,!there!is!a!recognition!of!adverse!health!effects!of!air!pollution!issues!that!clash!with!the!denial!of!them!affecting!personal!healthf!second,!when!and!if!health!effects!are!acknowledged,!at!least!part!of!causation!is!systematically!attributed!to!something!else!than!air!pollution.!!!

2.4.1! Personal!invulnerability,!cognitive!dissonance!and!neighbourhood!halo!effect!!Health!effects!related!to!air!pollution!are!the!main!concern!of!the!public,!as!revealed!in!most!studies.!In!a!survey!carried!out!by!(Beaumont!et!al.,!1999),!of! the!80%!of!respondents!that!wished!to!have!regular!access!to!quality!information,!56%!wanted!it!due!to!health!concerns.!Indeed,!the!information!requested!regarding!air!pollution!is!demanded!to!be!linked!to!health!impacts! by! 88%! of! the! respondents! of! the! same! survey.! In! a! later! study! carried! out! by!!(Wakefield! et! al.,! 2001),! health! is! the! first! air! pollution! concern! (71%),! way! ahead! of! its!inconvenient!lifestyle!impacts!and!environmental!damage!it!causes.!Indeed,!health!impacts!of!air! pollution! are! accepted! but! only! on! a! societal! level,! hardly! ever! on! a! personal! one.!Respondents!of!many!studies!denied! the!harm!air!pollution!could!have!on! their!health,!but!were!keen!to!admit!the!harm!in!their!families’!health!or!simply!in!others’!(Bickerstaff!&!Walker,!2001f!Bickerstaff,!2004).!This!apparent!contradiction!can!be!explained!by!two!social!theories:!Billingsley’s!definition!of!personal!invulnerability!and!Festinger’s!cognitive!dissonance!theory.!Indeed,!personal!invulnerability!is!a!state!in!which!the!“individual!agrees!to!the!presence!of!a!danger!but!denies!it!will!happen!to!them”(Bickerstaff,!2004).!Alternatively,!it!could!be!said!that!individuals!agree!to!the!presence!of!a!danger!but!does!not!change!his!behaviour!because!of!

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it.!He!is!aware!of!the!health!effects!of!exposure,!and!exposes!himself!anyway!by!breathing!polluted!air!for!instance:!this!is!cognitive!dissonance!–an!inconsistency!between!actions!and!beliefs.!This!contradiction!happens!on!a!geographical! level!as!well:! individuals!consider!air!pollution! to! be! a! problem! on! a! national! scale! and! even! in! their! cities,! but! seldom! in! their!neighbourhoods.!This!is!referred!to!as!the!“neighbourhood!halo!effect”!(Bickerstaff!&!Walker,!2001f!Bickerstaff,!2004f!Howel!et!al.,!2003).!Once!again,!perception!plays!a!more!important!role!than!objective!facts.!!

2.4.2! Limits!in!the!acknowledgement!of!air!pollution!health!impacts!!Indeed,!only!a!few!number!of!individuals,!and!most!of!them!with!severe!physical!problems,!do!recognise!pollution!health!effects!in!themselves!(Bickerstaff!&!Walker,!2001).!However,!these!did!not!seem!to!have!a!profound!knowledge!and!above!all,!did!not!hold!air!pollution!as!the!one!and!only!responsible!of!the!health!effects.!!!Air!pollution!is!positively!linked!to!respiratory!issues!in!various!studies!(Bickerstaff!&!Walker,!2001)! such! as! allergies,! asthma! and! bronchitis! but! other! issues! such! as! lung! cancer,!cardiovascular!disease!or!circulatory!problems!which!are! linked! to!air!pollution!by!scientific!evidence!seem!to!be! ignored!by! the! lay!public! (Howel!et!al.,!2003).!This! is!quite!alarming,!since!the!ignorance!seems!to!exceed!lay!public:!workers!in!the!sanitary!field,!such!as!chemists!or!hospital!administrators!are!quite!unfamiliar!with!the!not!so!obvious!effects!of!air!pollution!–!that!is!those!that!are!not!merely!respiratory!(Bickerstaff!&!Walker,!2001).!!Indeed,!discomforts!like!“chestiness,!asthma,!sore!throats,!headaches,!fatigue!and!irritability”!are!more!often!than!not!related!to!other!causes.!!!This!ignorance!is!also!linked!to!a!social!theory:!by!moving!causation!of!health!impacts!related!to!air!pollution!somewhere!else,!particularly!in!uncontrollable!factors,!there!is!no!way!of!holding!individuals!responsible!for!a!worldwide!problem!(Bickerstaff!&!Walker,!2001).!!Causes!of!health!impacts!are!sometimes!placed!upon!personal!“bad!habits”!like!smoking,!making!the!individual!responsible!for!himself!and!not!having!to!carry!the!weight!of!harming!others!(Wakefield!et!al.,!2001).! More! often,! causes! are! attributed! to! natural! environmental! events! like! pollen,!temperature!or!weather!conditions,!or!to!social!events!like!poverty.!Other!times,!socioCcultural!reasons!are!given:!it!is!a!consequence!of!an!overCprotective!and!weak!society!(Bickerstaff!&!Walker,!2001).!!!

2.4.3! Main!shortcomings!of!the!existing!studies!!!Once!more,!most!of!the!existing!studies!searching!the!social!awareness!of!health!impacts!of!air!pollution!are!based!on!surveys!and!questionnaires.!And!again,!these!methods!present!the!problem!of!biased!questions!and!response!rates.!!!Furthermore,!unlike!studies!about!social!awareness!of!air!pollution!itself,!these!studies!seem!to!focus!on!measuring!the!knowledge!of!the!lay!public!about!air!pollution!health!effects!but!do!not! propose! ways! of! improving! awareness.! They! do! not! investigate! public! needs! and!preferences!about!information!related!to!health!effects!of!air!pollution.!!!In!a!similar!fashion,!analysing!the!content!of!messages!in!social!media!might!help!evaluate!social!awareness!not!only!of!air!pollution!but!also!of!its!health!effects,!avoiding!biased!answers!and!ensuring!individual’s!honesty,!if!not!completely,!more!than!questionnaires!and!surveys.!!!Also,!studies!seem!to!be!a!little!outdated.!The!most!recent!studies!found!on!the!open!literature!date!from!2004.!Since!then,!many!behaviours!surely!have!changed!related!to!environmental!causes!but!also!health!related!causesf!it!would!be!interesting!to!say!the!least!to!find!today’s!views!and! knowledge!on! the! subject! and! it! could! help! evaluate! the!efficiency!of! the! latest!adopted!measures.!!



!2.5+ Air+quality,+social+awareness+and+health+effects+related+studies++

!As!it!has!been!reviewed!in!previous!sections,!there!are!many!epidemiological!studies!that!link!pollutant’s!concentration!to!hospital!admissions!and!a!few!lesser!that!study!social!awareness!of!air!pollution!itself!and!of!its!health!effects.!The!latest!trend!related!to!air!pollution!studies!is!the! assessment! of! air! quality! through! different! sources! to! the! traditional! fixed! monitoring!stations.!These!new!sources!of!information!include!mobile!laboratories!that!incorporate!microCsensors!as!measuring!instruments,!location!of!individuals!through!GPS!or!mobile!phone!data,!estimation!of!AQI! through!volume!of!messages! related! to!air! pollution! in! social!media!and!estimation!of! views!and! concerns!on!air! pollution! through! the! contents!of! such!messages.!These!alternative!methods!of!assessment!allow!for!a!better!personal!exposure!assessment!and!hence!a!possibly!better!but!unexplored!estimation!of!health!effects!on!the!individual.!!Indeed,! all! three! aspects! –! air! quality,! social! awareness! and! health! effectsC! seem! to! be!intertwined! and! are! definitely! not! independent! matters.! One! of! the! core! incentives! for!measuring! air! pollution! is! its! impact! on! public! health.! This! means! that! even! if! AQPs! are!generated! to!comply!with! legislation,! their!origin! relies!on!an!environmental!but!also!public!health!concern!(EU!Parliament!and!Council,!2008).!Effectively,!air!pollution!assessment!is!also!used!to!raise!lay!public’s!awareness!of!its!health!effects.!Measuring!the!social!awareness!of!air!pollution!itself!and!of!its!health!effects!is!nothing!more!but!a!way!of!measuring!the!efficiency!of!the!government’s!efforts!to!deal!with!the!air!pollution!crisis.!This!goes!to!say!that!though!studies!may!only!relate!one!or!two!of!the!three!stated!aspects!of!the!air!pollution!problem!as!a!whole,!they!are!also!implicitly!helping!progression!on!the!other!fields!of!research.!!!The!realisation!of!the!undeniable!relationship!between!air!pollution!exposure!and!human!health!is!one!of! the!reasons!of!starting! the!Kavli!Human!Project! (KHP)!(Ausiello!&!Lipnick,!2015).!This!project!aims!to!fully!exploit!the!current!advances!in!human!genetics!by!integrating!it! in!medical!practices.!In!order!for!genetic!information!to!effectively!help!make!better!diagnosis,!it!must! be! completed! with! phenotypic! information! –! the! environment! and! behaviour! of! an!individual.!It!is!in!the!assessment!of!the!phenotype!that!pollution!exposure!–!notably!inhalation!and!intake!of!toxins,!is!relevant.!Although!exposure!assessment!is!mentioned!in!the!KHP,!a!precise!way!of!obtaining!of!information!is!not!given.!Furthermore,!one!of!the!goals!of!this!study!is!to!transform!social!awareness!of!the!individual’s!human!health!and!wellness.!However,!this!project!sets!a!good!example!of!merging!of!heterogeneous!data!and!of!exploiting!the!newest!technological!tools!available!such!as!sensors!and!increasing!computing!capabilities.!!!Although!the!KHP!seems!to!explore!air!quality,!public!health!and!social!awareness!as!part!of!a! wider! project,! when! implementation! of! the! project! is! described,! pollution! exposure! is!suddenly!missing.!Furthermore,!social!awareness!is!not!linked!to!air!pollution!but!to!individual!health!and!wellness!and!is!not!aimed!to!be!measured!but!to!be!a!consequence!of!the!study.!!!Indeed,! even! if! air! quality,! social! awareness! and! its! public! health! impact! go! hand! in! hand!implicitly,!there!are!no!studies!in!the!current!open!literature!that!explicitly!use!heterogeneous!data!from!monitoring!stations,!hospital!admissions!and!public!awareness!about!both!of!these.!!

2.6+ Highlights+of+the+literature++!Monitoring!air!pollution!is!a!legal!obligation!in!many!countries,!driven!by!the!protection!of!the!environment! but! also! of! public! health.! Most! official! studies! carried! out! inside! the! legal!framework!use!data!measured!in!fixed!monitoring!stations.!However,!exposure!assessment!derived! from! such! studies! has! a! few! noticeable! deficiencies.! Firstly,! assessing! personal!exposure!using!exclusively!measurements!from!fixed!monitoring!stations!and!censorial!data!implies!that!people!stay!at!home!all!day!long.!Secondly,!fixed!stations!only!provide!data!from!their!specific!location!and!since!they!are!sparsely!located,!they!leave!many!areas!uncovered.!

State!of!the!Art!!


While! the! use! of!models! is! legally! encouraged! to! try! to! overcome! this! obstacle,! given! the!complex!nature!of! the!environmental!processes!related! to!air!pollution! these,! too!are! faced!with! inherent! uncertainties.! Aiming! to!make! a! better! personal! exposure! assessment! to! air!pollution,!researches!are!using!new!sources!of!air!quality!information!like!mobile!monitoring!stations! equipped! with! the! latest! technology! in! microCsensing! instruments,! location! of!individuals!through!GPS!or!mobile!phone!data,!and!most!recently,!through!social!media!related!comments.!This!new!trend!is!not!yet!an!established!practice,!partly!due!to!the!lack!of!legislation!about!its!usability.!!!A!better!personal!exposure!assessment!would!largely!benefit!epidemiological!studies.!In!the!literature,!epidemiological!studies!are!the!most!popular!air!quality!related!studies.!They!link!air!pollution!to!mortality!and!morbidity!occasioned!by!specific!respiratory!issues,!cardiovascular!issues!and!circulatory!issues.!Moreover,!they!establish!the!elderly,!pregnant!women,!children!under!5!and!asthmatics!as!populations!at!riskf!they!are!the!most!susceptible!to!air!pollution’s!health!impacts.!!!However,!legislation!can!only!do!so!much!in!the!preservation!of!environment!and!public!healthf!it!must!be!backed!up!by!individual!awareness!and!civic!(re)action.!!Studies!have!found!a!gap!between!objective!risk!estimated!by!experts!and!subjective,!perceived!risk!by!the!lay!public.!This!discrepancy!is!also!found!in!the!awareness!of!health!impacts!of!air!pollution:!while!the!scientific!community!has!deeply!researched!the!issue,!general!knowledge!about!this!is!very!low.!The!only!known!health! impacts,!when! they!are!known,!by! the! lay!public!are! the!most!obvious! ones:! respiratory! issues.! Cardiovascular! and! circulatory! impacts! are! widely!disregarded.!These! inconsistencies!suggest! that!measures!directed!by!authorities!are!quite!inefficient.!!!However,! the! latest! studies!advocate!a! turn!of! the! tide! in!what! concerns!awareness!of! air!pollution.!With! the! ubiquity! of! social!media! in! individual’s! daily! lives,! online! networks! have!proven!themselves!to!be!a!powerful!social!tool,!hosting!social!debates!and!complaints!in!many!fields.! Information!extracted! from!social!media!has!been!used! in!pilot!studies! related! to!air!pollution.!Indeed,!variations!of!the!volume!of!content!created!on!social!media!related!to!the!air!pollution! subject! has! been! found! to! correspond! to! variations! of! the! actual! pollutants’!concentration!levels!in!urban!air.!!!Including!data!from!social!media!in!an!air!pollution!related!study!seems!to!alleviate!the!main!shortcomings!of!the!existing!studies!related!to!awareness!of!air!pollution!and!of!its!impact!on!public!health.!Also,!it!is!considered!within!the!alternative!sources!of!air!quality!monitoring!along!with!mobile!stations!and!individual! travel!patterns.!Nevertheless,!up!to!this!date,!no!studies!have!been!found!on!the!open! literature!explicitly! feeding!off!of!heterogeneous!data!coming!from!fixed!monitoring!stations,!hospital!admissions!and!social!media.!!!!



3! OBJECTIVES!!It!could!be!said!that!studies!in!the!literature!provide!empirical!evidence!to!support!the!following!statement:!!!

(i)! The!greater!the!air!pollution!levels,!the!greater!the!health!impacts.!!!However,! the! two! following! statements! have! to! deal! with! a! social! component,! and! not! all!studies!in!the!literature!support!them:!!!

(ii)! The!greater!the!air!pollution!levels,!the!greater!its!social!awareness.!!(iii)! The!greater!the!health!impacts!of!air!pollution,!the!greater!its!social!awareness.!!

!Indeed,!the!existence!of!psychological!and!socioCcultural!factors!like!personal!invulnerability,!neighbourhood!halo!effect!or!cognitive!dissonance!complicate!the!declaration!of!statements!(ii)! and! (iii).! Nevertheless,! evidence! supporting! (ii)! and! (iii)! would! reveal! the! efficacy! of!communication! campaigns! concerning! the! air! pollution! problem.! This! means! that,! ideally,!evidence!should!support!them!and!checking!them!is!a!way!of!measuring!efficacy!of!the!current!situation.!Furthermore,!like!it!has!been!stated!earlier,!studies!concerning!social!awareness!are!not!extremely! recent,!and! in! the!past! two!years!or!so,!a!new!ecological!and!environmental!concern!has!apparently!aroused.!!!!Everything!considered,!the!first!objective!of!this!monography!is!to!add!empirical!evidence!to!support! statements! (i),! (ii)! and! (iii).!Effectively,! the! recent!polemic!created!around!pollution!crisis! suggest! that! if! statements! (ii)! and! (iii)! haven’t! been! strongly! supported! by! earlier!evidence,!there!is!no!better!time!to!shine!a!light!on!them.!!!The!second!objective!of!this!monography!is!to!try!to!establish!a!predictive!model!of!the!health!impacts!of!air!pollution!through!heterogeneous!data!from!hospital!admissions!themselves,!air!quality!measurements,!meteorological!data,!holiday!data!and!social!awareness!data.!If!this!is!achieved!successfully,!it!will!result!in!a!very!powerful!tool!allowing!to!access!nearly!realCtime!information! that! will! allow,! for! instance,! better! allocation! of! health! resources! and! better!informed!decision!making!in!the!public!health!department.!The!aim!of!this!study!is!to!predict!the!total!number!of!hospital!admissions!with!a!time!lag!as!wide!as!possible.!!!!!!!!!!!!!!!!!!!!!

Objectives!


!!!!!!!!!!!!



!

4! METHODOLOGY!!New! trends! in!studies! related! to!air!pollution!make!use!of!a!new!set!of! tools! that!allow!an!assessment!of!air!quality!that!is!more!precise!in!calculating!personal!exposure!assessment,!providing!nearly!realCtime!information!as!well.!Also,!no!studies!were!found!in!the!open!literature!explicitly!using!heterogeneous!data!from!air!quality,!public!health!and!social!awareness!and!merging!that!data!into!a!single!study.!!!Nevertheless,! taking! into!account! the! limitations!discussed! for! the!actually!existing!studies,!this!field!could!benefit!from!these!new!study!tools.!Indeed,!based!on!current!scientific!findings,!this!monography!aims!to!accomplish!its!objective!of!explicitly!studying!the!existing!relationship!between!air!quality,!public!health! impacts!and!social!awareness!of!both!events! through!the!use!of!heterogeneous!data!and!data!mining!techniques.!!!

4.1+ Study+area+!As!it!was!suggested!earlier,!this!monography!will!study!the!mentioned!statements!in!the!urban!region!of!Madrid.!At!the!end!of!2015,!the!Autonomous!Community!of!Madrid!had!a!population!of!6!436!996!(INE,!2015),!while!the!municipality!of!Madrid,!which!also!corresponds!with!the!city!of!Madrid!had!a!population!of!3!165!883,!of!which!1!473!397!(46,5%)!are!men!and!1!692!486!(53,4%)!are!women!(Ayuntamiento!de!madrid,!2016).The!municipality!or!city!of!Madrid!takes!up!604,3669!km2!of!land!and!a!population!density!of!5!238!inhabitants!per!km2.!811!769!(25,6%)!inhabitants!of!Madrid!are!over!60!years!oldf!146!691!(4,6%)!are!under!5.!!!The! city! of! Madrid! is! indeed! a! high! population! density! area! exposed! to! high! levels! of! air!pollution.!For!instance,!it!is!interesting!to!contemplate!the!presence!of!mobile!sources!of!air!pollution,!consisting!mainly!of!the!traffic!flow.!By!2014!the!city!registered!a!vehicle!float!of!1!695!213!units.!Since!then,!62!762!new!vehicles!were!registered!in!2015!and!14!655!have!been!registered!so!far!in!2016.!Furthermore,!there!are!also!stationary!sources!of!air!pollution!which!are! present! in! Madrid! like! power! or! heating! generation! stations.! Indirectly,! this! can! be!measured!by!the!electricity!and!gas!consumption:!in!2015!12,629!x!109!kW/h!were!charged!in!the! city! for! electricity! consumption! and! in! 2014,! 8,193! x! 109! kW/h! were! charged! for! gas!consumption,! of!which!22,! 5%!was!used! for! industrial! purposes! (Ayuntamiento!de!madrid,!2016).!!!!

4.2+ Data+collection++!As! it! has! been! stated! before,! this!monography!will! use! heterogeneous! data! related! to! air!pollution,!its!public!health!impact!and!its!social!awareness.!This!section!aims!to!provide!the!operational!definitions!of!these!three!concepts.!!!

4.2.1! Air!pollution!!

•! Pollutants’!concentration!!!Air!pollution!in!the!city!of!Madrid!will!be!measured!through!concentration!of!pollutants!provided!by!the!network!of!fixed!monitoring!stations!of!the!city!of!Madrid.!This!network!consists!of!24!remote!stations!which!can!serve!different!purposes:!some!stations!are!referred!to!as!“urban!background!stations”!and!they!aim!to!represent!the!exposure!of!urban!population!as!a!wholef!some!stations!are!called!“traffic!stations”!which!aim!to!assess!exposure!close!to!sources!of!pollution!in!a!street!or!roadf!a!third!group!are!known!as!“suburban!stations”,! located!further!

Methodology!


away!from!the!city,!were!ozone!levels!are!highest.!Image!1!shows!the!spatial!distribution!of!the!24!fixed!monitoring!stations!in!the!city!(Ayuntamiento!de!Madrid,!n.d.).!!!Urban+Background+Stations+ Traffic+Stations+ Suburban+Stations+Plaza!del!Carmen!! Plaza!de!España! Casa!de!Campo!Vallecas! Barrio!del!Pilar! El!Pardo!Arturo!Soria! Escuelas!Aguirre! Juan!Carlos!I!!Villaverde! Cuatro!Caminos! !Farolillo! Ramón!y!Cajal! !Barajas! Moratalaz! !Méndez!Álvaro! Castellana! !Retiro! Plaza!de!Castilla! !Ensanche!de!Vallecas! Plaza!Fernández!Ladreda! !Embajada! ! !Sanchinarro! ! !Tres!Olivos! ! !Table&8&Classification&of&the&monitoring&stations&according&to&type&of&station.&&

These!stations!can!measure!up!to!14!different!pollutants!through!different!instruments.!Some!pollutants!use!photometric!methods!of!measurement:!!indeed,!SO2!is!measured!by!measuring!the!fluorescence!of!SO2!molecules!after!their!exposure!to!ultraviolet!(UV)!lightf!CO!is!measured!by!its!absorption!of!infrared!lightf!O3!is!also!measured!by!absorption,!but!of!UV!light.!!!NO!and!NOX!assessment!uses!chemiluminescence:!NO!reacts!with!O3,!liberating!energy!that!can!be!measured!in!the!form!of!protons.!NO2!must!be!converted!to!NO!before!reacting!with!O3,!obtaining!a!final!measure!of!NOX!and!therefore!and!indirect!measure!of!NO2.!!PM! is! firstly! separated! by! size! into! PM10! and! PM2,5f! then,! a! microCscale! assesses! the!concentration!of!the!two!pollutants.!Toluene!(TOL),!benzene!(BEN),!ethylbenzene!(EBE),!and!xylenes!C!metaexylene!(MXY),!paraxylene!(PXY)!and!ortoxylene!(OXY)!C,!are!measured!by!gaseous!chromatography.!CH4!is!measured!by!a!detector!of!ionisation!of!a!hydrogen!flame.!!However,!not!all!stations!measure!all!pollutants.!Table!9!shows!the!measurements!of!each!station.!The!concentration!of!pollutants!is!measured!hourly!and!the!data!is!sent!with!the!same!frequency!by!telephone!lines!and!VPN!virtual!networks.!!The!hourly!measurements!of!concentration!of!pollutants! is!made!available! to! the! lay!public!through! Madrid’s! city! council! web! page.! Data! is! available! for! download! in! hourly! or! daily!concentrations! since!2001.!For! the!purpose!of! this! study!not! all! pollutants!measured!were!useful.!Indeed,!selected!pollutants!coincide!with!the!available!common!pollutants:!SO2,!CO,!NO,!NO2,!PM10,!PM2,5!and!O3.!Data!was!downloaded!for!these!pollutants!in!2014!and!2015.!!While!realCtime!data!is!published!online!as!it!is!received!from!the!stations,!daily!and!monthly!validations!are!carried!out!when!measures!are!incorporated!to!the!database!of!the!city!council.!However,! there!were!many! times!when!data!was!missing! for! several!hours,! in!which!case!concentrations!were!marked!as!null.!!!!



!Image&1&Map&of&the&distribution&of&the&network&of&monitoring&stations&of&air&quality&&in&the&city&of&Madrid..&&

!&

&+

STATION+POLLUTANTS+ METEOROLOGICAL+DATA+

SO2+ CO+ NO+ PM2,5+ PM10+ NO2+ O3+ BEN+ UVA+ SPD+ DIR+ T+ RH+ P+ SR+ R+PzaCarmen! X! X! X! ! ! X! X! ! ! ! ! ! ! ! ! !Vallecas! X! ! X! ! X! X! ! ! ! ! ! ! ! ! ! X!ArturoSoria! ! X! X! ! ! X! X! ! ! ! ! ! ! ! ! X!Villaverde! X! ! X! ! ! X! X! ! ! ! ! ! ! ! ! !Farolillo! X! X! X! X! X! X! X! X! ! ! ! X! ! ! ! X!Barajas! ! ! X! ! ! X! X! ! ! ! ! ! ! ! ! !

MendezAlvaro! ! ! X! X! X! X! ! ! ! ! ! ! ! ! ! !Retiro! ! ! X! ! ! X! X! ! ! ! ! ! ! ! ! !

E.Vallecas! ! ! X! ! ! X! X! ! ! X! X! X! ! ! X! X!Embajada! ! ! X! ! X! X! ! X! ! ! ! ! ! ! ! !Sanchinarro! X! X! X! ! X! X! ! ! ! ! ! X! ! ! ! !TresOlivos! ! ! X! ! X! X! X! ! ! ! ! ! ! X! ! X!

Methodology!


Pza!España! X! X! X! ! ! X! ! ! ! X! X! X! X! ! ! X!Barrio!Pilar! ! X! X! ! ! X! X! ! ! ! ! ! ! ! ! X!E.Aguirre! X! X! X! X! X! X! X! X! ! ! ! ! ! ! ! !

CuatroCaminos! X! ! X! X! X! X! ! X! ! ! ! X! ! ! ! X!RamónCajal! ! ! X! ! ! X! ! X! ! ! ! ! ! ! ! X!Moratalaz! X! X! X! ! X! X! ! ! ! ! ! ! ! ! ! X!Castellana! ! ! X! X! X! X! ! ! ! ! ! ! ! ! ! !Pza!Castilla! ! ! X! X! X! X! ! ! ! ! ! X! ! ! ! !

PzaFdezLadreda! ! X! X! ! ! X! X! ! ! X! X! X! X! ! ! X!CasaCampo! X! X! X! X! X! X! X! X! X! X! X! X! X! X! X! X!El!Pardo! ! ! X! ! ! X! X! ! ! ! ! ! ! ! ! !

Juan!Carlos!I! ! ! X! ! ! X! X! ! X! X! X! X! X! X! X! X!RETIRO! AEMET!station:!only!meteorological!

data!! X! X! X! X! X! ! X!

CIU! X! ! ! ! ! ! X! !Table&9&Pollutants&and&meteorological&variables&measured&in&each&station.&&

!•! Meteorological!data!

!However,!since!dispersion!is!an!important!environmental!process!in!the!air!pollution!problem,!meteorological! data! must! also! be! taken! into! account! for! the! purposes! of! this! study.! The!meteorological!data!obtained!comes!from!two!sources.!Firstly,! the! fixed!monitoring!stations!measuring! pollutants’! concentrations! also! measure! some! meteorological! variables.!Nevertheless,!these!stations!are!not!specifically!designed!to!obtain!meteorological!data!and!therefore!instruments!are!not!properly!protected!against!meteorological!conditions.!Hence,!as!advised!by!the!System!of!Environmental!Information!of!the!Municipality!of!Madrid,!data!was!also!obtained!from!two!stations!owned!by!the!State!Agency!of!Meteorology!of!Spain!(AEMET),!which! are! specifically! built! for! taking!meteorological!measures.! ! The! location! of! these! two!additional!stations!is!shown!in!Image!2.!!!Meteorological!variables!of!interest!selected!were,!on!an!hourly!basis!for!2014!and!2015:!UVA!radiation! (UVA),!wind!speed!(SPD),!wind!direction! (DIR),! temperature! (T),! relative!humidity!(RH),! pressure! (P),! solar! radiation! (SR)!and! rainfall! (R).!Again,! not! all! stations!are!able! to!measure!all!these!variables,!as!it!is!shown!once!more!in!Table!9.!Stations!RETIRO!and!CIU!correspond!to!the!AEMET!stations.!!!

!Image&2&Location&of&the&AEMET&meteorological&stations&



!4.2.2! Public!health!data!

!Public!health!in!the!city!of!Madrid!will!be!measured!in!this!study!through!hospital!admissions!in! public! hospitals! related! to! the! air! pollution! problem! collected! in! the! Joint! Standardized!minimum!basic!dataset!(CMBD!in!Spain).!The!city!of!Madrid!counts!on!15!public!hospitals,!distributed!as!shown!inside!the!green!figure!in!Image!3.!!!The!CMBD! is! the! result! of! a!European! initiativef! it! keeps! track!of! hospital! admissions!and!ambulatory!surgery.!Its!elaboration!is!compulsory!for!all!public!and!private!hospitals!in!the!city!of!Madrid.!!!A!hospital!admission!refers!to!the!occupation!of!a!hospital!bedding,!while!ambulatory!surgery!is! registered! with! or! without! an! overnight! stay.! Therefore,! hospital! transactions! like!emergencies,!observation!in!medical!practices!or!patients!treated!at!home!are!excluded!from!the!CMDB.!!!The! data! to! be! included! in! the!CMBD,! as! requested! by! the!EU!must! include! centre! code!identification,!clinical!history!number!of!the!patient,!date!of!birth,!sex,!residence,!financing,!date!of! admission,! circumstances! of! admission,! diagnosis,! surgeries,! other! procedures,! date! of!intervention,!date!of!release,!circumstances!of!release,!service!of!release!and!transfer!centre.!The!data!collected!on!each!hospital!must!be!sent!on!a!quarterly!basis!to!the!Dirección&General&de& Sanidad,! the! public! health! administrative! institution! in! the! Autonomous! Community! of!Madrid.!!!The! diagnosis! information! collected! in! the!CMBD! is! codified! according! to! the! International!Classification!of!Diseases!(ICD).!For!the!purposes!of!this!study,!only!the!diagnosis!related!to!air!pollution!were!collected.!Indeed,!the!diagnosis!chosen,!shown!in!Table!10,!correspond!to!diagnosis!that!the!literature!has!linked!to!air!pollution.!!Due!to!data!protection!not!all!instances!of!data!actually!collected!in!the!CMBD!were!made!available!for!this!study.!However,!CMBD!data! provided! by! the! General! Direction! of! Coordination! of! Sanitary! Assistance! of! the!Community!of!Madrid!comprises!name!of!hospital,!sex!and!age!of!patient,!date!of!admission!and!release,!diagnosis,!type!of!admission!and!type!of!release!for!all!hospital!admissions!and!ambulatory!surgeries!during!2014!and!2015.!!!

ICDa9+Code+ Diagnosis+460!to!519! Diseases!of!the!Respiratory!System!

410!to!417,!420!to!438!and!440!to!444!

Cardiovascular!Diseases:!!Ischaemic! heart! disease,! diseases! of! pulmonary! circulation,!other! forms! of! heart! disease,! cerebrovascular! disease! and!diseases!of!arteries,!arterioles!and!capillaries!

493! Asthma!490C496! Chronic!Obstructive!Pulmonary!Disease!480C488! Pneumonia!and!Influenza!428! Heart!Failure!

410!to!414! Ischaemic!heart!Disease!430!to!438! Cerebrovascular!Disease!390C459! Circulatory!!

! Mortality!! Total!Admissions!

Table&10&Codification&of&Diagnosis&according&to&the&ICD_9&&selected&for&this&study.&&

!

Methodology!


!Image&3&Public&Hospitals&in&the&Community&of&Madrid.&Circled&in&green,&hospitals&in&the&city&of&Madrid.&&

As!it!has!been!suggested!above,!data!used!in!this!study!excludes!visits!made!to!emergency!rooms!or!to!medical!practices!that!do!not!lead!to!hospital!admissions,!as!well!as!any!admission!made!on!a!private!hospital.!!!

4.2.3! Social!awareness!data!!!Social!awareness!of!air!pollution!and!health! impacts!will!be!measured!in!this!study!through!comments!published!in!the!microblogging!social!network!Twitter.!This!social!network!claims!to!have!310!million!monthly!active!users,!which!places!it!as!the!third!most!popular!social!network,!after! Facebook! (with! 1! 100!million!monthly! active! users)! and!YouTube! (with! 1! 000!million!monthly!active!users).!However,!Facebook!and!YouTube!are!more!inclined!to!visual!content!whereas!Twitter!is!definitely!oriented!to!textual!content.!Therefore,!Twitter!appears!to!be!the!most! popular! textual! social! network!worldwide,!making! it! the! best! operational! definition! of!social!awareness!in!social!media.!!!In!2014,!Twitter!announced! they!would!be! indexing!all!public! tweets!since!2006.!However,!Twitter’s!Search!API!only!provides!tweets!that!are!a!few!days!old!(6!to!8).!Considering!that!the!rest!of!the!data!collected!for!this!study!is!from!2014!and!2015,!using!Twitter’s!Search!API!is!not! an! adequate! option.!However,! Twitter’s! Advanced!Search! site! does! provide! all! tweets!published! based! on! several! search! parameters! like! keyword,! location! or! date.! In! order! to!collect!Twitter!data!from!the!Advanced!Search!engine!without!doing!so!manually,!a!scraper!has!to!be!put!into!place.!!!Web!scraping!copies!content!from!other!websites!by!creating!a!software!that!simulates!manual!navigation.!Indeed,!the!scraper!code!is!built!after!observing!the!URLs!produced!when!doing!a!manual! search.! Hence,! the! scraper! allows! to! build! an! adequate! URL! based! on! the! input!parameters!of!the!search,!but!also!to!retrieve!and!manage!the!results!of!the!search!by!creating!additional!functions.!!!



When!searching!for!tweets!in!the!Twitter!Advanced!Search!Engine,!not!all!results!are!displayed!at!once.!Indeed,!one!must!scroll!down!in!order!to!load!more!results.!Each!time!one!arrives!to!the!bottom!of!the!displayed!results,!Twitter!makes!a!call!to!a!new!URL.!This!process,!which!is!automatic!when!manually!searching!for!tweets,!must!be!explicitly!built!on!the!scraper.!Indeed,!as!it!will!be!explained!later,!the!URL!created!by!the!scraper!will!constantly!be!updated,!until!there! are! no! more! tweets! to! show! or! the! maximum! number! of! tweets! to! be! obtained! is!achieved.!!!Also,!each!URL,!which!corresponds!to!a!certain!number!of!tweets!displayed!or!a!query,!is!also!a!JavaScript!Object!Notation!(JSON)!response.!This!JSON!response!contains!many!properties!like!the!Boolean!property!“has_more_items”!which!indicates!if!there!are!more!results!after!this!query!or!the!items_html!property.!This!property!is!an!HTML!block!containing!a!great!deal!of!information!of! the!tweets!generated! in! this!query.!Obtaining!the! information!collected! in! the!items_html! property! requires! organisation! and! building! of! a! data! structure! –! this! is! called!parsing.!!!For!the!purpose!of!this!study,!Professor!Joaquín!Ordieres!developed!a!scraper!using!Python!programming!language,!based!on!a!contribution!from!Tom!Dickenson.!Some!of!the!variables!used!are!shown!in!Table!12.!!!The! development! of! the! scraper! needs! at! first! the! definition! of! its! own! classes! of! objects:!TwitterSearch!and!an!inherited!class,!TwitterSearchImpl.!!!Any! TwitterSearch! class! object! will! need! the! definition! of! two! attributes:! rate_delay! and!error_delay.!While!rate_delay!refers!to!the!time!between!the!creation!of!new!URLs!(to!simulate!the!scrolling!and!automatic!loading!of!a!new!page!of!results)!and!error_delay!refers!to!the!time!between!an!error!and!the!next!URL!call.!Furthermore,!inside!the!TwitterSearch!class,!many!functions!are!defined,!as!shown!in!Table!11.!!Function+Name+ Input+Arguments+ Return+construct_url+ query!

max_position!url!!

Encodes&an&URL&like&the&one&created&by&Twitter&when&using&the&Advanced&Search&Engine&

based&on&the&made&query.&

execute_search+ url! response!Executes&a&Twitter&Search&based&on&the&previously&url&string&constructed.&

parse_tweets+ response! tweets!Turns&the&HTML&items_html&block&of& tweets&found&by&execute_search& into&a&JSON&list&of&

tweets.&Each&tweet&JSON&object&has&many&parameters:& twitter&handle,& text,&user& id,&user&

screen& name,& date& of& creation,& number& of& retweets,& number& of& favourites.& Then,& this& is&

appended&into&a&list&of&tweets.&

save_tweets+ tweets! True! or! False! depending! on!whether!the!number!of!saved!tweets!exceeds!the!maximum!

Writes&each&instance&of&the&JSON&input&list&into&an&output&file.&

search+ query!! !Calls&to&the&construct_url&function&in&order&to&generate&a&valid&search&URL&stored&in&the&url&

variable.&&

Passes&the&variable&url&as&an&argument&for&the&execute_search&function.&Saves&the&JSON&

object&created&in&the&variable&response.&&

Creates&a&while%loop&that&requires&the&response&variable,&the&items_html&parameter&in&the&response&variable&and&the&continue_search&variable&to&be&True.&Inside&the&loop:&&

Passes& the& items_html& inside& the& response& JSON&object& as& an& argument& for& the&

parse_tweets&function.&Saves&the&JSON&list&generated&in&the&variable&tweets.&&

Methodology!


Creates&different&if&loops&that&aim&to&identify&if&there&are&effectively&any&tweets&and&to&

identify&the&first&tweet&saved&in&the&list,&which&is&assigned&to&the&min_tweet&variable.&&

Calls&to&the&save_tweets&function,&using&the&tweets&list&as&an&argument.&This&function&

returns& a& binary& True& or& False& that& is& assigned& to& the& variable& continue_search,&

depending&on&whether&or&not&the&maximum&number&of&tweets&established&has&already&

been&found.&&

Assigns&the&last&tweet&saved&in&the&list&to&the&max_tweet&variable&&

Creates&an&if%loop&in&which:&The&id&of&the&first&and&last&saved&tweets&in&the&tweets&list&are&compared.&If&they&

are&not&the&same,&the&value&of&max_position&is&updated.&&

With& this&new&max_position&value&and& the&same&query&value,&a&new&url& is&

created&by&calling&the&construct_url&function.&&

After&a&delay&marked&by&the&value&of& the&variable&rate_delay,&a&new&JSON&

object&and&therefore&HTML&block&of&tweets&is&saved&in&the&response&variable&

by&calling&to&the&execute_search&function.!Table&11&Description&of&the&functions&of&the&TwitterSearch&class&&

!Variable+Name++ Variable+type+ Variable+description++query! string! keyword!of!interest!outp! string! file!name!of!where!to!save!the!tweets!found!!max_position! int! counter!url! string! URL! encoded! like! the! ones! Twitter’s!

Advanced!Search!Engine!creates!when!a!query!is!introduced.!!

response! JSON!object!! Variable!where!the!JSON!object!of!an!URL!is!saved.!

response[items_html]! HTML!block!! Property! of! the! JSON! object! response!where! all! the! information! for! the! different!tweets!is!saved.!

tweet!! JSON!object! Variable! where! the! software! copies! the!JSON! object! data! extracted! from! the!response[items_html]! property.! This! tweet!object!has!its!own!properties:!user!ID,!user!handle,! username,! date! of! creation,!number!of!retweets,!number!of!favourites.!!

tweets! JSON!list!! List!variable!of!JSON!objects!tweet.!continue_search! binary!! Variable! that! takes! the! value! returned! by!

the!save_tweets!function.!!min_tweet! string! id!of!the!first!tweet!generated!max_tweet! string! id!of!the!last!tweet!generated!Table&12&Description&of&some&of&the&variables&used&in&the&Twitter&Scraper&&

!Then,!a!class!extending!from!TwitterSearch!is!created:!TwitterSearchImpl,!which!needs!the!definition! of! rate_delay! and! error_delay! like! its! parent! class! TwitterSearch,! but! also! of!max_tweets.!This!class!calls! to! the!save_tweets! function!and! implements! the!saving!of! the!tweets!JSON!list!into!an!output!file!established!in!the!outp!variable.!!!!Once!these!two!classes!are!defined,!the!main!function!can!be!implemented.!!!When!a!command!line!is!introduced!in!the!Python!Interpreter,!main!calls!to!the!getopt!function!inside!the!getopt!module!in!order!to!parse!the!options!of!that!command!line!which!is!treated!as!an!argument!list.!Options!refers!to!the!string!of!option!letters!the!script!wants!to!recognize.!In!this!case,!when!the!word!help!is!typed,!the!system!is!exited.!When!the!words!query!or!output!



are! typed,! the! argument! accompanying! them! is! saved! into! the! variables! query! and! outp!respectively.!!!Once! a! value! has! been! assigned! to! the! variables! query! and! outp,! an! object! of! the!TwitterSearchImpl! class! is! created! and! the! search! function! is! called,! passing! the! recently!saved!value!of!the!variable!query!as!an!argument!to!this!function.!As!it!has!already!been!said,!this! search! function! simulates! the! creation! of! the! initial! URL! and! the! URLs! associated! to!loading!new!tweets,!its!actual!search,!parsing!and!saving!into!the!file!established!by!the!outp!variable!until!the!maximum!number!of!tweets!is!reached!or!there!are!no!more!tweets.!!!In! order! to! ensure! that! Twitter! comments! retrieved! correspond! to! a! geographical! area!consistent!with! that!covered!by!the!other!data,! the!geoClocalisation!setting!of! the!Advanced!Search!tool!was!used.!This!feature!allows!to!fix!a!centre!point!and!a!distance!radius,!in!order!to!restrict! the!place!of!emission!of! tweets!to!a!circular!area!fixed!by!those!parameters.!The!centre!point!chosen!corresponds!to!the!coordinates!40.41688,!C3.70244,!which!are!located!at!the!Puerta!del!Sol,!the!city!of!Madrid’s!0!kilometre!(km).!The!radius!was!established!at!8!km.!The!resulting!area!is!represented!in!Image!4.!Though!this!area!is!not!exactly!the!city!of!Madrid,!it!does!cover!the!urban!area!quite!accurately.!!!The! queries! entered! in! the! scraper! correspond! to! the! keywords! listed! in! Table! 13.! These!keywords!were!chosen!in!order!to!cover!not!only!words!related!to!the!air!quality!situation!that!people!might!notice!through!smog!or!other!visible!effects,!but!also!to!cover!health!impacts.!!!Keyword+ Translation+ Keyword+ Translation+contaminación+ pollution! atmósfera! atmosphere!ambiental!+ environment!! nitrógeno! nitrogen!partículas+ particles! ozono! ozone!monóxido!de!carbono+ carbon!monoxide! dióxido!de!sulfuro! sulphur!dioxide!contaminantes+ pollutants! calidad!aire! air!quality!aire!toxico+ toxic!air! trafico!! traffic!!pulmón+ lung! respiración! breath!bronquitis+ bronchitis! inhalar! inhale!enfermo!+ sick! cáncer!pulmón! lung!cancer!alergia+ allergies! asma! asthma!!tos+ cough! garganta! throat!Table&13&First&selection&of&keywords&to&extract&from&Twitter&comments.&&

Summarising,!the!use!of!the!scraper!requires!an!entry!in!the!following!format:!!!python!TwitterScraper.py!Cq!"keyword1+keyword2+...+keywordn"!Cnear!"Madrid"!Cw!"8km"!Cs!"2014C01C01"!Cu!"2014C03C30"!Co!salida_mad_201301_201303.json!!Where!–q!will!be!recognised!as!query,!Cnear!and!–w!are!the!commands!to!identify!the!centre!point!and!the!radius!of!the!area!covered,!Cs!and!–!u!are!the!commands!to!identify!the!starting!date!(since)!and!the!finishing!date!(until)!of!the!collected!tweets.!The!command!–o!identifies!de! output! file!where! the! results!will! be! copied.! This! entry! has! to! be!made! for! every! three!months.!!

Methodology!


!Image&4&Geographical&area&from&which&extracted&tweets&are&posetd.&&

!4.2.4! Holiday!Data!

!Since!this!study!focuses!on!an!urban!environment,!it!seems!appropriate!to!make!a!difference!between!workdays!and!holidays!(both!weekends!and!official!holidays).!Public!holidays!for!2014!and!2015!were!obtained!from!the!official!calendar!at!(calendarioslaborales.com,!2014).!!!

4.2.5! Data!aggregation!!!Once!all!the!data!was!selected,!it!was!aggregated!daily!for!every!day!in!2014!and!2015.!!All!data!collected!covered!different!points!of! the!geographical! region!of! the!city!of!Madrid,!but!once!the!data!was!aggregated,!a!single!value!of!input!variable!was!obtained!as!representative!of! the! situation!of! the!whole! city! in! a! given!date.! Input! variables! are! each!pollutant’s! daily!concentration,!each! ICD’s!daily!hospital! admissions!and!daily!number!of! tweets!containing!each!of!the!selected!keywords.!!!Therefore,!the!value!of!a!pollutant’s!concentration!was!aggregated!from!hourly!to!daily!values!and! from! different! geographical! measurements! to! a! single! one! for! the! city! of! Madrid! by!calculating!its!average!daily!value.!!!The! values! of! hospital! admissions!were! also! gathered! daily! for! all! Hospitals! in! the! city! of!Madrid,!to!produce!a!daily!amount!of!hospital!admissions!for!each!ICD!for!the!whole!city!of!Madrid.!!!The!number!of!tweets!obtained!containing!each!keyword!were!aggregated!daily,!obtaining!a!total!amount!of!daily!tweets!containing!certain!keywords.!!!!!



4.3+ Analytical+techniques++!

4.3.1! Selection!of!techniques!for!bilateral!relationships!!The!time!series!data!was!managed!in!the!RCproject!environment!for!statistical!computing!and!graphics.!!!As! it!was!mentioned!earlier,! one!of! the!goals! of! this! study! is! to! add! to! the!empirical!work!supporting!statements!(i)!the!greater!the!air!pollution!levels,!the!greater!the!health!impacts,!(ii)!the!greater!the!air!pollution!levels,!the!greater!the!social!awareness!and!(iii)!the!greater!the!health! impacts!of!air!pollution,! the!greater! the!social!awareness.! In!order! to!do!so,!bilateral!relationships! between! pollutant’s! concentration! and! hospital! admissions,! pollutant’s!concentration!and!Twitter!messages!and!hospital!admissions!and!Twitter!messages!must!be!established.!However,!the!simple!correlation!is!not!adequate!for!the!data!set!used!in!this!studyf!some! variables! involved,! like! pollutant’s! concentrations! may! affect! others,! like! hospital!admissions,! after! a! delay! of! several! days.! Indeed,! in! (Proyecto! et! al.,! 1999)! the! lag! found!between!pollution!and!mortality!was!up!to!5!days.!This!means!that!the!appropriate!technique!to!use!is!the!lagged!regression.!The!sample!cross!correlation!function!(CCF)!is!widely!used!for!identifying!the!lags!of!the!variable!xt+h!that!affect!yt.!!!CCF!can!help!establish!which!variable!leads!and!which!lags,!depending!on!the!sign!of!h.!In!the!case!where!the!variables!are!xt+h&and!yt,!a!negative!value!of!h!means!that!x&leads!y!while!a!positive!value!of!h!meand!that!x!lags!y.!Furthermore,!CCF!is!used!to!examine!the!x!variable!or!variables!in!order!to!relate!them!to!future!values!of!the!y!variable.!!!In!R,!the!command!for!CCF!is:!!!

ccf!(xC!variable!name,!yCvariable!name,!lags!to!show)!!

This!command!gives!back!the!correlation!between!the!variables!at!each!lag!shown.!Hence,!the! most! suitable! lag! is! the! one! that! presents! the! highest! correlation.! These! results! help!determine!the!time!lag!that!allows!for!the!best!correlation!between!two!variables.!!!It!is!important!to!insist!on!the!fact!that!this!analysis!is!not!a!strict!correlation!analysis!since!the!significance!of!the!relationship,!or!its!pCvalue,!will!not!be!calculated.!This!CCF!analysis!is!made!to!achieve!the!ultimate!goal!of!this!study,!which!is!the!establishment!of!the!forecasting!model!for!hospital!admissions,!and!therefore!all!correlations!made!will!be!directed!to!that!goal.!!!

4.3.2! Selection!of!techniques!for!predictive!model!!!The!results!of!the!CCF!will!not!only!help!find!a!relationship!between!two!variables!but!will!also!be!helpful!in!the!preparation!of!the!input!data!for!a!prediction!model!of!the!variable!hospital&admissions.! Indeed,!a!broader!goal!of!this!study!is!to!try!to!find!a!prediction!model!for!total!hospital!admissions,!and!after!the!CCF,!input!variables!will!be!selected!with!the!time!lag!that!allows!for!its!highest!correlation.!Certainly,!not!all!variables!will!have!a!high!correlation!with!the!output!variable.! Indeed,!variables!with!a!correlation!factor!below!0.2!will!not!be! included!as!input!data!for!the!predictive!model.!Furthermore,!the!model!should!be!as!simple!as!possible!and!therefore!different! input!variables!from!the!selection!of! the!most!correlated!will!be!tried!out,! in!order! to!determine!which!ones!are!effectively!significant! in! reducing! the!error!of! the!model.!!!In!order!to!build!the!forecasting!model,!several!techniques!from!data!mining!will!be!applied.!Data!mining!is!the!computational!process!that!looks!for!patterns!in!large!datasets.!It!can!be!used!for!clustering!–!discovering!groups!and!structures!inside!a!dataset!–,!for!classification!or!regression!among!other!uses.!In!this!case,!data!mining!techniques!will!be!used!for!regression:!

Methodology!


the!goal!is!to!find!a!function!that!models!the!data!with!the!smallest!error.!To!do!this,!supervised!learning! algorithms!will! be! used.!Opposite! to! unsupervised! learning,! these! techniques! use!labelled!data!and!try!to!infer!a!function!from!it.!!!The!first!step!in!the!building!of!a!model!is!the!definition!of!a!training!set,!which!shall!be!made!of!a!vector!of!input!data!and!an!output!value.!Each!pair!of!inputCoutput!data!of!the!training!set!is! a! training! example.! Based! on! this! set,! the! supervised! learning! algorithm! of! choice! will!analyse!the!data!and!create!an!inferred!function.!Once!the!model!is!built,!it!must!be!evaluated.!Indeed,! the!model! is! then!submitted! to!a! test!set!of!data,! from!which!errors!are!calculated.!Since!this!study!is!using!regression,!the!algorithm!with!the!least!error!will!be!the!most!suitable!for!the!forecasting!model.!!!The! algorithms! used! in! this! study! will! be!multiple! linear! regression! (MLR),! support! vector!machine!(SVM),!artificial!neural!net!(ANN)!and!classification!and!regression!tree!(CART)!for!single!models.! Ensemble!models! used!will! be! the! random! forest! (RF),! bagged!CART!and!generalized!boosted!model!(GMB).!Ensemble!models!build!a!higher!performance!regressor!based!on!the!combination!of!basic!regressors!obtained!through!single!models.!Once!the!model!is!built!based!on!the!training!set!for!each!of!the!algorithms,!they!will!be!put!to!test!and!the!one!leading!to!the!least!error!will!be!selected!as!the!forecasting!model.!!!MLR!is!the!algorithm!which!aims!to!establish!the!relationship!between!a!dependent!variable!and!several!independent!or!explanatory!variables!in!the!form!of!an!affine!function,!producing!a! linear!model.! The! linear!model! can! be! fitted! through! several!methods,! namely! the! least!squares! method! which! in! R! is! solved! using! QR! decomposition.! QR! decomposition! is! the!decomposition!of!a!matrix!A!into!the!product!of!QR!where!Q!is!an!orthogonal!matrix!and!R!is!an!upper!triangular!matrix.!!!SVM!is!a!method!that!represents!each!training!example!as!points!in!space!that!are!then!fitted!into!two!hyperplanes!which!are!set!as!far!apart!as!possible.!In!the!SVM,!the!nonClinear!Radial!Basis!Function!is!adopted!as!its!kernel!function.!!!ANN!are!models!based!on!the!operating!method!of!neurones!in!biological!beings.!It!functions!based!on!the!existence!of!layers!of!neurons!that!exchange!data!via!synapses.!In!this!case,!the!number!of!layers!is!set!in!3:!input!layer!containing!input!data,!hidden!layer!and!output!layer!containing!output!data!of! the! training!set.!All!nodes! in! the! layers!are! fully!connected! to! the!nodes!on!the!upper!layer.!The!algorithm!works!by!adjusting!the!weights!between!layers!based!on!the!model!error!calculated!on!each!iteration.!!!CART! algorithm! repeatedly! partitions! the! data! space:! the! initial! data! or! parent! node! is!subsequently!divided!into!child!nodes!based!on!the!results!of!different!evaluation!functions.!This!splitting!is!continued!until!the!terminal!nodes!contain!only!a!few!data!samples.!Methods!based!on!CART!are!also!used!for!analysing!the!importance!of!the!input!variables!in!the!model.!In! this! case,!each!node! is!a! variable!and! the! importance!of! one!variable! is!determined!by!adding!the!improvement!score!of!the!other!nodes!when!the!said!variable!is!used!as!a!splitter.!!!Ensemble!methods!work!by!building!a!set!of!regressors!to!then!obtain!a!single!regressor!of!higher!performance.!In!this!study,!two!of!the!main!existing!ensemble!methods!will!be!exploited:!bagging!and!boosting.!Bagging!consists!of!obtaining,!from!a!single!training!set,!k!new!training!sets!by!sampling!with!replacement!from!the!original!training!set.!Each!training!set!leads!to!a!single!model!fitting!that!are!then!merged!to!obtain!one!basic!learner!for!all!the!sets.!Boosting,!however,! does! not! replicate! the! training! set! but! assigns! different! weights! to! the! training!examples! in!each! iteration,!according! to!whether!or!not! they!were!classified!correctly.!This!generates!different!training!sets!but!not!by!sampling.!The!final!learner!is!obtained!by!combining!the!learners!obtained!on!the!different!iterations.!This!combination!is!usually!done!by!weighting!the!learners!according!to!their!accuracy.!!



!Ensemble!methods!can!therefore!be!applied!to!any!single!model!in!order!to!increase!stability!(by!bagging)!or! to! reduce!variance!(by!boosting).!Since!CART!ensemble!methods!seem!to!have!a!greater!performance!(Gong!&!OrdieresCMeré,!2016),!it!is!the!selected!basic!learner!for!both!bagging!and!boosting!methods!used.!!!Bagging!methods!used! in! this!study!are!bagging!CART!–!which!operates!according! to! the!definition!of!bagging!methods,!using!CART!as!the!basic!learner!–!and!RF.!RF!is!also!a!bagging!method!using!CART!as!its!basic!learner,!but!it!is!limited!to!a!few!features!randomly!selected!in!the!splitting!process.!!!The!boosting!method!used!combines!boosting!with!CART,!as!it!was!stated!above.!In!the!GBM,!the!function!on!which!splitting!is!made!is!a!gradient!descent!algorithm.!!!All!of!these!supervised!learning!methods!will!be!applied!to!the!training!set!obtained!from!the!selected!data.!Then,!each!will!be!evaluated!using!a!test!setf!this!will!lead!to!the!calculation!of!the!models’!errors!measured!through!the!mean!absolute!error!(MAE),!rootCmeanCsquare!error!(RMSE)! and! the! relative! error! (RELE).! The!model! that! leads! to! the! smallest! error! will! be!selected!as!the!forecasting!model.!!!Once!the!model!building!method!is!known,!it!is!interesting!to!evaluate!the!importance!of!the!input!variables!included,!in!order!to!simplify!the!model.!The!importance!of!the!variables!will!be!measured!using!the!RF!method,!which,!as!described!above,!is!suitable!for!this!purpose!since!it!is!a!CARTCbased!method.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Methodology!


!!!



!

5! RESULTS!!!

5.1+ Descriptive+analysis+of+the+situation+in+the+city+of+Madrid+++!

5.1.1! Air!quality!assessment!!!The!statistical!analysis!of!the!pollution!data!is!combined!with!the!legal!limit!values!in!order!to!assess!the!air!quality!of!the!city!of!Madrid!during!2014!and!2015.!Indeed,!Table!14!!represents!the!legal!annual!limits!of!pollutant’s!concentration!in!the!UE,!the!annual!average!calculated!for!both!years!2014!and!2015,!the!first!quartile!(Q1),!the!median,!the!third!quartile!(Q3)!and!the!maximum!values!obtained!in!a!day!during!these!two!years,!all!in!µg/m3.!!!Comparing!these!values,!it!is!evident!that!none!of!the!pollutants’!annual!average!exceeds!the!annual!limit!value,!though!NO2’s!annual!average!of!38,042!µg/m3!

!does!come!close!to!the!40!µg/m3!

!!allowed.!Furthermore,!the!value!of!Q3!being!46,674!µg/m3,!it!can!be!said!that!25%!of!the!days! the! concentration!of!NO2!was!higher! than! the! limit! set.!Nevertheless,! the!median!being!34,317!µg/m3!,!it!can!also!be!said!that!at!least!50%!of!the!days!the!concentration!of!NO2!was!below!the!limit!value.!!!For!the!rest!of!the!pollutants!considered,!75%!of!the!days!during!the!years!studied,!pollutants’!concentrations! were! largely! below! the! annual! average! set,! as! the! values! of! Q3! indicate.!However,!maximum!daily!values!of!both!PM2,5!and!PM10!do!reach!up!to!values!1,44!and!2,27!times!bigger!than!the!limit!values.!!!Pollutant+ Annual+

limit+Annual+Average+

Q1+ Median+ Q3+ Daily+maximum+

O3+ 120! 51.09! 32.71! 52.05! 70.22! 108.44!SO2+ 20! 5.950! 4.292! 5.284! 6.729! 15.588!PM10+ 40! 20.189! 12.874! 18.030! 24.626! 90.879!PM2,5+ 25! 11.115! 7.484! 9.9! 13.404! 36.111!NO2+ 40! 38.042! 24.694! 34.317! 46.674! 105.077!

Benzene+ 5! 1.464! 1.2! 1.406! 1.634! 3.623!Table&14&Statistical&Analysis&of&the&main&pollutants&

Furthermore,! in! order! to! assess! the! pollutants! in! time,! time! series! representing! the! key!pollutants’!PM2,5,!NO2,!O3!and!SO2!concentration!against!time!were!created.!Results!are!shown!in!Figure!1,!Figure!2,!Figure!3!and!Figure!4.!!!First!of!all,!it!is!quite!obvious!that!no!significant!progress!has!been!made!in!the!reduction!of!any!pollutant!on!the!course!of!these!two!yearsf!quite!the!opposite,!SO2!values!seem!to!have!risen.!However,! this! lack!of! improvement! is!not!as!alarming!as! it!may!seem,!since!most!air!pollution!abatement!measures!are!created!for!long!term!results.!Indeed,!the!latest!UE!Directive!to!“clean!up!Europe’s!air”!(European!Commission,!2013)!was!approved!in!2013!but!sets!its!goals!in!the!air!quality!of!2030.!!!

Results!!


!Figure&1Daily&evolution&of&&NO2&concentration&in&2014&and&2015&

!

!Figure&2&Daily&evolution&of&O3&concentration&in&2014&and&2015&

!Figure&3&Daily&evolution&of&PM2,5&concentration&in&2014&and&2015&

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!Figure&4&Daily&variation&of&SO2&concentration&in&2014&and&2015&

!In!the!NO2,!O3!and!SO2!graphs,!there!is!a!more!or!less!pronounced!seasonality.!NO2!and!O3!have! a! pronounced! seasonality! pattern.! NO2! concentration! presents! peaks! in! the! winter!months,!while!its!lows!are!in!the!summer.!On!the!contrary,!O3!concentrations!reach!their!peaks!in! the! summer! months! and! their! lows! in! the! winter.! Indeed,! NO2! and! O3! values! are! not!independent.!O3! is!formed!from!several!precursors,! including!NO2,!and!the!reaction! implied!needs! sunlight! in! order! to! occur.! This! explains! why! O3! levels! are! highest! in! the! summer!months,!where!there! is!more!sunlight,!and!slowly!decrease!after! the!summer!to!reach!their!lowest! in!November,!December!and!January.! In! the!winter!months,!NO2! is!not! transformed!into!O3!and! therefore! its! concentration! is! higher.! Therefore,! peaks! and! lows! are! not! really!related!to!lower!or!higher!emissions!of!a!pollutant!but!rather!to!meteorological!conditions.!!!The!seasonality!in!SO2!is!not!as!marked,!but!there!seems!to!be!a!constant!period!from!April!to!October!where!concentration!stays!in!lower!values!–!around!4!µg/m3!in!2014!and!below!6!µg/m3!in!2015,!and!with!little!deviation!that!contrasts!with!a!more!irregular!period!lasting!from!November!to!March.!In!this!second!period,!concentration!reaches!a!higher!range!of!values!–!above! 6! µg/m3! and! reaching! 15! µg/m3,! but! also! deviation! is! bigger.! The! highest! values!registered!correspond!to!December!and!January.!SO2!emissions!are!related!to!coal!or!fossil!fuel!burning!in!heating!or!power!plants.!Indeed,!the!peak!of!SO2!concentrations!in!the!colder!months!could!be!due!to!a!higher!heating!demand!during!that!time.!Here,!contrarily!to!NO2!and!O3,!peaks!do!seem!to!be!related!to!higher!pollution.!!!Going! back! to! the! increased! values! of! SO2! concentrations! in! 2015,! this! is! supported! the!Statistical!Review!of!World!Energy!carried!out!by!(BP,!2016).!Indeed,!Spain!is!the!country!that!increases!the!most! its!coal!consumption!from!2014!to!2015,!with!a!growth!of!23,9%.!While!coal! consumption! had! been! decreasing! since! 2005,! in! 2010! coal! consumption! reaches! its!lowest!and!increases!again!until!today.!Oil!consumption!also!increases!from!2014!to!2015,!but!in!a!2,6%.!However,!consumption!of!hydroelectricity!dropped!28%!and!renewable!energies!dropped! 4%! in! that! time.! Simultaneously,! the! price! of! oil! barrels! and! of! coal! tonnes! also!dropped!from!2014!to!2015!for!the!first!time!since!2009!–!down!to!a!48%!and!a!29,6%!reduction!for!oil!and!coal!respectively.!The!choice!of!a!cheaper!energy!source!in!the!economic!situation!of!Spain!seems!to!be!a!very!likely!explanation!for!this!SO2!rise.!!!However,!PM!values!do!not!present!any!evident!seasonality!pattern.!It!is!the!pollutant!which!has!the!most!deviation.!Its!highest!value!in!the!time!studied!is!reached!in!December!2015.!On!the!last!months!of!2015!values!seem!to!oscillate!around!higher!values!than!previously.!PM!is!

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Results!!


the! focus! of! many! of! the! latest! legislation! efforts.! It! is! a! considerably! new! and! confusing!pollutant,!due!to!its!wide!definition.!!!

5.1.2! Hospital!admissions!assessment!!!The! statistical! analysis! of! hospital! admissions! in! the! public! hospitals! of! the! city! of!Madrid!locates! the!average!of!daily!admissions! in!1386.!During!2014!and!2015,!75%!of! the!days,!hospitals!admitted!more!than!1000!patients!and!25%!of!the!days,!admissions!were!over!1774.!Figure!5!represents!the!daily!evolution!of!hospital!admissions!in!those!two!years.!There!is!an!obvious!valley!in!the!summer!and!in!the!Christmas!months.!MidCJune!admissions!decrease,!they!reach!their!lowest!in!August!and!start!growing!through!Septemberf!similarly,!admissions!decrease! half! way! through! December! until! midCJanuary.! ! Indeed,! during! the! summer! and!Christmas! holidays! people! tend! to! abandon! the! urban! environment.! The! influence! of! the!summer!holidays!is!also!visible!in!the!admissions!for!ICDs!related!to!cardiovascular!diseases!and!in!a! lesser!way! in!the!admissions!for!respiratory! issues,!as! it! is!shown!in!Figure!8!and!Figure!7!respectively.!!!Mortality!presents!a!clear!peak!in!the!winter!months,!as!shown!in!Figure!6.!This!is!a!seasonality!confounder:!mortality!usually!increases!in!the!winter!because!of!influenza!epidemics.!Hence,!this! rise! in! mortality! cannot! be! attributed! to! air! quality! issues.! Indeed,! this! peak! is! also!noticeable! in! admissions! for! respiratory! issues! (Figure! 7):! influenza! and! other! respiratory!diseases!are!more!prone!to!appear!in!the!colder!monthsf!pollution!does!not!play!a!role!in!these!trends.!!!!

!Figure&5&Daily&evolution&of&hospital&admissions&in&2014&and&2015&&

Besides! the!notable! influence!of!meteorological!conditions! in! the!development!of!diseases,!total!admissions,!mortality!and!admissions!for!cardiovascular!diseases!(Figure!8)!appear!to!be!quite!evenly!distributed!throughout!the!year.!

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!Figure&6&Daily&evolution&of&mortality&for&all&causes&in&2014&and&2015&&

!Respiratory! issues,! however,! present! very! pronounced! peaks! and! valleys.! A! possible!explanation!is!that!temperature!has!a!higher!influence!on!respiratory!issues!than!in!the!other!diagnosis.!However,!respiratory!issues!are!also!the!most!intuitively!related!to!air!quality!and!the!pattern!in!Figure!7!reminds!of!the!evolution!pattern!of!NO2!and!to!the!inverse!of!O3.!Further!bilateral!correlations!could!present!a!relationship!between!these!variables.!!!!

!Figure&7&Daily&evolution&of&hospital&admissions&for&respiratory&issues&in&2014&and&2015&

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Results!!


!Figure&8&Daily&evolution&of&hospital&admissions&for&cardiovascular&disease&in&2014&and&2015&

!Since! one! of! the! goals! of! this! study! is! to! help! hospitals! achieve! a! better!management! by!obtaining!a!model!that!can!predict!admissions,!data!precisely!from!admissions!was!used!to!asses!current!hospital!situation.!!!First,!mortality!was!compared!during!workdays!and!during!holidays,!as!shown!in!Figure!9,!as!previous! observation! indicated! a! clear! influence! of! holiday! periods! in! hospital! admissions.!Mortality!seems!to!follow!the!same!pattern!in!workdays!and!holidays,!but!the!mortality!absolute!values!are!clearly!lower!in!the!holidays.!!!

!Figure&9&Daily&mortality&on&workdays&and&on&holidays&in&2014&and&2015&

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4060

8010

0

All mortality

2014−01−01

2014−02−01

2014−03−01

2014−04−01

2014−05−01

2014−06−01

2014−07−01

2014−08−01

2014−09−01

2014−10−01

2014−11−01

2014−12−01

2015−01−01

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2015−03−01

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2015−05−01

2015−06−01

2015−07−01

2015−08−01

2015−09−01

2015−10−01

2015−11−01

2015−12−01

●

●

workdaysholidays



!However,!a!better!evaluation!should!measure!mortality!values!relative!to!total!admissions.!This!analysis! is!presented! in!Figure!10!and!also!distinguishes!between!workdays!and!holidays.!From!this!it!can!be!argued!that!during!the!holidays,!mortality!rates!is!higher!than!on!workdays.!This!means! that! on!workdays!more! people! are! admitted! into! the! hospital! that! do! not! die,!compared!to!holidays.!Effectively,! it!seems!as!though!people!that!go!to!hospitals!on!festive!days!are!more!seriously!ill!than!those!that!attend!it!on!workdays.!Indeed,!it!can!be!concluded!that! the!percentage!of! overCuse!of! the!emergency! services! in!hospitals! in! an!unnecessary!manner!is!greater!on!workdays!than!on!holidays.!!!!!

!Figure&10&Daily&mortality&relative&to&daily&hospital&admissions&on&workdays&and&holidays&in&2014&and&2015&

!5.1.3! Twitter!messages!related!to!pollution!assessment!!

!Twitter!messages!containing!all!keywords!shown!in!Table!13!where!searched!for!using!the!scraper!but,!not!all!of!them!corresponded!to!considerably!large!amounts!of!tweets.!Therefore,!only!a!few!were!selected!as!actual!input!data!for!the!study.!Table!15!shows!the!selected!keywords!and!the!volume!of!messages!containing!them!in!the!timespan!of!this!study.!!!

+SPANISH+

Word+ nº+of+tweets+ daily+mean+ Q1+ median+ Q3+aire! 13!144! 18.01! 6! 16! 25!

garganta! 6!009! 8.232! 2! 7! 12!tos! 3!193! 4.374! 1! 4! 7!

enfermo! 2!244! 3.074! 1! 2! 5!respiración! 1!057! 1.448! 0! 1! 2!

contaminación! 562! 0.7699! 0! 0! 1!ambiental! 190! 0.2603! 0! 0! 0!inhalar! 12! 0.01644! 0! 0! 0!

+ENGLISH++

air+ 6!031+ 8.262+ 3! 8+ 12!

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0.04

0.05

0.06

0.07

0.08

All mortality/all admissions

2014−01−01

2014−02−01

2014−03−01

2014−04−01

2014−05−01

2014−06−01

2014−07−01

2014−08−01

2014−09−01

2014−10−01

2014−11−01

2014−12−01

2015−01−01

2015−02−01

2015−03−01

2015−04−01

2015−05−01

2015−06−01

2015−07−01

2015−08−01

2015−09−01

2015−10−01

2015−11−01

2015−12−01

●

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workdaysholidays

Results!!


sick! 1!252! 1.715! 0! 1! 3!breath! 730! 1.00! 0! 1! 1!

environment! 457! 0.6178! 0! 0! 0!throat! 97! 0.1329! 0! 0! 0!cough! 71! 0.09726! 0! 0! 0!pollution! 67! C! C! C! C!inhale! 29! 0.03973! 0! 0! 0!

Table&15&Statistical&analysis&of&tweets&containing&certain&keywords&related&to&air&pollution&and&its&health&effects&

!The!most!popular!word!in!Twitter!messages!related!to!air!quality!is,!not!surprisingly,!“aire”,!the!Spanish! word! for! air.! Following! that! come! the! Spanish! words! expressing! symptoms! and!discomforts:! “garganta”,! “tos”,! “enfermo”! and! “respiración”! refer! to! throat,! cough,! sick,! and!breath!respectively.!It!is!only!after!these!health!related!words!that!come!words!directly!linked!to! air! quality:! “contaminación”,! “ambiental”,! “calidad! aire”! and! “inhalar”! correspond! to! the!English!words!pollution,!environmental,!air!quality!and!inhale.!These!results!coincide!with!the!existing!literature!concerning!social!awareness!of!air!pollution.!Indeed,!social!assessment!of!air!pollution!is!done!through!sensorial!evidence:!first!through!personal!experience!–!including!discomforts!and!health!effects,!then!through!visual!effects!in!the!atmosphere.!This!could!also!be!evidence!of!the!low!social!awareness!of!the!health!impacts!of!air!pollution!since!symptoms!are!identified!but!not!linked!to!air!quality.!!!Furthermore,!all!Spanish!words!expressing!respiratory!discomforts!but!the!word!“respiración”!itself!have!positive!values!for!the!first!quartile.!This!means!that! in!75%!of!the!days!studied,!there!were!at!least!2!to!25!Twitter!messages!in!the!city!of!Madrid!containing!these!words.!The!word! “respiración”! is!present! in!at! least!one!Twitter!comment!50%!of! the!days!considered.!However,!words!that!relate!directly!to!air!pollution!are!not!mentioned!nearly!as!much:!though!“contaminación”!is!mentioned!25%!of!the!days!in!at!least!one!Twitter!message,!the!rest!of!the!air!quality!related!words!do!not!appear!in!at!least!75%!of!the!messages.!!To!try!to!make!a!better!assessment!of!what!the!Twitter!messages!indicate,!some!graphs!were!made.!First,!the!two!most!popular!Spanish!words!“aire”!and!“garganta”!were!plotted.!Then,!the!second!most!popular!English!word,!“sick”,!was!also!plotted.!Finally,!since!“contaminación”!is!the!most!directly!related!word!to!air!quality!but!it!doesn’t!seem!to!be!very!popular!in!Twitter!messages,!it!was!considered!as!interesting!to!evaluate!it!further.!It!was!also!plotted.!Results!are!shown!in!Figure!11,!Figure!12,!Figure!13!and!Figure!14!

&

Figure&11&Daily&evolution&of&the&volume&of&tweets&containing&the&keyword&“aire”&

050

100

150

aire

volu

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of m

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ges

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1

2014−02−0

1

2014−03−0

1

2014−04−0

1

2014−05−0

1

2014−06−0

1

2014−07−0

1

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1

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2015−12−0

1



!Figure&12&Daily&evolution&of&the&volume&of&tweets&containing&the&keyword&“garganta”&

!Figure&13&Daily&evolution&of&the&volume&of&tweets&containing&the&keyword&“sick”&

!Figure&14&Daily&evolution&of&the&volume&of&tweets&containing&the&keyword&“contaminación”&

In!all!four!graphs,!there!is!a!certain!decreasing!tendency.!It!is!the!most!obvious!in!the!case!of!the!volume!of!messages!containing! the!word!“garganta”.!During!2014!and!even!up! to!April!2015,!the!daily!volume!of!messages!does!not!seem!to!go!below!5very!often!and!is!quite!likely!

010

2030

40

garganta

volu

mn

of m

essa

ges

2014−01−0

1

2014−02−0

1

2014−03−0

1

2014−04−0

1

2014−05−0

1

2014−06−0

1

2014−07−0

1

2014−08−0

1

2014−09−0

1

2014−10−0

1

2014−11−0

1

2014−12−0

1

2015−01−0

1

2015−02−0

1

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1

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1

2015−05−0

1

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1

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1

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1

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1

2015−11−0

1

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1

010

2030

4050

60

sick

volu

mn

of m

essa

ges

2014−01−0

1

2014−02−0

1

2014−03−0

1

2014−04−0

1

2014−05−0

1

2014−06−0

1

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1

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1

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1

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1

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1

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1

2015−01−0

1

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1

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1

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1

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1

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1

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1

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1

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1

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1

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1

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1

05

1015

20

contaminacion

volu

mn

of m

essa

ges

2014−01−0

1

2014−02−0

1

2014−03−0

1

2014−04−0

1

2014−05−0

1

2014−06−0

1

2014−07−0

1

2014−08−0

1

2014−09−0

1

2014−10−0

1

2014−11−0

1

2014−12−0

1

2015−01−0

1

2015−02−0

1

2015−03−0

1

2015−04−0

1

2015−05−0

1

2015−06−0

1

2015−07−0

1

2015−08−0

1

2015−09−0

1

2015−10−0

1

2015−11−0

1

2015−12−0

1

Results!!


to!go!over!10!and!even!15!messages!a!day.!However,! from!May!2015!onwards,! the!daily!volume!of!messages!containing!“garganta”!as!a!key!word!hardly!ever!reach!5.!Likewise,!but!in!a! less!dramatic!way,!number!of! tweets!containing! the!keyword! “aire”!seem! to!drop! from!oscillating!around!15!daily!tweets!to!less!than!10.!!!In!the!case!of!the!volume!of!daily!tweets!containing!the!words!“sick”!and!“contaminación”,!the!decreasing! tendency! is! identified! in! the! presence! of! several! days! with! not! a! single! tweet!containing!the!keywords!in!question.!This!results!in!horizontal!lines!clearly!visible!in!the!last!quarter!of!the!period!considered.!!!This!reduction!of!daily!volume!of!tweets!could!be!explained!by!the!fact!that!as!of!the!20th!of!April!of!2015,!Twitter!changed!the!settings!of!their!Direct!Message!feature!(Twitter!Inc.,!2015).!Indeed,!the!microblogging!service!allows!its!users!to!post!public!tweets!that!all!other!users!can!see,!but!it!also!allows!to!send!a!private!message!to!a!unique!user,!which!is!known!as!a!Direct!Message.!Before,!in!order!for!a!certain!to!contact!another!user!through!a!Direct!Message,!the!receiver!of!the!message!had!to!be!following!the!issuer.!From!the!20th!of!April!until!today,!the!issuer!could!send!Direct!Messages!to!any!user!whose!account!settings!enabled!him!to!receive!these!messages!from!any!other!user,!independently!of!the!issuer!following!the!receiver!or!not.!This!new!setting!could!mean!that!tweets!sent!to!popular!and!important!accounts!like!celebrities!or! institutions!where!probably!replaced!by!Direct!Messages,! in!the!thought!of!being!a!more!likely!way!to!reach!their!recipient.!!!!Another!event!related!to!Twitter!during!April!2015!was!the!fall!of!its!stock!to!the!lowest!point!since!its!initial!public!offering,!due!to!the!previous!publication!of!a!tweet!presenting!Twitter’s!not!so!attractive!earnings!in!the!first!quarter!of!the!year.!This!is!very!unlikely!to!have!affected!the!volume!of!daily!tweets!in!the!city!of!Madrid!!!Furthermore,!all!of!these!graphs!appear!to!have!the!same!particularity:!they!oscillate!around!a!range!of!numbers!of! tweets!per!day!in!a!quite!even!manner!but!there! is!at! least!one!day!where!the!number!of!messages!seems!to!be!totally!out!of!scale.!In!order!to!better!understand!what!happened!on!these!particular!dates!in!order!to!provoke!a!remarkable!response!in!Twitter,!the!content!of!the!messages!have!been!evaluated!further.!!&

5.2+ CCF+results+!In!order!to!fulfil!the!first!objective!of!this!monography,!a!CCF!analysis!was!carried!out!between!the!most! significant! variables! of! the! three!aspects! discussed.!Taking! into! account! that! the!ultimate!target!of!this!study!is!to!establish!the!forecasting!model!in!the!following!section,!and!that!in!order!to!do!so!variables!must!be!correlated!to!the!total!number!of!hospital!admissions,!in!all!correlations!involving!public!health!presented!below,!it!will!be!represented!exclusively!by!the!variable!yt!=!number!of! total!admissions.!As! it!was!mentioned!earlier,! the!CCF!analysis!aims!to!find!the!lag!h!that!allows!for!the!best!correlation!between!the!variables!analysed.!!!

5.2.1! Correlation!between!air!pollution!and!public!health!!!Pollutants! considered! in! this! correlation! analysis! are! the! ones! that! presented!a! correlation!coefficient! higher! than! 0,1.! These! coincide!with! the! pollutants! that! currently! hold! the!most!attention!in!studies!and!legislation:!O3!and!PM.!The!CCF!results!are!presented!in!Figure!15,!Figure!16!and!Figure!17.!!!In! all! three! cases,! the! highest! correlation! coefficients! seem! to! be! negative.! A! negative!correlation! coefficient! between! these! variables! means! that! when! the! concentration! of!pollutants!increases,!the!number!of!total!admissions!decreases.!This!relationship!goes!against!what!was!suggested!in!the!first!statement!(i)!the!greater!the!air!pollution!levels,!the!greater!the!health!impacts.!!



!

!Figure&15&CCF&results&for&O3&concentration&&and&hospital&admissions&for&all&causes&&

!

!Figure&16&CCF&results&for&PM2,5&concentration&and&hospital&admissions&for&all&causes&&

!!However,!in!order!to!completely!disregard!the!validity!of!statement!(i),!the!actual!values!of!the!highest! correlation! coefficient! and! the! corresponding! lag! must! be! analysed.! These! are!presented!in!Table!16.!!!!

Pollutant+(xt+h)+ Correlation+Coefficient+ Lag+in+days+(h)+O3! C0,18123! C14!PM2,5! C0,15575! C9!PM10! C0,20355! C9!

Table&16&Highest&correlation&coefficient&and&corresponding&lag&for&correlations&between&pollutants’&concentration&

and&hospital&admissions&for&all&causes&&

!

−20 −10 0 10 20

−0.1

5−0

.10

−0.0

50.

000.

05

Lag

ACF

O3 VS Total Admission

−20 −10 0 10 20

−0.1

5−0

.10

−0.0

50.

000.

050.

100.

15

Lag

ACF

PM2.5 VS Total Admission

Results!!


The!values!of! the!correlation!coefficients!are! in!all! three!cases!very! low! indicating! that! the!number!of!total!hospital!admissions!does!not!depend!strongly!on!isolated!measurements!of!pollutants’!concentration.!So,! taking! into!consideration! the!absolute!value!of! the!correlation!coefficient!and!its!sign,!it!can!be!stated!that!even!if!the!results!do!not!support!statement!(i),!the!coefficients!found!are!not!strong!enough!in!order!to!support!the!opposite!statement:!the!greater!the!air!pollution!levels,!the!lower!the!health!impacts.!!!This!weak!relationship!between!the!total!number!of!hospital!admissions!could!be!explained!by!the!fact!that!statement!(i)!refers!to!pollution!as!a!whole!and!not!to!the!concentration!of!a!single!pollutant!against!the!total!number!of!hospital!admissions!for!all!causes.!Indeed,!maybe!it!would!be! more! accurate! to! study! the! correlation! between! pollution! (measured! in! a! way! that! all!pollutants!are! taken! into!account)!and!total!admissions!or!between!a!single!pollutant!and!a!single! diagnosis! for! admission.! Another! option!would! be! to! compare! pollution! to!mortality,!which,! as! the! literature! suggests,! is! an! easier! relationship! to! establish! than! to! morbidity.!However,!considering!the!final!target!of!this!study!–!which!is!to!build!a!forecasting!model!for!hospital!admissions,!these!other!correlations!have!not!been!carried!out.!!!Furthermore,!the!lags!are!also!negative!values.!This!means!that!the!concentration!of!O3!has!the!highest!influence!on!hospital!admissions!14!days!laterf!the!concentration!of!all!PM!types!has!the!highest!influence!on!hospital!admissions!9!days!later.!!Indeed,!since!h!has!a!negative!value,!it!can!be!said!that!concentration!of!O3!and!PM!lead!the!number!of!hospital!admissions.!!!

!Figure&17&CCF&results&for&PM10&concentration&and&hospital&admissions&for&all&causes&&

The!air!pollution!dispersion!is!affected!by!meteorological!variables.!Therefore,!an!analysis!of!the!air!quality!is!not!complete!if!these!variables!are!not!taken!into!consideration.!The!results!of!the!CCF!analysis! is! presented! in!Table! 17.!While! the! variables! temperature,! humidity! and!pressure!present!correlation!coefficients!with!values!similar!in!magnitude!to!the!pollutants’,!the!wind!speed!variable!can!be!disregarded,!since!it!is!especially!low.!!!Furthermore,! it! seems! that! temperature! and! pressure! present! a! negative! correlation!coefficient.!This!means!that!when!temperature!and!pressure!rise,!hospital!admissions!lower.!Indeed,! this! relationship! had! already! been! stated! between! temperature! and! hospital!admissions! in! the! descriptive! analysis:! mortality! increased! in! the! colder! months! due! to!influenza! like!epidemics.!When!pressure! lowers,!air! rises!and!cools!as! it!ascends,! forming!clouds! and! even! precipitation.! These! weather! conditions! would! be! associated! to! higher!hospital!admissions,!according!to!these!results.!!

−20 −10 0 10 20

−0.2

0−0

.15

−0.1

0−0

.05

0.00

0.05

0.10

Lag

ACF

PM10 VS Total Admission



!!In!any!case,!the!lags!are!all!negative:!meteorological!conditions!lead!hospital!admissions.!It!seems!that!pressure!has!an!effect!on!hospital!admissions!much!faster!in!time!–!2!days!–than!temperature!and!humidity,!which!can!take!up!to!24!days!to!influence!hospital!admissions.!!!Again,!though!the!relationship!is!not!the!strongest,!it!can!be!admitted!that!there!exists!a!certain!relationship!between!meteorological!variables!and!hospital!admissions.!!!

Meteorological+variable+(xt+h)% Correlation+Coefficient+ Lag+h+(in+days)+Temperature! C0,17758! C24!Humidity! 0,156952! C20!

Wind!Speed! 0,066199! C3!Pressure! C0,10073! C2!

Table&17&Highest&correlation&coefficient&and&corresponding&lag&for&correlations&between&meteorological&variables&

and&hospital&admissions&for&all&causes&&

5.2.2! Correlation!between!Twitter!messages!and!air!pollution!!In!order!to!establish!the!level!of!social!awareness!about!air!quality,!the!correlation!between!representative!pollutants!and!keywords!was!made.!The!chosen!pollutants!are!once!again!O3!and!PM.!!Since!O3!is!related!to!cough!days!(Künzli!et!al.,!2000),!the!CCF!analysis!was!run!between! O3! and! the! Spanish! translation! of! cough,! “tos”,! which! is! the! third! most! popular!keyword!amongst!those!studied,!with!at!least!one!daily!tweet!containing!it!in!75%!of!the!days!studied.!Furthermore,!a!CCF!analysis!was!conducted!between!the!same!keyword!and!PM10!while! the! keyword! “air”! was! analysed! along! the! pollutant! PM2,5.! Results! are! shown! in! the!following!Figure!18!and!Table!18.!!

!

!Figure&18&CCF&results&for&pollutants&and&Twitter&messages&&

Pollutant+(xt+h)% Correlation+Coefficient+ Lag+h+(in+days)+yt=!tos!

O3! C0,15! C19!PM10! C0,2! 0!

yt=!air!PM2,5! C0,15! 0!

Table&18&Highest&correlation&coefficient&and&corresponding&lag&for&correlations&between&Twitter&messages&and&air&

pollution&&

−20 −10 0 10 20

−0.1

5−0

.10

−0.0

50.

000.

05

Lag

ACF

O3 VS twitter:tos

−20 −10 0 10 20

−0.2

0−0

.15

−0.1

0−0

.05

0.00

0.05

Lag

ACF

PM10 VS twitter:tos

−20 −10 0 10 20

−0.1

5−0

.10

−0.0

50.

000.

05

Lag

ACF

PM2.5 VS twitter:air

Results!!


The! correlation! coefficients! between! Twitter! keywords! related! to! air! quality! and! its! health!effects!and!pollutants’!concentration! levels! in! the!air!are!negative!values.!This!means! that,!according!to!the!results!of!the!CCF!analysis,!when!the!concentration!of!pollutants!increases,!the!presence!of!related!keywords!in!published!tweets!decreases.!Therefore,!the!results!seem!to!go!against!statement!(ii)!the!greater!the!air!pollution!levels,!the!greater!its!social!awareness.!However,!and!similarly!to!the!relationship!between!air!pollution!and!public!health,!the!absolute!values!of!the!correlation!coefficients!are!not!big!enough!to!indicate!strong!relationship!between!the! variables! and! therefore! to! accept! the! opposite! statement,! the! greater! the! air! pollution!levels,!the!lesser!its!social!awareness,!as!a!true!statement.!!!However,! it! is! interesting! to! point! out! that! the! best! correlation! between!PM!pollutants! and!tweets!was!found!with!a!lag!h=0.!This!means!that!the!variation!of!PM!is!simultaneous!to!the!variation!of!daily!tweets!related!to!air!pollution!and!health!impacts.!This!is!not!the!case!for!O3!levels,!which!lead!the!twitter!comments!with!a!lag!of!h=C19!days.!From!the!value!of!the!lags!and!the!correlation!coefficients,!one!can!conclude!that!PM!is!more!effectively!assessed!by!the!lay!public!than!O3.!!!

5.2.3! Correlation!between!Twitter!messages!and!public!health!!In! the!analysis!of! finding!a! relationship!between!public!health!and!Twitter!messages,!each!keyword!that!produced!a!considerable!volume!of!tweets!was!submitted!to!the!CCF!analysis.!Results!of! the!keywords! in!Spanish!and!English!that!presented!a!correlation!higher!than!or!equal!to!0,1!are!presented!in!Figure!19.!!!!!

!!!

−20 −10 0 10 20

−0.0

50.

000.

050.

100.

150.

20

Lag

ACF

twitter:tos VS Total Admission

−20 −10 0 10 20

−0.1

0−0

.05

0.00

0.05

0.10

0.15

Lag

ACF

twitter:garganta VS Total Admission

−20 −10 0 10 20

−0.1

0−0

.05

0.00

0.05

0.10

0.15

Lag

ACF

twitter:contaminacion VS Total Admission



!

!!

!

!

!Figure&19&CCF&results&for&Twitter&messages&and&hospital&admissions&for&all&causes&&

Spanish!words!that!did!not!present!a!correlation!higher!than!0,1!include!“aire”!–!that!produced!the!highest!volume!of!daily!tweets,!“enfermo”!and!“inhalar”.!!The!fact!that!“inhalar”!does!not!present!even!a!small!correlation!is!not!that!surprising,!since!they!produced!a!very!low!volume!of! tweets.!However,! it! is!quite!striking! that! the!word! “enfermo”!which!means!sick,!does!not!present!any!correlation!with!hospital!admissions!for!all!causes.!This!relationship!was!expected!to!be!quite!strong!since!it! is!a!generic!word,!commonly!used.!Finally,!the!fact!that!the!word!“aire”!produced!the!largest!daily!volume!of!tweets!but!does!not!present!even!a!small!correlation!

−20 −10 0 10 20

−0.0

50.

000.

050.

10

Lag

ACF

twitter:respiracion VS Total Admission

−20 −10 0 10 20

−0.0

50.

000.

050.

100.

15

Lag

ACF

twitter:air VS Total Admission

−20 −10 0 10 20

−0.1

0−0

.05

0.00

0.05

0.10

Lag

ACF

twitter:environment VS Total Admission

−20 −10 0 10 20

−0.0

50.

000.

050.

10

Lag

ACF

twitter:throat VS Total Admission

−20 −10 0 10 20

−0.0

50.

000.

050.

10

Lag

ACF

twitter:sick VS Total Admission

Results!!


with! hospital! admissions! comes! to! show!what! other! studies! in! the! literature! have! already!shown:!there!is!a!lack!of!association!between!air!pollution!and!health!impacts!on!oneself.!!!English!words!in!the!same!situation!are!“breath”,!“cough”,!“pollution”!and!“inhale”.!!In!this!case,!the!words!“cough”,!“pollution”!and!“inhale”!produced!very!few!daily!tweets!and!therefore!were!not!expected!to!be!strongly!correlated!to!hospital!admissions.!The!word!“breath”!was!the!third!most!popular!English!keyword,!but!even!so!had!a!mean!value!of!1!tweet!per!day.!This!does!not!seem!enough!to!expect!a!significant!relationship!with!hospital!admissions.!!!In! this! case,! contrarily! to! the! two! previous! correlation! studies,! the! highest! correlation!coefficients!seem!to!be!positive!in!all!cases.!A!positive!correlation!coefficient!means!that!if!the!daily!volume!of!tweets!containing!one!of!the!selected!keywords!increases,!the!number!of!total!admissions! increases.!These! results!would! therefore!create!evidence!supporting!statement!(iii)!the!greater!the!health!impacts!of!air!pollution,!the!greater!its!social!awareness.!!!However,! the!absolute!value!of! the!highest!correlation!coefficients!must!also!be! taken! into!accountf!they!are!presented!in!Table!19.!!!

Keyword+(xt+h)+ Correlation+Coefficient+ Lag+h%(in+days)+tos! 0,192473! C8!

garganta! 0,175398! C15!contaminación!! 0,159941! C14!respiración!! 0,134284! C8!!

air! 0,186789! C15!environment! 0,098378! C7!

throat! 0,096309! C21!sick! 0,134173! C2!

ambiental!! 0,112714! C14!!& Table&19&Highest&correlation&coefficient&and&corresponding&lag&for&correlations&between&Twitter&messages&

and&hospital&admissions&&

!Most!of!these!values!stay!between!0,13!and!0,2!in!the!best!case!scenario,!and!sometimes!do!not!reach!0,10.!The!best!correlation!is!found!for!messages!containing!the!keyword!“tos”,!which!is!the!Spanish!word!for!cough,!with!a!correlation!coefficient!of!0,192473.!Following!that!comes!“garganta”,!that!means!throat.!These!two!words!are!related!to!symptoms!and!so!are!4!out!of!the!6!keywords!that!presented!a!correlation!coefficient!higher!than!0,1.!Only!2!words!refer!to!actual!air!quality!conditions.!This!comes!to!show!once!more!that!the!lay!public!does!not!yet!make! a! clear! link! between! air! pollution! and! its! health! impactsf! lower! association! is!made!between! air! pollution! related! words! and! hospital! admissions! than! in! the! casa! of! health!discomforts,!which!are!based!on!direct!experience.!!!Once!more,!these!low!values!of! the!correlation!coefficient!come!to!show!that!there! is!not!a!strong!relationship!between!daily!volume!of!tweets!containing!single!keywords!and!number!of!hospital!admissions.!Hospital!admissions!cannot!be!solely!determined!by!comments!in!Twitter!and!though!the!direct!relationship!between!both!variables!is!weak,!it!certainly!exists.!Moreover,!it!is!interesting!to!point!out!that!out!of!the!three!CCF!analysis!carried!out,!only!this!one!presents!the! expected! direction,! which! is! a! positive! one.! This! realization! places! social! media! as! a!potential!public!health!sensor!tool!on!the!rise.!!!Moreover,!the!values!of!the!lags!h&that!allow!for!the!best!correlation!are!negative!in!all!cases.!This! means! that! Twitter! comments! containing! certain! keywords! lead! hospital! admissions.!Therefore,! although! the! values! of! the! correlation! coefficients! suggest! that! the! direct!relationship!between!single!keywords!and!hospital!admissions!is!not!strong,!the!value!of!the!lag!suggests!that!social!complaints!about!air!quality!conditions!or!its!health!effects!come!before!



the!hospital!admission.!Hence,!combined!with!other!variables,!these!results!could!help!forecast!hospital!admissions.!!!!!

5.2.4! Conclusions!of!the!CCF!results!!The!results!of! the!CCF!analysis! for! the!bilateral! relationship!between!air!pollution!and!both!hospital!admissions!and!twitter!comments!do!not!reveal!the!expected!direction!and!therefore!cannot! be! considered! to! add! to! the! empirical! body! of! work! mentioned! in! the! objectives’!definition.!In!the!case!of!the!relationship!between!Twitter!comments!and!hospital!admissions,!the! direction! of! the! correlation! is! what! was! expected.! Social! awareness! of! air! pollution!increases! with! increasing! health! impacts.! Though! the! strength! of! this! relationship! is! not!outstanding,! it! still! exists.! The! existing! correlation! between! air! pollution! and! the! other! two!variables!might!present!an!unexpected!direction!but!it!certainly!presents!a!weak!relationship!that!cannot!be!neglected.!!!Therefore,!one!can!say!that!the!first!objective!of!this!study,!which!was!to!add!to!the!empirical!evidence!existing!on! the!bilateral! relationships!between! the! three!concepts!of!air!pollution,!social!awareness!and!public!health,!can!be!partly!accomplished.!Indeed,!the!relationship!found!between!hospital!admissions!and!Twitter!comments!is!rightly!directed!and!though!it!is!weak,!it!still!exists.!!!From!the!CCF!results!that!involve!the!variable!hospital!admissions!it!seems!that!a!single!factor!cannot! fully! explain! a! concept! as! broad! as! hospital! admissions.! Nevertheless,! taking! into!account! that! the! lagged! correlations! always! showed! that! other! variables! led! hospital!admissions!and!that!instances!of!variables!in!all!of!the!three!fields!explored!produced!a!certain!relationship!between!themselves!and!this!variable!–!more!or!less!weak!and!rightly!or!wrongly!directed!–! it! seems!sensible! to!claim! that! these! results!will! serve!as!a!starting!point! to! the!development!of!the!forecasting!model.!!!

5.3+ Forecasting+model++!The! second! objective! of! this!monography!was! to! try! to! build! a! forecasting!model! for! daily!hospital! admissions! using! as! input! data! variables! related! to! air! pollution,! meteorological!conditions,! holidays! and!workdays,! Twitter! comments! containing! air! quality! and! symptomCrelated!keywords!and!hospital!admissions!themselves.!!!Although!single!relationships!between!hospital!admissions!and!instances!of!the!air!pollution!or!Twitter!comment!variables!are!not!mildly!strong,!as!the!CCF!results!show,!combining!the!input!variables!might!lead!to!an!accurate!forecasting!of!hospital!admissions.!Indeed,!in!this!section!the!aim! is! to!combine!all! input!variables!with! their!corresponding! lags! that!allow!to!make!a!better!forecasting!of!hospital!admissions.!!!The!seasonality!patterns!observed!in!hospital!admissions!suggest!that!there!might!be!some!autocorrelation!in!the!hospital!admissions!variable!and!therefore,!this!will!be!the!first!step!in!the!elaboration!of!the!forecasting!model.!!!

5.3.1! Hospital!admissions!autocorrelation!function!!!The!lagged!autocorrelation!analysis!results!are!shown!in!Figure!20!and!Table!20.!!

Results!!


!Figure&20&ACF&results&for&hospital&admissions&for&all&causes&&

!Autocorrelation+coefficient+ Lag+h%+(in+days)+

0,822731! C7!Table&20&Highest&autocorrelation&coefficient&and&corresponding&lag&for&hospital&admissions&

These!results!show!that!there!is!a!strong!correlation!between!hospital!admissions!in!the!time!t!and!hospital!admissions!in!t_7.!Indeed,!this!means!that!hospital!admissions!today!are!strongly!determined! by! hospital! admissions! a! week! earlierf! indeed,! the! day! of! the! week! seems! to!account! for!82%!of!hospital!admissions.!Undoubtedly,! the! forecasting!model! for! the!output!yt=hospital!admissions!in!t&must!include!as!input!yt_7.!!!

5.3.2! Model!training!and!testing!!!Based!on!these!results,!the!following!steps!will!be!to!introduce!other!variables!as!input!for!the!model!additionally!to!hospital!admissions!of!7!days!earlier!and!select!those!that!allow!a!more!accurate!output.!Indeed,!the!chosen!input!variables!and!their!corresponding!lags!are!shown!in!Table!21.!As!it!was!specified!in!the!description!of!the!techniques!used,!they!have!been!selected!according!to!their!correlation!to!the!total!hospital!admissions!obtained!from!the!CCF!analysis.!!!

Output+variable+yt+=+total+hospital+admissions+Input+variable+name+ Lag+(in+days)+total!admissions!lagging! C7!

SO2! C13!O3! C14!PM10! C9!PM2,5! C9!NO2! C14!T! C24!HR! C20!air! C15!

ambiental! C14!contaminación! C14!garganta! C15!respiración! C8!

sick! C2!

−20 −10 0 10 20

−0.4

−0.2

0.0

0.2

0.4

0.6

0.8

1.0

Lag

ACF

Total Admission VS Total Admission



tos! C8!Table&21&Input&variables&selected&for&the&forecasting&model&and&corresponding&lag&&

!!

Once!the!training!of!the!models!was!completed,!the!testing!leads!to!the!error!measurements!shown! in! Table! 22.! After! observing! these! results,! the! best! algorithm! is! the! SVM,! since! it!presents!the!least!error!in!all!three!measurements.!!!+ MLR+ SVM+ CART+ RF+ ANN+ GBM+ Bagged+CART+MAE+ 149,6523! 143,0234! 191,2768! 157,0166! 153,9616! 169,4191! 160,3384!RMSE+ 258,8015! 252,6663! 289,6049! 254,7269! 261,0873! 260,9216! 266,5853!RELE+ 0,118853! 0,118213! 0,157425! 0,124847! 0,121496! 0,134301! 0,128059!Table&22&Measure&of&MAE,&RMSE&and&RELE&for&the&different&supervised&learning&methods&applied&

5.3.3! Model!improvement!!The!fitted!SVM!model!is!represented!along!with!the!test!set!data!in!Figure!21.!The!obtained!model! fits! into! the!dataset!with!a! relative!error!of!11,82%.!Although! this!provides!as! it! is!a!useful!tool!for!public!health!administration,!its!results!can!be!improved.!In!order!to!do!so,!the!importance!of!the!input!variables!of!the!model!is!evaluated.!As!it!was!previously!explained,!the!RF!model!is!used!to!evaluate!this!importance.!Results!are!presented!in!Table!23.!!!

!Figure&21&Daily&hospital&admissions&according&to&the&real&dataset&and&to&the&SVM&prediction&model.&&

!Input*Variable* Importance*

Total!admissions!lagging! 9,005055692!

NO2! 0,904485429!

PM10! 0,474281243!

T! 0,45502817!

PM2.5! 0,332469096!

HR! 0,319111788!

SO2! 0,28526195!

O3! 0,267585415!

air! 0,174302893!

0 50 100 150 200

1000

1500

2000

samples

Daily

hos

pita

l adm

issio

ns

Real Predict

Results!!


tos! 0,171903771!

garganta! 0,161709414!

sick! 0,092588606!

ambiental! 0,079478177!

contaminación! 0,063329867!

respiración! 0,063147365!Table&23&Results&of&importance&analysis&based&on&random&forest&method&for&the&input&variables&of&the&model&&

!The!importance!of!the!input!variables!indicates!the!significance!of!including!them!in!the!model.!It!is!obvious!that!the!most!significant!input!variable!is!the!total!admissions!lagging!in!7!days,!which!has!an!importance!ten!times!bigger!than!its!successor.!However,!keeping!that!variable!as!the!only!input!variable!leads!to!an!MAE!of!over!1000,!which!rules!out!this!possibility.!Indeed,!the!next!steps!would!be!to!try!to!simplify!the!model!by!using!only!a!selection!of!the!current!input! variables! and! evaluating! the! respective! errors.! This! final! step! would! lead! to! the!elaboration!of!a!lowCerror!forecasting!model!of!the!hospital.!!From!the!analysis!of!the!importance!of!the!variables!in!the!current!model,!the!most!important!variable! is! admittedly! total! admissions! lagging! in! 7! days! followed! by! pollutants! and!meteorological!conditions.!Finally,!Twitter!comments!are!also!important!in!the!prediction!of!the!output!value!of!hospital!admissions,!especially!the!tweets!containing!“air”,!“tos”!and!“garganta”.!!!!

5.4+ Evaluation+of+impacts+and+responsibilities+of+the+project++!This!project!has!a!considerable!impact!on!society!and!the!environment!within!the!city!of!Madrid!since! it! is! directly! linked! to! public! policy! and! both! to! health! and! environmental! initiatives.!Furthermore,!it!was!conducted!within!ethical,!legal!and!social!responsibilities.!!!

5.4.1! Social!impacts!of!the!project!!!This!study!has!suggested!a!weak!correlation!between!social!awareness!and!both!air!quality!and!hospital!admissions.!This!suggests!that!society!is!still!not!completely!touched!by!the!air!pollution!crisisf!however,!individuals!are!somewhat!aware!of!this!situation!since!the!correlation!is!weak,!but!exists.!Indeed,!awareness!should!be!encouraged!and!evaluated!by!policy!makers!since,! as! it! has! been!mentioned! before,!many! of! the!measures! taken! against! air! pollution!require!individual!participation.!In!order!to!assess!the!expected!behavioural!change,!studies!like!this!one,!that!introduce!social!media!as!a!potential!tool!for!monitoring!social!trends,!should!be!carried!out!more!often.!!!In!the!descriptive!analysis!of!public!health,!data!used!comes!from!the!CMBD.!This!data!is!used!by!health!institutions!to!elaborate!reports!aggregating!information!yearly!or!based!on!common!diagnosis! like! flu!outbreaks.!Access!to!daily!hospital!admissions!data,! including! information!like!type!of!admission,!type!of!discharge!and!diagnosis!allows!for!a!more!precise!evaluation!of!public!health.!Indeed,!detailed!information!used!in!this!study!has!allowed!it!to!identify!seasonal!patterns!in!hospital!admissions.!Indeed,!hospital!care!in!the!urban!area!of!Madrid!seems!to!be!determined! by! social! habits! since! admissions! decrease! in! the! Summer! and! Christmas!holidays,!as!well!as!on!weekends.!!!Moreover,!the!importance!analysis!of!variables!in!the!forecasting!model!of!hospital!admissions!carried!out!in!this!study!reveals!that!there!is!an!impact!of!certain!pollutants!(namely!NO2,!PM2,5!and!PM10,!O3!and!SO2)! in!public!health.!Twitter!comments!also!have!an! impact!on!hospital!admissions,!since!twitter!input!variables!are!taken!into!account!in!the!forecasting!model.!This!positions!social!media!as!a!potential!tool!for!measuring!social!related!trends.!!!!



!Twitter! analysis! also! has! an! economic! impact! since! it! is! used! as! an! alternative! for!questionnaires!and!surveys!–!the!traditional!methods!in!sociological!studies,! that!are!timely!and!costly!expensive.!Furthermore,!it!makes!assessment!more!realistic!since!it!reduces!the!bias.!Indeed,!as!it!has!been!mentioned!before,!it!is!more!likely!to!be!biased!when!answering!a!question!than!when!having!the!initiative!to!publish!a!tweet.!Also,!with!310!million!active!users!per!month,!it!ensures!access!to!a!larger!portion!of!population!than!surveys.!!With!all!of!this!in!mind,!current!impacts!of!this!study!will!be!broadened!by!the!elaboration!of!a!scientific!publication!that!will!allow!for!divulgation!of!the!results!as!well!as!by!providing!public!institutions!with! the!main! findings!and!allowing! them! to!determine!whether!or!not! they!can!exploit! the!forecasting!model!of!hospital!admissions!to!their!profit.! Indeed,!when!requesting!the! information! available! from! public! institutions,! namely! the! Environmental! Information!System! and! General! Management! Direction! of! Sanitary! Assistance! of! the! Community! of!Madrid!expressed!their!interest!in!the!development!of!this!study.!!

5.4.2! Ethical,!legal!and!professional!responsibilities!!!In!current!times,!engineering!should!be!put!into!the!service!of!society.!Indeed,!the!development!of! studies! like! this! one,! that! combine!engineering!advances! in!diverse! fields,! including! the!development!of!new!technologies!and!new!ways!of!monitoring,!as!well!as!the!development!of!new!analytic!tools,!bring!an!evident!profit!to!the!individual!and!society.!Therefore,!this!line!of!work!does!respect!the!professional!responsibilities!of!an!engineer.!!!Legal! responsibilities!have!been!met!at!all! times,!namely!during! the!data!collection!phase.!Indeed,!all!health!related!information!was!kept!anonymous,!respecting!the!right!of!anonymity!of! patients! as! stated! in! the! Law! 41/2002,! regulating! patient’s! autonomy.! Moreover,! data!collected! was! either! publicly! available! for! download! as! a! result! of! the! Transparency! Law!19/2013!or!was!officially!requested!to!and!provided!by!Public!Health!Institutions.!!!Finally,! during! the!elaboration!of! this! study,!all! steps!have!been!carried!out!ethically.!Data!collection! and! its! aggregation! and! analysis! as! well! as! its! results! have! been! elaborated!honestly.!Moreover,!in!the!drawing!of!conclusions!and!elaboration!of!hypotheses,!dignity!and!respect!for!all!groups!and!institutions!has!been!ensured.!Definitely,!the!whole!elaboration!of!this!study!was!conducted!to!help!society!improve.!!!!!!!!!!!!!!!!!!!!!!

Results!!


!!!!!!!!!!



6! CONCLUSIONS!!

6.1+ Conclusions+of+the+project++!The!elaboration!of!this!study!responded!to!a!necessity!of!dealing!with!a!pollution!crisis!in!the!city!of!Madrid!combined!with!the!opportunity!of!heterogeneous!data!modelling!brought!by!new!technologies!and!techniques.!!!The!methodology! followed! was! consistent! with! that! used! in! similar! existing! studies! in! the!literature.!Data!selected!covered!as!broadly!as!possible!the!issue!at!hand.!Indeed,!air!pollution!was!measured!through!hourly!concentration!of!12!pollutants!in!24!stations!covering!a!604!km2!area,!combined!with!another!12!meteorological!variables!from!26!stations!in!that!same!area.!Public!health!was!measured!accessing! to!daily!hospital!admissions!of! the! totality!of!public!hospitals! in! the! city! of!Madrid,!which! add! up! to! 15.!Moreover,! the! data! from!public! health!included!specific!datasets!all!of!the!diagnosis!that!are!supported!by!the!existing!empirical!body!of!work!as!being!linked!to!air!pollution.!Lastly,!Twitter!comments!were!scraped!for!more!than!22!keywords!related!not!only!to!air!quality!issues!but!also!to!its!health!impacts.!From!these!initial! keywords,! only! 16! produced! enough! volume! of! tweets! and! only! 7! of! those! were!introduced!in!the!forecasting!model.!It!can!be!said!that!data!collection!was!quite!exhaustive.!!!From!this!heterogeneous!data,!empirical!results!of!applying!the!CCF!analysis!do!not!support!strong! bilateral! relationships! between! air! pollution,! social! awareness! and! health! impacts.!However,!the!existence!of!these!relationships!in!weak!terms!cannot!be!denied.!In!view!of!this,!it!can!be!concluded!that!the!first!objective!has!been!partly!accomplished!by!finding!a!certain!degree!of!relationship!between!Twitter!comments!and!hospital!admissions!that!is!consistent!with! statement! (iii)! the! greater! the! health! impacts! of! air! pollution,! the! greater! its! social!awareness.!The!other!statements!cannot!be!supported!since!the!direction!of!the!relationships!seems!to!be!opposite!to!what!was!established!in!the!objectives.!However,!despite!of!being!unexpectedly!directed,!these!relationships!still!exist!and!can!be!used!for!the!purpose!of!the!second!objective!of!this!monography.!Furthermore,!CCF!results!show!that!hospital!admissions!are!lagging!behind!all!other!variables.!!!The!autocorrelation!analysis!of!hospital!admissions!data!reveals!that!this!autocorrelation!is!at!its!strongest!(with!a!Pearson!coefficient!of!0,8227)!when!the!lag!between!variable!instances!is!7! days.! This! means! that! there! is! a! strong! influence! of! the! day! of! the! week! in! hospital!admissions!but,! this! influence!is!able!to!explain!82%!of!hospital!admissions.!There! is!still!a!20%! that! can! be! explained! by! other! variables.! Indeed,! the! importance! analysis! of! input!variables!in!the!model!shows!that!pollutants!including!NO2,!PM2,5!and!PM10,!O3!and!SO2,!along!with!variables!representing!daily!volume!of!tweets!with!related!keywords!are!able!to!explain!the!rest!of!hospital!admissions.!!!The! positive! relationship! established! by! the! CCF! results! between! Twitter! comments! and!hospital!admissions,!combined!with!the!prevalence!of!tweets!as!input!variables!for!forecasting!hospital! admissions! suggest! that! social! media! is! undoubtedly! a! tool! for! measuring! and!understanding!social!trends!well!beyond!the!assessment!of!opinion!but!reaching!prediction!of!health!care!needs.!!!Hence,!combining!the!results!of!the!CCF!analysis!and!data!mining!techniques!has!allowed!to!build! a! model! that! can! actually! forecast! with! a! lag! of! two! days! the! number! of! hospital!admissions!in!the!public!hospitals!of!the!city!of!Madrid!with!a!precision!of!88%.!This!means!that!the!second!objective,!that!seemed!at!first!quite!ambitious,!has!been!accomplished!in!a!quite!satisfactory!manner.!!!

Conclusions!!


6.2+ Limitations+and+proposition+of+further+research++!The!weak!correlations! found! in! the! first!part!of! this!study!can!be!partly!explained!by!some!limitations! the! model! was! faced! with.! First! of! all,! correlations! were! made! between! single!pollutants!and!total!number!of!hospital!admissions.!Indeed,!this!comes!in!useful!for!the!final!target!of!this!study,!which!was!the!building!of!the!forecasting!model!for!hospital!admissions,!but!in!order!to!generate!empirical!evidence!of!the!relationship!between!pollution!and!hospital!admissions,!this!might!not!have!been!the!best!approach.!Indeed,!hospital!admissions!depend!on!many!more!aspects.!Correlating!an!air!quality!index!that!combines!all!pollutants!to!specific!diagnosis!might!be!a!better!approach,!as!it!had!been!done!in!other!studies.!!!The! built! model! is! a! powerful,! time! and! cost! efficient! tool! that! will! surely! benefit! the!management!of!public!health!resources.!Nevertheless,!it!could!be!interesting!to!also!take!into!account!private!hospital!facilities!in!the!city,!since!they!also!reflect!the!current!situation!of!public!health.! Indeed,! the!private!health! facilities! in!general!medicine!can!bed!2028!patients,!and!though!this!is!not!close!to!the!more!than!9600!beds!available!in!public!hospitals,!it!mustn’t!be!neglected.!Access!to!this!information!will!however!be!a!harder!task.!!!Indeed,!from!the!currently!built!model,!several!further!research!lines!of!work!can!be!extracted.!It!would!be!interesting!to!model!hospital!overnight!stays!aggregating!data!by!diagnosis!and!also!by!time!in!order!to!obtain!a!better!assessment!of!population’s!health,! identifying!public!health!threats!and!helping!make!better!informed!clinical!decisions.!!!Furthermore,!it!could!be!interesting!to!study!individual!hospitals!since,!as!it!was!suggested!by!existing! studies! in! the! literature,! there! is! a! difference! between! neighbourhoods! in! what!concerns!air!pollution.!However,!this!research!would!need!a!more!spatially!precise!pollution!exposure!assessment,!since!isolating!measures!from!single!fixed!stations!in!the!surroundings!of!hospitals!might!not!be!possible!due!to!the!lack!of!these!stations!on!such!locations!and!might!lead!to!overCfitting!problems.!!!More!directed!to!the!exploitation!of!social!media,!this!work!could!be!further!completed!by!the!study!of!the!social!crisis!detected!through!the!assessment!of!volume!of!daily!tweets.!Indeed,!abnormally!high!peaks!were!reached!in!several!dates!for!different!keywords.!!An!identification!and! analysis! of! the! real! events! could! lead! to! the! labelling! of! social! concerns! and! an!understanding!of!social!behaviour!patterns.!!!Furthermore,!the!use!of!sentiment!analysis,!often!referred!to!as!opinion!mining,!could!be!used!as!an!evaluation!tool!for!hospital!quality,!adapting!the!keywords!to!be!crawled.!Moreover,!the!monitoring!of!social!awareness!could!be!carried!out!by!the!elaboration!of!more!frequent!studies!of!this!sort.!!!!!!!!!!!



7! PLANNING!OVER!TIME!OF!THE!PROJECT!!!!The! elaboration! of! this! project! can! be! divided! into! 6! parts,! since! the! assignation! and!presentation! of! the! project! to! its! participants! until! its! formal! presentation! to! the! jury.! The!planning!of! the!Project! is! visible! in! the!Work!Breakdown!Structure! (WBS)!of! the!Project! is!presented!in!Figure!22.!In!Table!24,!each!work!package!is!associated!with!the!estimated!time!dedicated!to!it.!The!total!time!spent!in!the!elaboration!of!the!Project!is!therefore!estimated!in!360!hours,!corresponding!to!a!Bachelor!Project!of!12!ECTS.!Also,!a!precedence!diagram!in!GANTT!view!of!the!Project!elaboration!is!presented!in!Figures!23!and!24.!!!In!the!following!sections,!the!elements!of!the!WBS!Level!2!will!be!briefly!described.!!!

7.1+ Project+management++!The!presentation!of!this!project!to!its!participants!wass!held!on!the!24th!February!2016.!This!project!was!proposed!by!the!Projects!Department!as!a!collaborative!project!between!one!of!their! scholars! and! a! bachelor! in! the! Escuela! Técnica! Superior! de! Ingenieros! Industriales!(ETSII).!On!this!meeting,! the!project!was!presented!to! the!bachelor!student,!along!with! the!definition!of!the!project’s!objectives.!Since!the!project!was!working!against!the!clock,!on!this!meeting!it!was!established!that!the!data!collection!should!start!as!soon!as!possible.!!The!project!evolution! is!monitored!by! the!Tutor.!This!monitoring! includes!evaluation!of! the!written! description! project,! suggestion! of! changes! and! update! controls.! Furthermore,! this!monitoring!includes!the!evaluation!of!the!results!obtained,!as!well!as!suggestion!of!changes!in!case!of!unsatisfactory!results.!This!phase!is!present!throughout!the!whole!project.!!!

7.2+ Data+collection++!Data!collection!starts!right!after!the!definition!of!objectives,!on!the!25th!of!February.!Some!data!was!already!available!for!download,!like!the!pollution!data!from!the!monitoring!stations.!Other!data!had!to!be!requested!and!then!was!downloaded:!this!is!the!case!of!the!public!health!data!and!meteorological!data.!Finally,!in!order!to!automatically!collect!the!publicly!available!Twitter!data,!a!scraper!had!to!be!put! into!place!and!then!data!was!obtained.!This!phase!was!quite!long! and! slow,! since! requests! had! to! be!made! officially! and! several! times! until! data! was!provided.!Moreover,!data!size!was!extremely!big!since!the!biggest!data!scale!was!daily!data!for!a!period!of!two!years.!After!the!data!collection,!the!data!format!had!to!be!unified.!!!

7.3+ Education+on+the+problem+++!Once!the!data!was!obtained!and!shared!to!all!the!participants!of!the!project,!it!was!necessary!to! obtain! formation! on! the! problem.! The! bachelor! student! had! to! get! information! on! the!legislative! background! concerning! the! subject! at! hand! as! well! as! on! the! previous! studies!existing! in! the! literature.! This! phase! consisted! on! a! lot! of! research! on! the! open! literature!through!the!Google!Scholar!website.!!!!

7.4+ Resolution+of+the+problem++!Once!the!data!was!aggregated!and!ready!to!be!analysed!together,!and!based!on!data!mining!techniques,!suitable!methods!were!established!in!order!to!fulfil!the!objectives!of!the!project.!Data!was!managed!with!the!statistical!software!RCProject!and!results!were!obtained.!In!this!phase! there!was!a! feedback! loop!between!results!and!chosen! techniques,!having! to!adopt!more!sophisticated!techniques!when!results!were!not!satisfactory.!!

Planning!over!time!of!the!project!!


!7.5+ Writing+of+the+Research+Project+Description++

!This!phase!of! the!project! and! the! formation!on! the!problem!started! simultaneously.! In! this!phase,! each! section!was! developed! similarly.! An! initial! rough! draft! of! the!main! ideas!was!submitted!to!the!Project!Supervisor,!whose!recommendations!were!used!to!readapt!the!draft.!Then,! the! full! length! content! was! created! and! submitted! again! to! the! Supervisor.! Later,!following!recommendations,!modifications!were!made!until!it!was!approved!by!the!Supervisor.!!!

7.6+ Elaboration+of+the+oral+presentation+to+the+jury+!The!last!step!in!the!elaboration!of!the!Project!is!its!presentation!to!the!Jury!in!September!2016.!In!this!phase,!it!is!necessary!to!select!the!most!relevant!information!in!order!to!establish!the!content!of!the!oral!presentation.!Following!that,!the!slides!must!be!created!and!the!presentation!must!be!rehearsed.!Finally,!the!project!will!end!on!the!date!were!the!Project!is!presented!to!the!jury,!which!will!take!place!in!one!of!the!following!dates:!12th,!13th!or!14th!of!September!2016.!!!WBS!Level!

WBS!Code!!

WBS!Name! Estimated!Duration!(h)!

1! 1! Estimators!of!social!awareness!concerning!pollution!crisis! in! the!city!of!Madrid!

360!

2+ 1.1+ Project+management+ 31+3! 1.1.1! Definition!of!Project!Scope!and!objectives!! 1!3! 1.1.2! Project!monitoring!and!progress!control!!! 25!3! 1.1.2! Final!Project!Description!Revision!! 5!2+ 1.2+ Data+Management++ 95+3! 1.2.1! Data!collection!and!format!management!! 25!4! 1.2.1.1! Download!of!pollution!data! 1!4! 1.2.1.2! Request!of!meteorological!data!and!download! 2!4! 1.2.1.3! Request!and!download!of!hospital!admissions!data! 7!4! 1.2.1.4! Twitter!Scraper!development!and!data!crawling!! 15!3! 1.2.2! Data!aggregation!! 70!2+ 1.3+ Education+on+the+problem++ 100+3! 1.3.1! Formation!on!the!applicable!law!in!force! 40!3! 1.3.2! Research!of!the!literature!for!previous!studies!! 60!2+ 1.4+ Resolution+of+the+problem++ 65+3! 1.4.1! Selection!of!the!methodology!! 5!3! 1.4.2! Results! 60!2+ 1.5+ Project+Monography+Preparation+++ 53+3! 1.5.1! Writing!of!the!Introduction!and!State!of!the!Art! 18!3! 1.5.2! Writing!of!the!Objectives!and!Methodology!! 15!3! 1.5.3! Writing!of!the!results’!analysis!and!conclusions! 20!3! 1.5.4! Project!Description!Hand!in!! 0!2+ 1.6+ Preparation+of+the+Oral+Presentation++ 16+3! 1.6.1! Selection!and!elaboration!of!the!presentation!content! 10!3! 1.6.2! Elaboration!of!the!presentation!slides! 5!3! 1.6.3! Presentation!to!the!jury!! 1!

Table&24&Estimation&of&duration&for&each&work&package&in&the&WBS&

!!!!!!!



!!!!!!!

!Figure&22&WBS&of&the&Project&&

!!!!!!!!

1!Estimators!of!social!awareness!concerning!

pollution!crisis!in!the!city!of!Madrid!

1.1!Project!management!

1.1.1!Definition!of!project!scope!and!

objectives

1.1.2!Project!monitoring!and!progress!control!

1.1.3!Final!Project!Description!Revision

1.2!Data!management!

1.2.1!Data!collection!and!format!management!

1.2.1.1Download!of!pollution!data!

1.2.1.2!Request!of!meteorological!data!

and!download!

1.2.1.3Request!and!download!of!hospital!

admissions!data

1.2.1.4!Twitter!Scraper!development!and!data!crawling

1.2.2!data!aggregation!

1.3!Education!on!the!problem!!!!!!!!!!!!!!!!!!!!

1.3.1!Formation!on!the!applicable!law!in!

force

1.3.2!Research!of!the!literature!for!

previous!studies

1.4!Resolution!of!the!problem!

1.4.1!Selection!of!the!methodology

1.4.2!Results

1.5!Writing!of!the!Project!Description!

1.5.1!Writing!of!the!Introduction!and!State!of!the!Art

1.5.2!Writing!of!the!objectives!and!methodology!

1.5.3!Writing!of!the!results' analysis!and!

conclusions

1.5.4!Project!Description!Hand!in!

1.6!Preparation!of!Oral!Presentation!

1.6.1!Selection!and!elaboration!of!the!

presentation!content!

1.6.2!Elaboration!of!the!presentation!

slides

1.6.3!Presentation!to!the!jury!



!!!!!!!!!!!!!!!!!!

!!Figure&23&Precedence&diagram&in&GANTT&view&&of&Level&2&WBS&activities&&

!!!!!!!!!!!!!!!



!

!

!Figure&24&Precedence&diagram&in&GANTT&view&of&all&work&packages&&

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!

8! BUDGET!OF!THE!PROJECT!!!!In!order!to!elaborate!the!budget!of!the!project!at!hand,!the!same!work!units!from!the!WBS!will!be!used.!!The!work!units!considered!will!not!be!the!lowest!level!of!decomposition!in!the!WBS,!but!the!second!level,!for!practical!reasons.!!!

8.1+ Unit+price+tables++!

8.1.1! Unit!price!table!of!workforce!!!Unit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Designation!

!Price!(euros)!

!H!

!Intern!at!the!Project’s!Department!!

!11!

H!H!

Bachelor!Student!!Tutor!!

0!27!

!!

8.1.2! Unit!price!table!of!material!items!!!IT!materials!are!included!in!this!category.!!!Unit! Designation!

!Price!(euros)!

!H!

!Computer!!

!0,5!

year! RCStudio!license! 904,5!student!/year!

Microsoft!Office!license! 19,75!!

!!

8.1.3! Unit!price!table!of!auxiliary!items!!!Unit! Designation!

!Price!(euros)!

!journey!

!Transport!

!1,5!

student! Subscription!to!scientific!magazines! 12,5!variable/H! AEMET!information!! 1,01!request! AEMET!management!expenses! 14!

!!!!!!!!

Budget!!


8.2+ Unit+price+of+work+units++!Nº! Designation! Amount!(euros)!!!1.1!

!1!Project!Management!Definition!of!Project!Scope!and!Objectives!

!!

38!1.2! Project!monitoring!and!progress!control! 675!1.3! Final!Project!Revision!! 5!! !

2!Data!Management!!!

2.1! Request!of!Meteorological!data.!Download! 192,92!2.2! Request!Hospital!Admisions!Data! 9!2.3!! Twitter!Scraper!development!and!data!crawling! 252,5!2.4! Data!aggregation! 812,3!! !

3!Education!on!the!problem!!!

3.1! Access!to!scientific!publications! 12,5!3.2!! Computer! 50!! !

4!Problem!resolution!!!

4.1! Methodology!selection!! 55!4.2! Results! 36,2!! ! !! !

5!Project!Monography!Preparation!!!

5.1! Computer!! 46,25!! ! !! !

6!Oral!Presentation!!

6.1! Computer! 7,5!!

8.3+ Unit+prices+of+work+units’+breakdown+!Nº! Designation! Amount!! ! ! ! Partial!

(euros)!Total!(euros)!

+ 1+Project+Management++ + 848+1.1! Definition!of!Project!Scope!and!Objectives!! ! !! 1!H! Tutor! 27! 27! !! 1!H! Intern!! 11! 11! !! ! ! ! ! 38!1.2! Project!monitoring!and!progress!control!! ! !! 25!H! Tutor! 27! 675! !! ! ! ! ! 675!1.3! Final!Project!Description!Revision!! ! !! 5!H! Tutor! 27! 135! !! ! ! ! ! 135!! ! ! ! ! !+ 2+Data+Management+ + 1257,72+2.1! Request!of!meteorological!data!and!download!! ! !! 144!var!! AEMET!variable! 1,01! 145,44! !! 1! management! 14! 14! !! ! V.A.T! 0,21! 33,48! !! ! ! ! ! 192,92!



2.2! Request!and!download!of!Hospital!admissions!data!!! ! !! 6!journeys! Transport! 1,5! 9! !! ! ! ! ! 9!2.3! Twitter!Scraper!!development!and!data!crawling! ! !! 5!H! Tutor! 27! 135! !! 10!H!! Intern! 11! 110! !! 15!H! Computer!! 0,5! 7,5! !! ! ! ! ! 252,5!2.4!! Data!aggregation!! ! !! 70!H! Intern! 11! 770! !! 70!H! Computer!! 0,5! 35! !! 0,008!years!! RCStudio!! 904,5! 7,3! !! ! ! ! ! 812,3!! ! ! ! ! !+ 3+Education+on+the+problem++ + 62,5+3.1! Access!to!scientific!publications!! ! !! 1!student! Subscription! to!

scientific!magazines!!12,5! 12,5! !

! ! ! ! ! 12,5!3.2! Computer!! ! !! 100!H! Computer! 0,5! 50! !! ! ! ! ! 50!! ! ! ! ! !+ 4+Resolution+of+the+Problem++ + 91,2+4.1!! Methodology!Selection!! ! !! 5!H! Intern! 11! 55! !! ! ! ! ! 55!4.2! Results! ! !! 0,0068!years! RCStudio! 904,5! 6,2! !! 60!H! Computer! 0,5! 30! !! ! ! ! ! 36,2!+ 5+Project+Monography+Preparation+++ + 46,25+5.1!! Computer! ! !! 53!H! Computer! 0,5!! 26,5! !! 1!student/year! Microsoft! Office!

license!19,75! 19,75! !

! ! ! ! ! 46,25!! ! ! ! ! !+ 6+Oral+Presentation++ + 7,5+6.1! Computer!! ! !! 15!H! Computer!! 0,5! 7,5! !! 5!H! Microsoft! Office!

license!!0! 0! !

! ! ! ! ! 7,5!!! ! ! ! ! !!!!!!!!!!

Budget!!


8.4+ Budget++!Chapter+ + Amount+Chapter!1! Project!Management! 848!Chapter!2! Data!Management! 1257,72!Chapter!3! Education!on!the!Problem! 62,5!Chapter!4! Resolution!of!the!Problem! 91,2!Chapter!5! Project!Monography!Preparation!! 46,25!Chapter!6! Oral!Presentation!! 7,5!Budget+of+material+execution++ 2313,17+13%!General!Costs! 300,7121!6%!Industry!Profit!! 138,7902!Sum! ! 2752,6723!21%!V.A.T! ! 578,06!Contracted+Operation+Budget+ 3330,7329+!!!



!

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