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Transcript of PRIMARY SCHOOLS ENVIRONMENTS - Universidade do...
PTDC/DTP-SAP/1522/2012
INDOOR BIOLOGICAL AGENTS: EVALUATION OF
PRIMARY SCHOOLS ENVIRONMENTS
Lívia Vanessa Ferreira de AguiarWork under the supervision of:
- Professor João Paulo Teixeira
- Professor Celina Pinto Leão18th February 2016
Master Thesis for MSc Degree in Human Engineering
Guimarães, Portugal
INTRODUCTION
8th most importantrisk factor for thedevelopment ofdisease
4.3 million deathsannualy
WHOMain 5 environmental risksto public health
Indoor levels ofpollutants can be 2 to 5 times higherthan outdoor levels
US EPA
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INTRODUCTION
The results of this study are part of ARIA Project, performed between 2013 and 2015.
Explore associations between various exposures that children experience in their indoor environments (specifically their homes and primary schools).
Investigate the associated respiratory and allergic related health effects in 1600 children.
The targeted health issues were allergy, asthma and respiratory symptoms.
PROJECT MAIN OBJECTIVES
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STUDY RELEVANCE
Over
crowding
Highincidence ofinfectiousdiseases
Reducedbudgets SCHOOLS
Inadequatemaintenance of school
buildings
Although home environment has been the focus of research studies…
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Susceptible group due to their particularly vulnerability to the development ofrespiratory diseases.
Time they spend inside classrooms
Indoor Air Qualitystudies
STUDY RELEVANCE
Impact on child’s exposure to pollutants
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OBJECTIVES
To evaluate children’s exposure to indoor air biologicalpollutants in primary schools of Porto, Portugal
To evaluate children’s exposure to indoor air biologicalpollutants in primary schools of Porto, Portugal
To assessand quantifybacteria, fungiand endotoxinsconcentrations, in 20 primary
schools, and to compare theattained resultswith national/ internationalguidelines
To assess theimpact ofoutdoor
bacteria andfungi
concentrationsin indoor air
To identifythe main
fungi genera/ speciespresent
To investigate
the influence ofCO2, T and RH concerning the
biologicalpollutants
concentrations
To determine if the
concentrationsof bacteria, fungi andendotoxins
varies according witheach other’s
concentrations
To investigateif primaryschools’
buildings/ classroom
characteristicsand occupants
activitiesinterfere with
indoor airbiological
contaminationlevels
To suggestintervention
and/orimprovementmeasures for a better IAQ in primaryschools
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METHODOLOGY
Cross-sectional study
20 schools, with the highest number of students and considered representative of the
building stock were invited to participate in this study and all of them agreed.
In each school, four classrooms of 3rd and/or 4th grades were selected, among classrooms with
similar conditions and considered to be representative of the school building.
Classrooms should have high density of occupation and full weekly occupation time by the
same class.
A total of 71 classrooms were assessed,
comprising a universe of 1523 students attending daily classes.Figure 1 - Geographical distribution of the selected
20 public primary schools.
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METHODOLOGY
Two heating season periods:
January to April 2014 - 10 schools, 35 classrooms
October 2014 to January 2015 - 10 schools, 36 classrooms
Normal activities and under representative conditions of occupancy of the classrooms
CROSS-SECTIONAL STUDY OF CHILDREN’S INDOOR AIR EXPOSURE
Enclosedenvironments
Studied parameters:
Building and classroom characteristics
standardized validated checklist [SINPHONIE]
Biological parameters
total bacteria count and fungi count and
identification
endotoxin concentration
Chemical parameters Carbon Dioxide [CO2]
Physical parameters Temperature [T] and Relative Humidity [RH]
Figure 2 - TSI 7545 IAQ-CALC
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TSABacteria
MEAFungi
TSA
MEA
MAS100, 250 Liters of air volume, 100 Liters per minute (L/min) rate
Duplicates
Four field blanks, two sterility blanks, one positive and one negative control per
culture medium, per day
Outdoor samples were also collected in each campaign, for comparison to
the indoor measurements
TSA
MEA
37±1ºC
25±3ºC
48±3 h
72±3 h
Fungal colonies identification: phenotypic characteristics and standard mycological procedures based on their
micro and macro-morphological characteristics
Quantification: naked eye count
METHODOLOGY
RESULTS: CFU/M3
BACTERIA & FUNGI ASSESSMENT
Figure 3 - Microbiological air impactor (Merck Air Sampler, MAS-100).
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SAMPLING
Portable high flow pump [2 L/min flow]
Button aerosol sampler with a 25 mm glass microfibre filter [GFA]
4 hour sampling
All materials used for sampling were treated at 180ºC for at least 4 hours prior to sampling.
Samples were kept frozen at -20ºC until analysis.
METHODOLOGY
RESULTS: EU/M3
ENDOTOXINS ASSESSMENT
ANALYSIS
EXTRACTION
Sample filters were eluted in 5 mL extraction solution.
Rocked vigorously for 1h at room temperature on a
horizontal shaker.
After 10 minutes of centrifugation at 1000 g, total
supernatant per sample was collected and analyzed.
QUANTIFICATION
LAL Kinetic-QCLTM [Lonza®] following manufacturer’s
guidelines.
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments of primary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? And what about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations foundindoors?
Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schoolsexceed the respective national and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments ofprimary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? Andwhat about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations foundindoors?
Are indoor biological concentrations affected by building and/or classroomscharacteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?12
RESULTS
Bacteria levels 2 to 9 times higher than the established limit value
40 x
66 x
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RESULTS
Figure 4 - Mean endotoxins concentrations (EU/m3) by primary school
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels atschools?
What are the predominant fungi genera/species identified in indoor environments ofprimary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? And what about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESULTS
Figure 5 - Mean indoor and outdoor bacteria and fungi concentrations (CFU/m3)
Significant differencesfound between indoorand outdoor bacteria
as well as fungiconcentrations
For bacteria, I/O ratios higher than 1 were observed in all schools.
For fungi, 5 schools had I/O ratios below than 1.
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments of primary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? And what about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESULTS
Penicillium sp.
Cladosporium sp.
INDOOROUTDOOR
Figure 6 - Mean percentage of fungi genera/species identified indoors.
18Lívia AguiarAspergillus fumigatus
RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments ofprimary schools?
Indoor air biological parameters are influenced by T or RH of theindoor environment? And what about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESULTS
Figure 8 - Indoor concentrations of Bacteria and CO2, by SchoolFigure 9 - Indoor concentrations of Fungi and RH levels, by School
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments of primary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? Andwhat about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESULTS
Figure 10 - Indoor concentrations of Bacteria and Fungi, by School
Figure 11 - Indoor concentrations of Bacteria and Endotoxins, by School
Figure 12 - Indoor concentrations of Fungi and Endotoxins, by School
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments of primary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? Andwhat about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/orclassrooms characteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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RESULTS
Endotoxins concentrations were
higher in buildings with:
single walls
without roof leaking
Endotoxins concentrations & Year of
building refurbishment:
the more recently the intervention was
made, the higher were concentrations of
endotoxins in indoor air.
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RESULTS
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RESEARCH QUESTIONS
Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?
Is outdoor air the major influence on indoor air biological levels at schools?
What are the predominant fungi genera/species identified in indoor environments of primary schools?
Indoor air biological parameters are influenced by T or RH of the indoor environment? Andwhat about CO2?
Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?
Are indoor biological concentrations affected by building and/or classroomscharacteristics, including occupancy?
How can we improve IAQ of primary schools, regarding indoor biological parameters?
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IMPROVEMENT MEASURES
Strategies of source control
Carefully studythe location of
future buildings andits relationshipwith outdoor environment
Proper design and
construction ofschool
buildings andselection of
clean materials
Proper level ofcontinuosthermal
insulation ofthe building
avoidingcondensationsand dampness
indoors
Decoupling ofheating/ cooling
functions fromthe ventilation
system
Definition andenforcement of
limits for maximumpermittedoccupationdensities in classrooms; definition ofclasses and
breaks durations; establish
routines ofcleaning andmaintenanceprocedures
Periodical monitoring of
IAQ and healthparameters in
schools
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IMPROVEMENT MEASURES
VentilationMeasures
Portuguese guidelines suggests a ventilation rate of 24 m3/(hour.person)for classrooms
Admission of outside air should be explored, unless confirmed outdoorsources or pollution are located nearby the school
Naturally ventilate classrooms through windows opening before the schoolday starts, during each classroom break and also after cleaning procedures
Implementation of tilting windows and the introduction of ventilation grillsin windows frames
Implementation of mechanical system when natural ventilation is notsufficient to reach the desired ventilation rate, preferably with intake of freshair, and attention must be paid to its regular inspection and maintenance
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CONCLUSIONS
MAIN FINDINGS:
Mean indoor bacteria concentrations were above national limit values
in all of the evaluated Porto primary schools, from 2 to 9 times higher.
High numberof occupants
Lack ofventilation
Active behavioralpattern ofchildren
School buildingand classroomscharacteristics
Endotoxins concentrations were below the recommended value of 50 EU/m3 in all primary schools
evaluated.
Fungi indoor levels were above the reference value in 75% of the schools and overall indoors levels registered
a 3-fold increase comparing with outdoor values.
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CONCLUSIONS
MAIN FINDINGS:
Overall I/O ratios of 9 and 3 for bacteria and fungi concentrations, respectively,
demonstrated that indoor sources are the major influence on biological levels at schools.
Penicillium sp. and Cladosporium sp. were the prevalent fungi species found indoors and outdoors of
primary schools. Both genera are considered common in indoor environments according with national legislation
and several studies available in current literature.
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CONCLUSIONS
MAIN FINDINGS:
Bacteria and endotoxins concentrations were higher with higher levels of RH and CO2.
Fungi concentrations did not fluctuate with T, RH or CO2 …
But did positively relate with bacteria concentrations: higher values of fungi
corresponded to higher levels of bacteria.
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CONCLUSIONS
MAIN FINDINGS:
Contrarily to what was expected, bacteria and endotoxins concentrations
showed no relation between them.
Endotoxins were the studied biological parameter that showed to be more
affected by school building and classrooms characteristics.
To improve IAQ of primary schools, strategies of source control should be adopted as these are the most
consistent and efficient for the prevention of adverse health consequences to children in schools, like the
development and aggravation of asthma, allergies and respiratory symptoms.
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FURTHER DEVELOPMENTS
Assess indoor environment in a larger sample of primary schools, in an integrated IAQ audit
Perform IAQ audits in the same classrooms of primary schools along all school year
Extend this IAQ audit to the indoor environment of children’s homes
Perform endotoxin assessment in rural and urban environments, with and without farming activities
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