Air Pollution

Air Pollution

Air Pollution

Presented byDr. B. Victor

About the presenterAbout the presenter Dr.B.Victor is a highly experienced

postgraduate biology teacher, recently retired from the reputed educational institution St. Xavier’ s College, Palayamkottai, India-627001.

He was the dean of sciences and assistant controller of examinations.

He has more than 32 years of teaching and research experience

He has taught a diversity of courses ranging from Send your comments to : pre- university to post graduate classes.

[email protected]

Presentation outlinePresentation outline

What is pollution?Kinds of pollution sourcesSources of air pollutantsKinds of air pollutantsEffects of air pollutantsGreen house effect and global

warmingAcid rain Indoor air pollutionControl measures

Gaia hypothesis Gaia hypothesis

The Earth is like a living organism, which itself engaged in a self regulation to support its own "survival"

"The chemical and physical condition of the surface of the Earth, of the atmosphere, and of the oceans has been made fit and is actively made fit and comfortable by the presence of life itself."

This is what earth looks likeThis is what earth looks like

Pollution - Definition: Pollution - Definition:

Any addition to air, water, soil etc that threatens the health, survival of humans or other living organisms

1. Natural - volcanic eruption 2. Anthropogenic - burning

coal

Types of Sources:Types of Sources:

1. Point source - single, identifiable source e.g. smokestack, drainpipe etc

2. Non-point source - dispersed source, e.g. runoff from pesticides, fertilizers

Non-point sourcesNon-point sources

Point sourcePoint source

What are the key environmental problemsWhat are the key environmental problems

A. Population growth B. Resource use without preventing pollution and reducing waste C. Degrading habitats and reduction of biodiversity D. Poverty E. Failure of govt to encourage earth sustaining economic development

The Paul Ehrlich EquationThe Paul Ehrlich Equation

I = P * A * T = Eye PAT Impact = Population x Affluence x

Technology. where:I is the impact on the environment resulting from consumptionP is the population numberA is the consumption per capita (affluence)T is the technology factor

The AtmosphereThe Atmosphere

Gases that envelop the Earth and are held here by gravity regulates temperature.

Major gases: 78.08% nitrogen 20.95% oxygen 0.93% argon 0.03% carbon dioxide trace amounts of water vapor (close to

surface) 0.01% by volume near poles to 5% near equator and many others hydrogen, neon, helium, krypton, ozone and methane

Composition of AirComposition of Air

Layers of the atmosphere




Troposphere : 75% of mass of air; 17 km thick A turbulent layer of rising and falling air currents.

Stratosphere : extends up to 50 km above the Earth's surface. Less dense, contains nearly 99% of remaining atm.; similar composition. Ozone has a higher volume here (1000 x troposphere), water vapor has a lower volume (1/1000). Calm air. Little vertical mixing.

Mesosphere : 50-90 km Thermosphere : 90-110 km

Stratospheric ozone layer, O3Stratospheric ozone layer, O3

. Formed by a natural process. Produced by O2 interacting with

lightning and UV radiation. Absorbs most of the shorter

wavelengths - UV radiation which is damaging to living things causing cancer, sunburn, cataracts etc.

allows life to live on earth ozone depletion - a reduction of the

ozone layer.

What are the major sources and types of air

pollution?

What are the major sources and types of air

pollution?

Air pollution :DefinitionAir pollution :Definition

the presence of one or more chemicals in the atmosphere in sufficient quantities and duration to cause harm to humans etc.

Air PollutionAir PollutionAir pollution results from human

activities such as burning fossil fuels (oil, coal, and gasoline) to create electricity and power automobiles, and manufacture industrial products such as chemicals and plastic.

The air Pollutants are particulates, HC, CO2, CO, NO, NO2, SO3 -- source may be industrial, autos, etc.

Air pollutionAir pollution

The increased carbon dioxide in the atmosphere contributes to the warming of the global climate, the so-called "greenhouse effect."

The increased Chlorofluoro-carbons in the atmosphere has been depleting stratospheric ozone.

Sources of Air pollutionSources of Air pollution

Natural: volcanoes, fumaroles and hot springs decay from marshes, bogs increase ozone due to thunderstorms,

fires.

Man made (most severe for human health):Man made (most severe for human health):

Stationary sources - those that are fixed in location.

point sources e.g. smoke stacks, 14% air pollution from plants generating electricity;

fugitive sources e.g. construction sites, exposed areas;

area sources e.g. dense urban community or agricultural area

Mobile sources - those that move while polluting, e.g. trucks, cars, busses etc. 60% of air pollution from motor vehicles. 80-88% in major cities!

What are the main categories of air

pollutants?

What are the main categories of air

pollutants?

The main categories of air pollutantsThe main categories of air pollutants

Primary: those emitted directly into the air; e.g. sulfur dioxide (SO2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2)

Secondary: those that form as a result of a chemical reaction of the primary pollutant with a natural component of the environment.; e.g. some ozone, sulfuric and nitric acids.

Types of pollutantsTypes of pollutants

Primary pollutantsPollutants that are

emitted directly from identifiable sources –produced by both natural events or human activities

Eg. Dust storms, emission from vehicles

Secondary pollutants

When certain chemical reactions take place among the primary pollutants

Eg. Sulphuric acid

Primary pollutantsPrimary pollutants

Carbon oxides (CO2 and CO)Nitrogen oxidesSulphur oxidesVolatile organic compounds –

hydro carbonsSuspended particulate matter

Primary air pollutants-Auto exhaust Primary air pollutants-Auto exhaust

hydrocarbons, methane, butane, propane others.

hydrogen sulfide, H2S, gas. Toxic. particulates, visible - dust,

smoke, soot, very fine <2.5 µm.lead, batteries, additive to

gasoline (phased out). Becomes airborne, spread to land

Primary air pollutantsPrimary air pollutants

Sulfur dioxide, SO2, colorless, odorless gas. particulates of SO4 which combines with water to form acid rain. Toxic to plants and animals; paint damage.

Carbon monoxide CO colorless, odorless gas, readily combines with hemoglobin in blood. Toxic.

Nitrogen oxides, NO, nitric oxide and nitrogen dioxide NO2. NO2 yellow brown to reddish gas. (NOx) Converted to nitrates in atmosphere causing acid rain.

Photochemical smog, brown air smog. Smog is smoke + fog.

Photochemical Smog Photochemical Smog Smog is a kind of air pollution,

originally named for the mixture of smoke and fog in the air.

HC and NO react in presence of sunlight to produce ozone and PAN (peroxy acetyl nitrate)

Nitrogen oxides + hydrocarbons + Ultraviolet radiation -----> Peroxyacetyl nitrate PAN + O3 ozone.

Photochemical smog- EffectsPhotochemical smog- Effects

breathing ozone results in respiratory distress, headaches.

PAN damages plantsPAH's polynuclear aromatic hydrocarbons, carcinogenic.

Photochemical SmogPhotochemical Smog

What are the effects of air pollution?

What are the effects of air pollution?

The effects of air pollutionThe effects of air pollution

reduces visual range and atmospheric clarity, less contrast, less visibility

damage to vegetation, including leaves, needles, fruit, growth rate, reproduction, hardiness.

Decline in net primary productivity NPP.

Crop losses 1.9-5.4 b/yr.


degradation of human health, from mild problems e.g. eye irritation, to severe e.g. respiratory disease asthma, bronchitis, emphysema, cancer.

CO, carbon monoxide, 90% natural, 10% from incomplete combustion, cigarettes, combines with hemoglobin and reduces bloods ability to carry oxygen. 150,000-350,000 deaths/yr.


degradation of vertebrate health, aquatic life, with impacts on respiration, bones, teeth, reproduction; increase lake acidity, decline in NPP

degradation of soil and water, when air pollutants settle, toxic metals in soil, soils leached

deterioration of man-made structures, break down car paint, roofing; acid rain chemically dissolves marble statues and other building materials

Effects of air pollutionEffects of air pollution

Air pollutants can overload or break down the natural defenses such as hair in our nose, sticky mucus in the lining of the upper respiratory tract causing diseases like lung cancer, asthma, chronic bronchitis etc.,

Effects of air pollutionEffects of air pollution Cigarette smoking is responsible for the

greatest exposure to carbon monoxide.Exposure to air containing even 0.001% of carbon monoxide for several hours can cause collapse, coma and even death.

CO is attached to blood hemoglobin reduces the oxygen carrying capacity of blood. This impairs perception and thinking, slows reflexes and causes headaches, drowsiness, dizziness and nausea and blurred vision.

Nitrogen oxides and suspended particles both can irritate lungs, aggravate asthma or chronic bronchitis and increase respiratory infections.

Many volatile organic compounds such as benzene and formaldehyde and toxic particulates such as lead and cadmium can cause mutations, reproductive problems and cancer, breathlessness and irritation of the eye, nose and throat.


Sulphur dioxide irritates respiratory tissues and chronic exposure causes bronchitis.

Sulphur dioxide also reacts with water, oxygen and other materials to form sulphur containing acids – The acids can become attached to particles which when inhaled are very corrosive to the lung.



Chronic exposure of the leaves to air pollutants can break down the waxy coating that helps prevent excessive water loss and leads to damage from diseases, pests, drought and frost.

It also affects photosynthesis, respiration and other metabolisms.

Doubling carbon dioxide

Doubling carbon dioxide

Doubling of carbon dioxideDoubling of carbon dioxide

In 1850, atmospheric carbon dioxide was about 280 parts per million (ppm).

Today, it is about 350 ppm. This increase is due largely to burning

of fossil fuels and clearing of forests. Oceans (and photosynthetic organisms)

currently absorb half of the carbon dioxide emitted.

Carbon dioxide concentrationCarbon dioxide concentration

Increase in carbon dioxide levels between 1960 and 1990.

Increase in carbon dioxide levels between 1960 and 1990.

Increase in the emissions of carbon during the interval from 1860-1995

Increase in the emissions of carbon during the interval from 1860-1995

Concentration of carbon dioxideConcentration of carbon dioxide

Cycle of carbon dioxideCycle of carbon dioxide

Impact of increasing CO2 levels in the atmosphereImpact of increasing CO2 levels in the atmosphere

Increased photosynthesis and productivity by the earth’s vegetation .

Increased plant production also means increased respiration .

Elevated atmospheric CO2 is global warming

Elevated CO2 means an increase in global temperature - the greenhouse effect.

Global temperatures may increase by 3oC-4oC by the end of the next century .

Green house effectGreen house effect

Greenhouse gases (GHGs)Greenhouse gases (GHGs)

Some greenhouse gases occur naturally in the atmosphere, while others result from human activities.

Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

Greenhouse gases (GHGs)

Greenhouse gases (GHGs)

Carbon dioxide is a product of burning fossil fuel and wood.

Nitrous oxide (NO2), produced by fertilizer use and released from decomposition of animal wastes.

Methane (CH4) is produced by bacteria from sediments, swamps, and in flooded rice paddies.

Chlorofluorocarbons (CFCs), Freon (a refrigerant) deplete the ozone layer in the upper atmosphere.

Halons, such as halocarbons), are released from fire extinguishers.

Water vapor in clouds reradiate heat back to Earth.

Green house gas emissionsGreen house gas emissions

Greenhouse gasesGreenhouse gases

Green house effectGreen house effectCarbon dioxide and other gases allow light to

pass, but trap heat in the atmosphere much like glass in a greenhouse traps heat.

This greenhouse effect is thought to be responsible for global warming.

Carbon dioxide contributes to only 56% of greenhouse heating.

The average surface temperature of Earth is about 15°C (59°F).

Global Warming is increase in the average temperature of the atmosphere, oceans, and landmasses of Earth.

AA

Greenhouse effectGreenhouse effect

Impact of Global warmingImpact of Global warming

1. Temperature extremes 2. Rise in sea level, and change in precipitation 3. Injuries from storms, coastal flooding 4. Interruption of power supply, contamination

of drinking water 5. Drought 6. Food shortages due to shift in agricultural

food production 7. Air pollution ( made worse by warming) 8. Asthma, bronchitis, emphysema

complications 9. Strain on public health systems 10. Increased need due to population migrations 11. Unable to contain spread of infectious

diseases

Conserve Energy Conserve Energy Be energy-wiseExplore alternativesRecycle as much as is possible. Take showers instead of baths.Check your taps. Check the lights Check your stove. Use less cooking water. Check the refrigerator.

Ozone depletionOzone depletion

Ground level Ozone Ground level Ozone

Ozone (O3) is a key constituent of the troposphere.

Ozone (Greek ozein, “to smell”), pale blue, highly poisonous gas with a strong odor.

Ozone is considered a pollutant at ground level.

Breathing O3 affects both the respiratory and nervous systems, resulting in respiratory distress, headache, and exhaustion.

Ozone is damaging to plants, resulting in leaf mottling and reduced growth.

The Ozone LayerThe Ozone Layer

Earth's atmosphere consists of a number of different layers.

The troposphere is the lower atmospheric layer.

The stratosphere is often referred to as the upper atmosphere.

The stratosphere contains the ozone shield, a layer of ozone (O3) in the stratosphere, 50 km above the ground.

The Ozone LayerThe Ozone Layer

Hazards of UV radiationHazards of UV radiation

Hazards of UV radiation include increased mutation rate, which can lead to skin cancer and cataracts, depression of the immune system, impaired crop and tree growth, and the death of plankton.

Health effects of Ozone depletionHealth effects of Ozone depletion

Each 1% drop in ozone is thought to increase human skin cancer rates by 4-6%.

The United Nations Environment Program predicts a 26 percent rise in cataracts and non-melanoma skin cancers for every 10% drop in ozone.

This translates to 1.75 million cases of cataracts and 300,000 more cases of skin cancer every year.

Ozone Hole above AntarcticaOzone Hole above Antarctica

During the 1980s scientists discovered a "hole" in the ozone over Antarctica. By the 1990s atmospheric scientists had detected an annual loss of 40-50% of the ozone above Antarctica, which produced an ozone hole every spring. One CFC molecule can destroy 100,000 ozone molecules.

The largest Antarctic ozone hole ever recorded (September 2006).

The largest Antarctic ozone hole ever recorded (September 2006).

The Antarctic ozone hole is an area of the Antarctic stratosphere in which the recent ozone levels have dropped to as low as 33% of their pre-1975 values.

What is acid rain; what are its causes and effects?

What is acid rain; what are its causes and effects?

Environmental Impact of Acid depositionEnvironmental Impact of Acid deposition

Sterilization of lakes and forests. Reducing the populations of small invertebrates and decomposers. Reducing agricultural yields. Causing extensive structural damage by corroding marble, metal, and stonework. Degrading water supplies by leaching heavy metals from the soil into drinking-water supplies. Increases in lung cancer and colon cancer.

Wet and dry acid depositionWet and dry acid deposition

Caused by SO2 and NO2. Alone cause dry acid deposition, with all forms of water vapor, these form sulfuric and nitric acid - acid rain downwind of sites of emission.

Logarithmic scale. pH of 4 is 10 x more acidic than pH of 5. Normal rain water pH 5.0-5.6 approx. Acid rain < 5.0 Affects industrialized areas worldwide. Scandinavia, Eastern Europe, N.E. U. S. Developing countries have more pollution, fewer controls than developed countries.

Acid Precipitation Acid Precipitation

Acid rainAcid rain The term "acid rain" is commonly used to mean the

deposition of acidic components in rain, snow, fog, dew, or dry particles.

The more accurate term is "acid precipitation.“ "Clean" or unpolluted rain is slightly acidic, its pH

being about 5.6, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid.

• H2O + CO2 → H2CO3 (aq) The extra acidity in rain comes from the reaction of

primary air pollutants, primarily sulfur oxides and nitrogen oxides, with water in the air to form strong acids (like sulfuric and nitric acid).

The main sources of these pollutants are vehicles and industrial and power-generating plants.

Acid RainAcid Rain

Nitric oxide & sulfur dioxide released primarily from electric power plants & motor vehicles

SO2 + water vapor + ozone --->

H2SO4

NO + sunlight + O2 ---> NO2 + various atmospheric gases ---> HNO3

Effects of Acid RainEffects of Acid Rain

Acidify lakes and disrupt the normal cycling of nutrients,

leaches metals out of rocks and soil,

kill fish, plants; stress and defoliate trees due to moss growth, insect attack, and loss of nutrients.

Acid rain - causesAcid rain - causes

The principal cause of acid rain is sulfur- and nitrogen compounds from human sources, such as electricity generation, factories and motor vehicles. Coal power plants are one of the most polluting.

What are the sources of indoor air pollution?

What are the sources of indoor air pollution?

Sources of indoor air pollutantsSources of indoor air pollutants

building materials, cigarette smoking, pesticides, volatile organics from

paints, furniture, rugs, insulation etc.

Sources of indoor air pollutionSources of indoor air pollution

11 common pollutants 2-5 times higher indoors than out

air inside car 18 times more polluted than air outside

17% of commercial buildings have serious indoor air pollution problems - sick building syndrome

Are there any natural indoor air pollutants?Are there any natural indoor air pollutants?

Radon gas accumulates in homes located in areas built on granites, phosphates, shales.

Synergistic effect with tobacco smoke; second leading cause of lung cancer

Sources: soils, groundwater, building materials.

Cannot be filtered out. Must be vented out.

Most dangerous indoor air pollutants Most dangerous indoor air pollutants

Cigarette smoke formaldehyde radioactive radon 222 gas asbestos Others include: bacteria, fungi,

dusts and other particulates, pollen, CO2, CO, O3, NOx, SO2, building materials such as fiberglass, etc.

Suggestions for the future: Suggestions for the future:

pollution prevention full cost pricing i.e. shift

costs to the production of air pollutants

improve energy efficiency reduce use of fossil fuels slow population growth

How serious is the problem of indoor air pollution?

How serious is the problem of indoor air pollution?

People with respiratory ailments are most affected Asbestos inhalation may cause: asbestosis, lung cancer, mesothelioma.

Asbestos workers, insulators pipe fitters, shipyard employees.

What are some of the symptoms of indoor air pollution?

What are some of the symptoms of indoor air pollution?

Irritation of mucous membranes,

coughing, dizziness, nausea, death.

General solutions:General solutions:

switch from coal to cleaner fuels - use natural gas

reduce energy use, improve energy efficiency

burn less coal, use lower sulfur coals. Coal gasification

After burning the SO2 can be cleaned out by scrubbing

taxing emissions

General solutions to indoor air pollution:

General solutions to indoor air pollution:

Ventilation: fans source removal: no smoking source modification: more

efficient stove design. pollutant removal: filters education

What are the special problems associated with

urban areas?

What are the special problems associated with

urban areas?

Urban trends:Urban trends:

discourage auto use, reduce number of cars stricter emission controls require electric cars improve public transport mandatory carpools industrial & household controls reduce emissions- burn less fuel, be energy

efficient control NOx by recirculating exhaust catalytic converters removes CO and

hydrocarbons by converting to CO2 and water effluent fees and emissions tests to assure

catalytic converters are maintained

Special problems associated with urban areas

Special problems associated with urban areas

Meteorological conditions along with topography can affect air pollution.

Natural ventilation occurs when winds are strong and turbulent, mixing is good, large mixing volume.

atmospheric inversion- temperature inversion, warmer air above cooler air, prevents dissipation of pollutants. pollutants collect, no wind.

Urban air pollutionUrban air pollutionUrban air pollution determined by:

rate of emission per unit area distance downwind that a mass of air can move

wind speed height of mixing

Thank youThank you

Air Pollution

Technology

Transcript of Air Pollution