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78%

21%

1%0-4% 0.04%

Percentage Composition of Gases

Nitrogen

Oxygen

Argon

Water Vapour

Carbon dioxide

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The effect of air pollutant depends on their

concentration, their relative toxicityand the

average length of timethey remain in theenvironment before becoming harmless by

natural processes.

Two types of air pollutant: -

1) Primary pollutants: which are emitted directly

into the atmosphere.

2) Secondary pollutants: which are produced when

primary pollutants undergo chemical change in

the atmosphere.

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Anthropogenic

Causes

NaturalCau

ses

Industrial plants that produce smoke(soot) Combustion of fossil fuels

Volcanic eruptions

Forest fires

Dust

Pollen

They can cause respiratory problems, cancer

and smog.

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=ew4MKimKD1ZQ-M&tbnid=11zZY2a5x4auAM:&ved=0CAUQjRw&url=http://www.gassaferegister.co.uk/learn/carbon_monoxide_kills.aspx&ei=VdKNU7GRDZKRuATWroD4Dw&bvm=bv.68191837,d.c2E&psig=AFQjCNHPLe2nnLpWrMasnJeiJoIcHUpOhw&ust=1401889744868924http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=utBS6rsCghTQLM&tbnid=Ox5grUH76pzx1M:&ved=0CAUQjRw&url=http://www.greendiary.com/hazardous-effect-of-particulates-may-lead-to-gene-reprogramming.html&ei=HNKNU8nQIMrHuATn6YDYDw&bvm=bv.68191837,d.c2E&psig=AFQjCNFLCiB9GUsEoyBgelXCRydHn0KZtQ&ust=1401889148043270

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Anthropogenic

Causes

NaturalCau

ses

Incomplete combustion of fossil fuels Fuel + O2CO + H2O

Incomplete oxidation of methane in

atmosphere

2CH4+ 3O22CO + 4H2O

Methane is from anaerobicdecomposition in bacteria

They prevent haemoglobin from transporting

oxygen.

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=ew4MKimKD1ZQ-M&tbnid=11zZY2a5x4auAM:&ved=0CAUQjRw&url=http://www.gassaferegister.co.uk/learn/carbon_monoxide_kills.aspx&ei=VdKNU7GRDZKRuATWroD4Dw&bvm=bv.68191837,d.c2E&psig=AFQjCNHPLe2nnLpWrMasnJeiJoIcHUpOhw&ust=1401889744868924

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Anthropogenic

Causes

NaturalCau

ses

High temperature combustion in enginesproduces NO, which is then oxidized.

2NO + O22NO2

Bacterial actions in soil produces NO

In atmosphere, NO is oxidized to NO2 2NO + O22NO2

They can cause acid deposition, respiratory

problems and smog.

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=8riHp6tpF7LIxM&tbnid=lwfMBFfKRFpJkM:&ved=0CAUQjRw&url=http://www.dec.ny.gov/chemical/8418.html&ei=ZdaNU5O5NtiXuASbnYLIBw&bvm=bv.68191837,d.c2E&psig=AFQjCNGiMSBplGUIwEoO2UW1-tj9oMvNBQ&ust=1401890526062141

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Anthropogenic

Causes

NaturalCau

ses

Combustion of sulfur containing coal ordiesel, smelting, sulfuric acid plants

S + O2SO2

2SO2+ O22SO3

Volcanic eruptions

2H2S + O22SO2+ H2O

2SO2+ O22SO3

They can cause acid deposition and

respiratory problems.

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=Nta94h3qQu_VMM&tbnid=Djk3QUIHxh68YM:&ved=0CAUQjRw&url=http://www.dailygalaxy.com/my_weblog/2012/05/super-volcanic-eruptions-with-the-potential-to-end-civilizations-new-discovery-1.html&ei=o9aNU-3aF9aMuASisoDoDg&bvm=bv.68191837,d.c2E&psig=AFQjCNEFtpGcIknXkK1xixe-LvyMb0rNag&ust=1401890841536671

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Anthropogenic

Causes

NaturalCau

ses

Incomplete combustion Paint

Cleaning supplies

Anaerobic decomposition forms Methane

They cause smog and cancer.

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=9L47kHCh2lVk2M&tbnid=uZmP5NuSgOZsCM:&ved=0CAUQjRw&url=http://greenopedia.com/article/being-aware-vocs&ei=sdiNU8S4MYe8ugSZgILwCA&bvm=bv.68191837,d.c2E&psig=AFQjCNGwpI1ZNdNxwDFUvl060HJHsXAtXw&ust=1401891279733275http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=LjiMOq4rPkUzbM&tbnid=YYePlie1AeDJRM:&ved=0CAUQjRw&url=http://environmentaljournalismcanada.wikispaces.com/Air+pollution&ei=W9iNU9fYK8SeugSvrYGoAw&bvm=bv.68191837,d.c2E&psig=AFQjCNGwpI1ZNdNxwDFUvl060HJHsXAtXw&ust=1401891279733275

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1. Catalytic Converters

CO:2CO + O22CO2NO:2CO + 2NO2CO2+ N2

VOCs: no one reactions but,

VOC + O2CO2+ H2O

Hot gases are passed over a platinum catalystwhere they adsorb to the surface. (This is about

90% efficient at reducing pollutants.)

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=auNkZMwHkJdTFM&tbnid=uEaWjseCBVntEM:&ved=0CAUQjRw&url=http://www.preciousmetals.umicore.com/recyclables/SAC/CatalyticConverter/&ei=ta2OU6rYIIHi8AWO2oHACQ&bvm=bv.68235269,d.dGc&psig=AFQjCNFyBV_24OwXAeRAda8aai0ebLYnmQ&ust=1401945894536701

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http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=auNkZMwHkJdTFM&tbnid=uEaWjseCBVntEM:&ved=0CAUQjRw&url=http://www.preciousmetals.umicore.com/recyclables/SAC/CatalyticConverter/&ei=ta2OU6rYIIHi8AWO2oHACQ&bvm=bv.68235269,d.dGc&psig=AFQjCNFyBV_24OwXAeRAda8aai0ebLYnmQ&ust=1401945894536701http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=auNkZMwHkJdTFM&tbnid=uEaWjseCBVntEM:&ved=0CAUQjRw&url=http://www.preciousmetals.umicore.com/recyclables/SAC/CatalyticConverter/&ei=ta2OU6rYIIHi8AWO2oHACQ&bvm=bv.68235269,d.dGc&psig=AFQjCNFyBV_24OwXAeRAda8aai0ebLYnmQ&ust=1401945894536701

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2. Control of Fuel to Air Ratio

NO:Lean burn engines

NO is produced at high temperatures in anengine. Decreasing oxygen input will lower the

temperature, producing less NO. However, a

decrease in oxygen will increase incomplete

combustion, creating more CO and VOCs. Abalance has to be met of reducing NO while not

increasing CO and VOCs too much.

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3. Alkaline Scrubbing

SO2:CaCO3(s) + SO2(g)

CaSO3(s) + CO2(g)

Alkaline water is sprayed

onto the exhaust gases.

The sulfur dioxide gas is

then precipitated out andcan be collected. (It can

reach 95% efficiency)

http://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=V8j8lVSwiAB27M&tbnid=qXBQhUzY6CRcCM:&ved=0CAUQjRw&url=http://www.globalspec.com/learnmore/manufacturing_process_equipment/air_quality/scrubbers&ei=ebCOU4n5L4P58QWIgoGwBg&bvm=bv.68235269,d.dGc&psig=AFQjCNGjlTS4w9r_EmA7i1_mpm3DWSGoxQ&ust=1401946608483888

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4. Limestone (CaCO3) Fluidized Beds

SO2:CaO(s) + SO2(g)CaSO3(s)

Limestone is mixed with the coal beforecombustion. During combustion, calcium oxide is

produced from the limestone, and that reacts

with the sulfur dioxide. (It can reach 95%

efficiency and no production of CO2 which isgreenhouse gas!)

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Ionizing rods Charged plate (+)

Becomenegative here