B.Sc. Second Year syllabus

1. AIR POLLUTION
DR. ASMITA DASPUTE .
ASSISTANT PROFESSOR ,
DEPT. OF ENVIRONMENTAL SCIENCE,
SBES COLLEGE OF SCENCE ,
AURANGABAD (MS).

2. COMPOSITION OF AIR

8. AIR POLLUTION SOURCES
• There are four main types of air pollution sources
• mobile sources – such as cars, buses, planes, trucks, and trains.
• stationary sources – such as power plants, oil refineries, industrial facilities,
and factories.
• area sources – such as agricultural areas, cities, and wood burning fireplaces.
• natural sources – such as wind-blown dust, wildfires, and volcanoes

10. • Mobile sources account for more than half of all the air pollution in the United
States and the primary mobile source of air pollution is the automobile,
according to the Environmental Protection Agency.
• Stationary sources, like power plants, emit large amounts of pollution from a
single location, these are also known as point sources of pollution.
• Area sources are made up of lots of smaller pollution sources that aren't a big
deal by themselves but when considered as a group can be. Natural sources
can sometimes be significant but do not usually create ongoing air pollution
problems like the other source types can.

11. DEFINATIIONS
• Aerosols: - Small solid or liquid particles (fine drops or droplets)
• that are suspended in air.
• Dust: - aerosols consist of particles in the solid phase.
• Smoke: - aerosols consist of particles in the solid and sometimes also liquid-phase
and the associated gases that result from combustion.
• Ash: - aerosols of the solid phase of smoke, particularly after it settles
• into a fine dust.
• Particulates: - Small particles, that travel in air and settles or lands on something.
• Fumes: - are polydispersed fine aerosols consisting of solid particles that often
aggregate together, so that many little particulates may form one big
• particle.

12. CLASSIFICATION OF POLLUTANTS
lutants can be classified as
atural contaminants
- Natural fog, pollen grains, bacteria, product of volcanic eruption.
rosols (particulates)
- dust, smoke , mists, fog, and fumes.
ases and vapours
- Sulphur compounds- So2, So, H2S
xygen compounds- O2, Co, Co2
rogen compounds- No, No2, NH3
logen compounds- HF, HCl
ganic compound- Aldehyde, Hydrocarbons
dioactive compounds- Radioactive gases

15. CLASSIFICATION OF AIR POLLUTION
• Air pollutants are classified as primary pollutants and secondary pollutants.
Secondary air pollutants are formed because of reactions between primary
pollutants and other elements in the atmosphere, such as the ozone.
• Primary air pollutants are directly emitted from the sources into the atmosphere.
• Typical air pollutants included under this category are:
• (i) Inorganic gases such as SO2, NOX, H2S, CO, NH3, CO2, HF.
• (ii) Particulate matter like ash, smoke, dust, fumes, mist, spray.
• iii) Olefinic and aromatic hydrocarbons
• (iv) Radioactive compounds.

16. SECONDARY POLLUTANTS
Secondary Pollutants are those which are derived from the primary pollutants due to
chemical or photochemical reactions in the atmosphere.
Pollutants such as SO2, NO2, O3, sulphate and nitrate salts, aldehydes and
peroxyaceiyl nitrate (PAN) are included in this category.

17. ACCORDING TO SATE OF MATTER
• :
• 1. Gaseous pollutants
• 2. Particulate pollutants
• 3. Aerosols
• 4. Metallic components
• 5. Radioactive pollutants
• 6. Pesticides

18. GASEOUS POLLUTANTS
Gaseous PollutantsDescription
Impacts
Gaseous PollutantsDescription
Impacts
Gaseous PollutantsDescription
Impacts
Carbon monoxide (CO) •Highly toxic.
•Produced from internal combustion
engines due to incomplete combustion.
•Other sources are volcanoes, forest fires,
etc.
•Greenhouse gas.
•Carbon monoxide poisoning.
•Produces carboxyhemoglobin reducing
the oxygen-carrying capacity of the
blood.
Carbon dioxide (CO2) •Heavier than air.
•Source are volcanoes, fire, etc.
•Greenhouse gas.
•CO2 is an asphyxiant gas (asphyxia: a
condition arising when the body is
deprived of oxygen, causing
unconsciousness or death.).
•Has other harmful effects if a high
concentration of CO2 is inhaled like
dizziness, headache, etc.
•Carbonic rain in high polluted areas.
Chlorofluorocarbons (CFCs) •Used in refrigerators, air conditioners,
aerosols, etc.
•Highly destructive to the Ozone layer.
Ozone (O3) •Very useful in the Stratosphere but •Has toxic effects.

19. GASEOUS POLLUTANTS:
• Nitrogen Oxides, NOX:
• The oxides of nitrogen are N2O, NO, NO2, N2O3, N2O5.
• The atmospheric background concentrations are:
• N2O (0.25 ppm), NOx(0.1 to 2 ppm) and
• NOX (0.5 to 4 ppm).
• In air, NOX is converted into nitric acid by natural processes which is one of the constituents of
acid rain.

20. SULPHUR OXIDES, SOX
•Combustion of sulphur bearing materials produces SO2 and a little
quantity of S03.
• Global emission of SO2 from natural sources like biological decay
(H2S), sea spray and volcanic activity is 90, 40 and 5 million tonne
per year while from anthropogenic sources such as coal, petroleum,
smelting and sulphur production, it is 92, 26, 14 and 2 million tonne
per year respectively.

21. CARBON MONOXIDE, CO.:
•CO, produced by incomplete combustion of fuel, is the major
individual pollutant with a tonnage matching that of all other
pollutants together.
• Global emission of CO from natural sources amounts to 3364 million
tonne per year.

22. PARTICULATE POLLUTANTS:
•Small solid particles and liquid droplets are termed particulates.
• Their number varies from several hundred per cm3 in clean air to
more than 100,000 per cm3 in highly polluted air.
• Man made sources for particulate emission include flyash from power
plants, smelters, fuel combustion, industrial operations, refuse burning
etc.
•Every year natural sources discharge 800 to 2000 million tonne and
man-made sources 200 to 500 million tonne of particulates.

23. PARTICULATE SIZE RANGES FROM 0.001 TO 500 MICROMETERS (M) IN DIAMETER.
Heavy Particulate Matter Suspended Particulate Matter Nanoparticulate Matter
•More than 10 µm •Less than 10 µm •Less than 0.02 µm
•Settles down after a point •Floats and moves freely with air
currents
•Very light and harmful
•Form aerosols