3. TYPES OF POLLUTANTS
Primary air pollutants
Those pollutants which emitted directly into the
atmosphere and remain in the atmosphere in its
original form are “primary ”.
Examples: sulphur compounds, CO, oxides of
nitrogen and radioactive compounds
4. Secondary air pollutant
Those pollutants which are produced by the
interaction among two or more primary
pollutants are called “secondary pollutants”
Examples: Ozone, PAN, acid mist,
photochemical smog.
5. CLASSIFICATION OF
POLLUTANTS WITH SOURCES
Pollutants Sources
1. Natural contaminants
• Fog, pollen grains ,bacteria,
products of volcanic eruption
•Size 10µ to 50µ.
• wind pollination of weeds,
grasses and trees.
• volcanic eruption
6. 2. Aerosols Sources
•It is the dispersion of solid or liquid
particles of microscopic size in gaseous
media.
•Size 0.01µ to 100µ
a) Dust :
• it is a solid particle that can capable of
temporary suspension in air
• Size >20µ
b) smoke:
• It produces due to incomplete
combustion of fuel
• Size < 1µ
c) Mist : it is low concentration dispersion
of liquid particle of larger size ranging
from 500 to 40µ
d) fog: it is high dispersion of liquid particle
of smaller size ranging from 40µ to 1µ.
e) smog: it is a combination of smoke and
fog.
Combustion of fuel, house cleaning, engine
exhaust
Coal, wood , oil
Condensation of water vapours
(thin fog)
Atmospheric photochemical reaction
8. 3) Gases and vapours Sources
a) Sulphur dioxide(SO2)
b) Oxide of Nitrogen: it includes NO2
NO
c) Carbon monoxide (CO)
d) Hydrogen Sulphide (H2S)
e) Ozone
f) Radioactive gases
Combustion of coal , muncipal
incineration, paper manufacturing
plant.
Nitric acid plant, automobile exhaust,
power plant and furnace.
Incomplete combustion of
carbonaceous materials, automobile
exhaust, coal mines.
Anaerobic processes, petroleum
refineries
Combustion and sunlight
Nuclear power plant, testing of
nuclear bomb.
10. Way to stop air pollution
Recycling newspaper, aluminum, and
others
Planting trees
Avoid purchasing products that contain
CFCs
Supporting much stricter clean air laws
and enforcement of international
treaties to reduce ozone depletion and
slow global warming
11. Driving a car that gets at least 35
mpg
Walking and using public
transportation
Using CFL bulbs over incandescent
bulbs
Buying only energy efficient
appliances