UNIT_1
AIR
POLLUTION

what is air pollution?
• Air pollution is the excessive concentration of
foreign matter in the air which adversely
affects the well being of the individual or
causes damage to the property.
~American Medical
Association
• It is the disturbance caused due to presence of
unwanted, impure & harmful particles in the
air or atmosphere.

Why should we study air pollution?
 Air pollution can cause death, impair health, reduce visibility, bring about
vast economic losses & contribute to general deterioration of both cities
and country-side.
 It can cause intangible losses to historical monuments such as Taj Mahal
which is believed to be badly affected by air pollution.
 The study on air pollution helps engineers to apply their ingenuity &
problem-solving abilities to eliminate air pollution where it exists and
restoring the natural environment.
 Example : Invention of E-Bikes to reduce the risk of pollution
caused by bikes consuming petroleum products

Normal composition of air
Nitrogen(78%)
Oxygen (20.6%)
carbondioxide and other
gases (0.03%)
inert gases (mainly Argon)
(0.97%)
water vapour (1%)

Sources of air pollution
S.No. Class Aerosols Gases and Vapours
1. Combustion processes (domestic burning,
thermal power plants, aeroplanes &
railways.also refuse burning)
Dust, fume, smoke. SO2, NO2, CO, organic
vapours, odours.
2. Chemical processes Dust, fume, mist SO2, CO, NH3, NO2,
(process dependent)
3. Petroleum operations Dust, mist SO2, H2S, NH3, CO,
hydro-carbons,
mercaptants.
4. Metallurgical process Dust, fume SO2, CO Fluorides,
organic vapours.
5. Mineral processing Dust, fume SO2, CO, Fluorides,
organic vapours
6. Food & Feed Operations Dust, mist Odourous materials,
organic phosphates
7. Agricultural activities Dust, mist, smoke, fly ash organic vapours
8. Nuclear energy programmes Dust Radioactive gases

Episodes of air pollution
• Episodes of air pollution are disastrous air pollution events in the world.
• Some of them are:
S.No
. Month and year Place Mortality
1. December, 1930
Meuse Valley
(Belgium) 63
2. October, 1948
Donora
(Pennsylvania) 20
3. November, 1950
Poza Rica
(Mexico) 22
4. December, 1952 London 4000
5. November, 1953 New York 220
6. January, 1956 London 1000
7. December, 1957 London 750
8. December, 1984 Bhopal (India) 2000

Images of the incidents
Meuse
Valley
Donora Bhopal

Classifications of air pollutants
Pollutants
Natural
Contaminants
Natural fog, Pollen
grains, bacteria,
etc.
Aerosols
(Particulates)
Dust, smoke,
mists, etc.
Gases &
Vapours
SO2, O3, NO2
etc.

1. Natural Contaminants
• Natural Contaminants occur due to natural
phenomena itself.
• These include volcanic eruptions, natural fog,
pollen grains, bacteria.
• These air-borne pollutants are significant
because of the allergic responses produced in
sensitive individuals.

Volcanic Eruption

2. Aerosols
• Aerosols refer to dispersion of solid or liquid
particles of microscopic size in gaseous media,
such as dust, smoke, or mist.
• It can also be defined as a colloidal system in
which the dispersion medium is gas &the
dispersed phase is solid or liquid.
• It includes dust, smoke, mists, fog, fumes etc.

3. Gases
• The following are some of the gases in the air
pollutants.
Sulphhur
Dioxide
• The main
source is the
combustion of
fuels.
Hydrogen
Sulphide
• Due to
Anaerobic
Biological
decay process
on land, in
marshes & in
oceans.
Ozone
• It exists in
great
abundance
under natural
conditions in
the upper
atmosphere.

Other Classification of air pollutants
• Primary air pollutants:
Primary air pollutants are
those which are emitted
directly from identifiable
sources.
 Secondary air Pollutants:
Secondary air Pollutants are
those which are produced in
the air by the interaction
among two or more primary
pollutants, or by reaction with
normal atmospheric
constituents, with or without
photoactivation.

Examples of primary air pollutants
• Finer particles (less than 100 µ in diameter)
• Coarse particles (greater than 100 µin diameter)
• Sulphur Compounds
• Oxides of nitrogen
• Carbon monoxide
• Halogen compounds
• Organic compounds
• Radioactive compounds

Examples of secondary air pollutants
• Ozone
• Formaldehyde
• PAN (Peroxy Acetyl Nitrate)
• Photochemical smog
• Formation of acid mists (H2SO4) due to reaction of
sulphur dioxide and dissolved oxygen,
when water droplets are present in the
atmosphere.

Classification according to Emission
Inventory Source
Total
Sources
Stationary
Sources
Point
Sources
Area
Sources
Mobile
Sources
Line
Sources
Area
Sources

Sub classifications
Point
Sources
Industrial
processing
Power Plants
Fuel
Combustion
(coal, oil, gas)
Solid Waste
disposal
Miscellaneous
Area
Sources
Residential
heating
Institutional &
Commercial
heating
On site
incineration
Open burning
Evaporative
losses
Miscellaneous
Line
Sources
High way
Vehicles
Railroad
Locomotives
Channel Vessels
Area
Sources
Motor Vehicles
(light, medium,
heavy duty)
Railyard
Locomotives
Port Vessels
Aircraft
(airports)
Miscellaneous

Thank you
Prepared by
M.Faiyaz Ahmed Khaleel