Air Pollution: It refers to any physical, chemical or biological alteration in a part
or whole of the atmosphere of the earth that affects the living organisms and
human property by lowering the quality of air.
Air Pollutant: Any physical, chemical or biological factor that leads to a decline in
the quality of air by altering it.
2 Types:
1. Primary Air Pollutant: They are the pollutants that are emitted as such
from source. Eg – CO, SO2, NOx,
2. Secondary Air Pollutant: They are pollutants that are formed in air from
primary components by their chemical reactions. Eg – Acid Rain, PAN.
Air Pollutants, Sources, Effects & Control:
CO –
Sources:
1. Incomplete combustion of fossil fuels.
2. Automobile exhaust fumes – 60%
3. Burning of municipal waste.
4. Forest fires.
Effects –
It has high affinity for haemoglobin present in blood, combines with it readily
and reduces the oxygen carrying capacity of blood.
It can be fatal on prolonged exposure.
In low concentrations, it causes nausea, dizziness, vomiting, suffocation and
asphyxiation.
Control –
1. Complete combustion of fossil fuels at power plants.
2. By raising temperature of combustion in automobile engines above
1700DegCelcius.
3. Not burning municipal waste.
NOx (Nitrogen oxides) –
Sources:
1. Automobile exhaust fumes
2. Paper Mills effulgence
3. Complete combustion of fossil fuels at high temperature.
4. Burning of municipal waste.
Effects –
On humans:
Nox cause irritation of nasal tract and anesthetize the nose at low
concentrations.
They cause respiratory problems like asthma and bronchitis in persons having
weak respiratory tracts.
At high concentrations, they are fatal.
On plants:
They cause increase in length and hereby curling of leaves of plants (Necrosis)
Control –
1. If wet scrubbers are installed in industrial plants, Nox are washed away
by continuously sprinkled water.
2. Control methods have to be exercised.
SO2Sources –
Volcanic Eruption, Forest fires, burning of low-grade coal and petroleum that
contains sulphur (diesel has high sulphur content)
Effects –
I fucking don’t know.
Control –
1. Wet scrubbers in industries to absorb SO2
2. If conc. Is high, Water is replaced by Ca(OH)2. (90% efficiency)
3. If Ca(OH)2 doesn’t work, DMA is used as absorbing agent. (99%
Efficiency)
SPM (Suspended Particulate Matter)
2 types:
1. Respirable SPM (0.1 to 10 um)
2. Non- Respirable SPM ( > 10 um)
Effects:
Respirable SPM penetrate the alveoli walls in lungs and gets dissolved in blood
stream. Consists of fine grains of diameter 0.1 to 10 um.
Non-Respirable SPM cause irritation in nasal tract of humans and result in
formation of mucous.
Sources:
Volcanic eruptions, forest fires, sand storms, construction and woodwork,
industries, burning of fossil fuels, drilling and sawing.
Control:
SPM Filtering:
Settling Chamber  Fabric Filter  Cyclone  Electrostatic Precipitator
Ambient Air Quality Standars in India:
Acid Rain:
Acid Rain refers to the lowering of pH of rain so that it becomes acidic in nature
by formation of acids in atmosphere. It is a secondary air pollutant.
Oxides that cause acid rain:
SO2
NOx
CO2
Reactions –
SO2 + H2O  H2SO3
NOx  NO + [O]
SO2 + [O]  SO3
SO3 + H2O  H2SO4
H2O  OH- + H+
NOx + OH-  HNO3
CO2 + H2O  H2CO3
Types:
Wet Acid Rain: This type of acid rain is mild in nature. It occurs when acid
droplets settle on dust particles to make them acidic and then these acidic dust
particles are engulfed as condensation nuclei by water vapor.
Dry Acid Rain: This type of acid rain is more severe. It occurs when the acid
droplets in the atmosphere directly precipitate.
Effects:
On plants and animals:
1. It blocks stomata of leaves and hence lower transpiration of plants
ultimately causing them to dry up.
2. It leaches chlorophyll causing yellowing of leaves (chlorosis)
3. It causes dissolving of eggshell in singing birds.
4. Degrades quality of soil (makes it less fertile).
5. Affects medicinal plants in adverse way.
6. Water turns red in color, aquatic life is affected.
On monuments and materials:
1. Causes flaking of Marble (Blistering of marble) as in case Taj Mahal
2. Reduces strength of structural materials (Mathura oil refinery buildings)
3. Paper loses brightness.
4. Cloth and leather lose strength
Global Warming:
Increase in average temperature of the earth is called global warming.
It occurs due to greenhouse effect.
Greenhouse effect is the trapping of sun’s infrared radiation in the atmosphere of
the earth that increases temperature.
Greenhouse Gases:
1. CH4
2. CO2
3. NOx
4. CFC
5. H2O vapour
6. SF6
Global Warming effects:
Melting of polar ice caps  Increase in water level  Percolation of water into
rocks  Landslides  Deforestation  Land exposed to radiation  Melting of
ice caps. (Make in form of a cyclic diagram)
Positive Feedback : Occurrence of one event increases the intensity of the other.
Fuck El Nino and Ozone Hole, seriously, FUCK EM.