1. Control of Air pollution
Natural process of control
Meteorological factors
Anthropogenic Process
Control at source
after the release of pollutant

2. Meteorological factors & removal of pollution
The study of the dynamics of atmosphere that ultimately govern the air quality at a given point is known as meteorology.
Ambient lapse rate
Adiabatic Lapse rate
Atmospheric Stability

3. Temperature Inversion
In unusual case temperature may increase with increasing altitude, which is known as temperature inversion.
Causes of temperature inversion are
Radiation inversion
Subsidence inversion
Advective inversion
Maximum mixing depth & ventilation coefficient

4. Stack & Plume
The dispersion of emitted gases from the source of their production is known as plume and the source is known as stack.
On the basis of ELR & ALR the nature of plume may be different.
Coning Plume
Fanning plume
Looping plume
Neutral plume
Lofting plume
Fumigating plume etc.

5. Control at sources Control at sources can be of following types -
Source relocation
Source shut down
Fuel and energy substitution
Process change
Good operating condition
Installation of air pollution device

6. Control after release of pollution
Contamination of Air are done in 2 ways
1) SPM & ) Gas
Different process for controlling them

7. Control of gaseous pollution
It depend on the properties of specific gas to be controlled.
Common processes are –
Absorption in a liquid
Adsorption on a solid surface
Condensation to a liquid
Conversion to less polluting or non polluting gas.

8. Standard for air pollution control in India
The ambient air-quality standards have been prescribed for SO₂, SPM, CO, Nox.
These standards have been prescribed specially for
Industrial and mixed used areas,
Residential and rural areas
Sensitive areas

9. Collection of SPM
6 mechanisms are available for collecting polluting particles
Gravitational settling
Inertial impaction
Centrifugal impaction
Direct interception
Diffusion &
Electrostatic effects

10. Particulate collecting equipments
Gravity settling chambers
Cyclones
Scrubbers or wet collectors
Fabric filters / bag house
Electrostatic precipitators
Catalytic converter`

11. Values Area category Concentration micrograms per meter cube
SPM SO₂ CO NOx
Industrial & mixed used area
500
5000
120
Residential and rural
200 80
Sensitive
100 30

12. Air Quality standard – EPA
Sl no.
Parameter
Standard concentration
µg/ m ppm
Remarks 1.
SPM 75
260 -
Annual geometric mean
24 h 2.
Carbon mono oxide
10,000 9
8 hours 3.
Sulfur dioxide 80
365
.083
0.14
Annual mean 4.
Nitrogen dioxide
100
0.05 5.
Ozone
235
0.12
1 h daily maximum 6.
Lead
1.5
3 months average