Write a short note on air pollution and its prevention.

Air pollution: Air pollution may be defined as 'the presence of one or more contaminants such as fumes, dust, gases, mist, smoke, odour, smog or vapours in the outdoor atmosphere which is injurious to human, animal and plant life or which unreasonably interferes with the comfortable enjoyment of life and property"
There are two types of air pollutants which cause air pollution:
(i) Primary air pollutants:
Natural pollutants- Bacteria, pollens, product of volcanic eruptions
Aerosols-Dust, smoke, mist, fog
Gases- ${CO}_2,CO,{SO}_X,{NO}_X$ hydrocarbons etc
(ii) Secondary air pollutants
eg Smog- mixture of smoke, fog, air and other chemicals
Prevention of air pollution:
The following methods are used for the prevention of air pollution:
Zoning
Control of air pollution by sources
Control of air pollution by using devices
Control of air pollution by means of stacks
Control of air pollution by growing vegetation