Air Pollution:-

Any undesirable change in composition of air which is harmful for  living organism.

Causes of air pollution:-

• Burning of fossil fuel.
• Automobile exhaust.
• Industries
• deforestation

 Govt. has asked to keep foam solution, So  that Major part is absorbed.

1. It is used to remove suspended dust particle.
2. In this air must flow in a zig-zag manner. Here
3. The electrodes do corona radiation and Ioose e^-.
4. Velocity must be  very slow Inside so that enough time is there  for e^-  which help in deposition of dust  particle on plate .
5. e^-  along with dust  particle give –ve charge to dust particle.
6. It can remove more thqn 99% of suspended particle membrane of SPM from exhaust of thermal power plant.
7. It has electrode wire which are maintained at Several thousand volt which produce  corona and release e^-.
8. e^- attached with dust particle giving them net negative charge, it has conducting plates placed which is earthed & attract charged dust particles.
9. A scrubber can remove gases like SO₂.
10. Water vapour or lime is supplied in precipitator  which transfer gas to scrubber.

• Recently we have realized the danger of particulate matter which are very-very small in size and not removed  by such precipitators.  
• Acc. to CPCB (Central Pollution Control Board) the particulate matter having size less than 2.5 μm causes greater harm to human health.
• It get deposited in lungs and causes respiratory and breathing problem, Inflammation in lungs, Bronchitis and finally prematured death.

Avoidance of air pollution:-

• Use of automobile must be minimum.
• Proper maintenance of vehicular engine.
• Use of low sulphur containing diesel and petrol fuels.
• Use of lead free petrol and diesel.
• Use of catalytic converter in automobile engine; catalytic converter is made up of extensive costly metals like rhodium, palladium and platinum.
• It convert un-burnt  hydrocarbon into CO₂ and water. CO into CO₂ and NO into N₂ gas.
• Important:- Vehicular engine having catalytic converter advice to use lead full petrol and diesel because it inactivate the catalyst.

Note:- Only India uses CNG for running vehicle.

Only Brazil uses alcohol for running  vehicle.

Air prevention and control of pollution act is passed in 1981.

But in 1987 noise was also included as air pollution. environment protection act passed in parliament in 1986.