INTRODUCTIONThe atmospheric air contains about 79% of nitrogen and 21%of oxygen and the negligible traces of other elements such ascarbon dioxide, methane, carbon monoxide, ammonia,sulphurdioxide, etc. are found, which have practically noadverse effect.This air is considered as pure or healthy and is always desirablefor human life, animal life and plant life.
But due to various factors the balance of nitrogen and oxygenis getting disturbed gradually and is causing adverse effectson human health, animal life, plant life and other materials ofthe universe.So, the accumulation of destructive elements in the air fromthe natural or unnatural sources is termed as air pollution.
CAUSES OF AIR POLLUTIONl. Increase in population and traffic2. Development of industries3. Development of automobile engineering4. Development of agriculture5. World wide arms race6. Thermal and nuclear power
Increase in PopulationDue to the increase in population, the residential areas of atown or city are being enlarged by destroying the forest areas,trees, jungles, etc. which have the property of absorbing carbondioxide and releasing oxygen.Due to the generation growth in population the systems ofsanitation have also become a matter of grave concern in a townor city.Again, the manufacturing units of house construction materialssuch as bricks, cement, stone chips, etc. impart muchpollutants in air.
Development of IndustriesThe development of industries such as fertilizer industry,chemical industry, metallurgical industry, petroleumindustry, tanning industry, paper industry, etc. dischargepoisonous gases and waste products.
Development of Automobile EngineeringDue to the development of automobile engineering, thevehicles of petrol and diesel engines are going on increasingin urban areas.The towns and cities are crowded with buses, minibuses,cars, taxies, etc. which are releasing much carbon monoxidein the air regularly.
Development of AgricultureDue to the development of agriculture, improving the yieldof crop has become easier. So, the application of chemicalfertilizer and insecticides have become a trend. Such thingsare also responsible for air pollution.
World Wide Arms RaceAll the countries in the world have a tendency to obtain morepower than the others by creating nuclear weapons and otherexplosives.The nuclear explosions are carried out on the surface of theearth for the purpose.The radioactive substances from such explosions are pollutingthe atmospheric air.
Thermal and Nuclear PowerGenerationDue to the development of civilization, the demand of electricpower has increased many folds.To meet the excessive demand of power, the thermal andnuclear power generation plants have become an urgent need.The fly ashes and radioactive ashes generated from such plantsare polluting the atmospheric air.
(a) Smoke It is produced chiefly due to the incompletecombustion of fuel such as coal, oil, petroleum, etc.It contains carbon monoxide, carbondioxide, etc.(b) Dust It is finely divided powder-like matters generated bycrushing or grinding of stones, disintegration of stones or otherinorganic substances.
(c) Gases These are formless fluids which can betransformed to liquid state by the change of temperature andpressure. These are formed by the decomposition of organic matters orburning of fuels.d) Aerosol The dispersion of microscopic solids or liquidsin the atmosphere is termed as aerosol.
(e) Particulate Matter The matter which isgenerated from the sources such as industries, power generationplants, road-way dust, etc. and exist in atmosphere in suspension isknown as particulate.(f) Pollen The fertilizing or reproductive matters of flowersto form seeds is known as pollen.The pollen can float in air or it can be transferred from flower toflower by bees or butterflies.
(g) Sulphur Dioxide (SO2) It is generated fromthermal power plants petroleum industries, oil refineries. acidmanufacturing plants, etc.It causes respiratory diseases, irritation of throat and eyes, etc.
(h) Hydrogen Sulphide (H2S)It is generated from sewagetreatment plants, tanning industries, dye manufacturing, etc. It causes irritation and disorder of respiratory organ, etc.(i) Nitrogen Oxide (NO) and Nitrogen Dioxide (NO2) Theseare generated from explosive manufacturing industry, automobile workshop,acid manufacturing plant, etc. It causes bronchitis and edema (excess fluid: a buildup of excess serous fluid between tissue cells )of lungs,etc.
(J) Hydrogen Fluoride (HF) It is generated from chemical industry,fertilizer industry, aluminium industry, etc. It causes skin diseases and bone fluorisis, etc.(k) Hydrogen Peroxide (H202)It is generated from photochemical smog products. It causes lungs irritation.(l) Carbon Monoxide (CO) and Carbon Dioxide (CO2) It isgenerated from automobile exhaust, blast furnace, fuel gases, etc. It is a poisonous gas and causes damage to the respiratory organ.
(m) Hydrocarbon It is generated from automobileexhaust.It causes disease of respiratory organ.(n) Arsenic It is generated from detergents, pesticides,etc.It causes skin diseases.