Air Pollution:-
Air pollution is the addition of particles, gases and chemicals into the atmosphere that have the potential to adversely affect human health, health of animals, vegetation, natural resources and human assets.
Cause of Air Pollution:-
(i) Combustion of natural gas, petroleum, coal and wood is industries, automobiles, aircraft, railways, thermal plants, agricultural brning, kitchens, etc.
( Soot, flyash, CO2,CO, Nitrogen Oxide, SO2)
(ii) Metallurgical Processing
(iii) Chemical industries including pesticides, fertilizers, weedicides, fungicides.
(iv) Cosmetics
(v) Processing industries like cotton textile, wheat flour mills, asbestos
(vi) Welding, stone crushing, gem grinding, etc.
Primary Air Pollutants and their Effects:-
Primary Air Pollutants:-
Particular matter, CO, CO2, H2S, Hydrocarbons, SO2, Nitrogen oxide etc.
(i) Particular matter:- It consists of soot, flyash, dust of various types, fur, hair, spores, pollen grains etc. They pass deep into the lungs causing breathing and respiratory problems, irritation, inflammation and damage to lungs resulting is pre-mature *****.
(ii) CO:- It is produced due to incomplete combustion, metallurgical operation and naturally by plants as well as animals. 50% emission are from automobiles. CO combines with haemoglobin, produces carboxyhaemoglobin (COHb). It impairs oxygen transport resulting in giddiness, headache, decreased vision, cardiovascular malfunction and asphyxia.
(iii) CO2:- In excess it causes headache and nausea.
(iv) H2S:- It causes mottled chlorosis and defoliation in plants, decolourises paints, produces eye irritation, throat irritation and nausea.
(v) Hydrocarbon(HCs) or Volatile Organic Carbons (VoCs):- Hydrocarbons, especially polynuclear aromatic (PAH) and formaldehyde are carcinogenic, cause irritation of eyes and mucous membrane and bronchial constriction. There is increased mucus secretion and tearing of alveoli.
(vi) SO2:-
(a) It causes chlorosis and necrosis of vegetation.
(b) SO2, above 1 ppm affects human beings. If causes irritation to eyes and injury to respiratory tract (asthama, bronchitis, emphysema).
(c) It results in discolouration and deterioration, sculptures, painted surfaces, fabrics, paper, leather etc. The reported threat to Taj Mahal of Agra from nearby refinary of Mathura is on account of it.
(vii) Nitrogen oxide:- (N2O, NO, NO2, N2O4, N2O5)
(a) They have a corrosive effect on metals
(b) They cause fading and deterioration of different types of textiles
(c) They produce lesions, necrosis, defoliation, back and ** of many plants
(d) they cause eye irritation, respiratory troubles, lung edema, blood congestion and ditetion of arteries
(viii) Fluorides:- In animals, fluorides bring about abnormal calcification of bones and teeth (making them weak), frequent diarrhoea and swelling of knee bones. In human there is motting of teeth, weak bones, boat-shaped posture, knocking knees, gastrointestinal and neuromuscular disorders.
