Common Air Pollutants

Common Air Pollutants

	Common Air Pollutants Sulphur Dioxide It is one of the major air pollutants. It is emitted from burning fossil fuels like coal and petrol and from processing of sulphide ores like pyrite. When directly absorbed, SO₂ affects the morphology and physiology, and indirectly it leads to the formation of acids like sulphuric and nitric acid which are responsible for the low pH rain water. Spores of Alternaria tenuis, Fusarium moniIiforme are tolerant to SO₂ whereas spores of Rhizopus nigricans and Penicillium species are comparatively susceptible.
It is estimated that SO₂ from human activity introduced 6.6 million tons of sulphur into the atmosphere annually. Biologically produed H2S, when oxidised, produces SO₂. Effects SO₂ can damage materials and properties mainly through its conversion into the highly reactive H2SO4. It causes discolouration and physical deterioration of building materials and sculptures. Deterioration and fading are also produced in fabrics like cotton, nylon, leather and paper. It accelerates corrosion of metals, especially iron, steel and zinc. SO₂ has been found to affect vegetation adversely even at the concentration below 0.032 ppm. High concentrations of SO₂ over short period of time can produce acute leaf injury, such as necrosis in plants or brownish colouration in the tips of pine needles.
Lower concentrations over long period leads to chronic leaf injury such as gradual chlorosis. SO₂ and H₂SO₄ both are capable of causing irritation in the respiratory tracts of animals and humans and high concentrations of SO₂ cause severe heart and lung diseases. SO₂ causes chlorosis and necrosis of vegetation in as low concentration as 0.032ppm. Lichen vegetation is completely destroyed.
SO₂ pollution is related to higher death rate in aged persons. It kills fish and other animal life. Lichens and some bryophytes are found to be extremely sensitive to SO₂ pollution. The algal symbiont of a lichen thallus is most vulnerable to SO₂ pollution. They are regarded as indicators of SO₂ pollution.

Microbes and Atmosphere Part-2
Air Pollution
Pollutants
Common Air Polluntants
Air Polluntants Ozone
Air Polluntants Fluorides
Air Polluntants Corbon Monoxide
Air Polluntants Nitrogen Oxides
Air Polluntants Methyl Insocyanate Pollution
Air Polluntants Particulate Matter
Air Polluntants Carcinogenic Polluntants
Air Polluntants Asbestos
Air Polluntants Arsenic
Air Polluntants Nitrosamines
Greenhouse Effect
Photochemical Smog
Chlorofluoro Carbons

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