AIR POLLUTION

Air is the name given to atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78.09%nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. While air content and atmospheric pressure vary at different layers, air suitable for the survival of terrestrial plants and terrestrial animals is currently only known to be found in Earth's troposphere and artificial atmospheres. Air is mainly composed of nitrogen, oxygen, and argon, which together constitute the major gases of the atmosphere. The remaining gases are often referred to as trace gases, among which are the greenhouse gases such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other chemical compounds. Many natural substances may be present in tiny amounts in an unfiltered air sample, including dust, pollen and spores, sea spray, and volcanic ash. Various industrial pollutants also may be present, such as chlorine (elementary or in compounds), fluorine compounds, elemental mercury, and sulfur compounds such as sulfur dioxide [SO2]. This project examines the effects of the above mentioned pollutants. Air pollution may be defined as the presence in the air of one or more contaminants in such quantities and of such durations as may be or tend to be injurious to human, animal or plant life, or property SOURCES OF AIR POLLUTION Natural: Natural sources of sulphur dioxide include release from volcanoes, biological decay and forest fires Man made sources :Deforestation, Emissions, Explosives used in wars, AIR POLLUTION CLASSIFICATION Primary air pollutants - Materials that when released pose health risks in their unmodified forms or those emitted directly from identifiable sources. Secondary air pollutants - Primary pollutants interact with one another, sunlight, or natural gases to produce new, harmful compounds