Air Pollutions Chemistry Essay

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Air pollutions The atmosphere is the layer of gas around Earth. Because of gravity, the gas is at its most dense at sea level, forming the mixture we call air. Pure air contains about 78% nitrogen (N), 21% oxygen (O2),1.0% argon (Ar),0.03% carbon dioxide (CO2), and trace amounts of other gases together with up to 4% water vapour. Atmospheric pollution (also commonly called air pollution) is one or more chemicals, substances, or physical conditions (such as excess heat or noise) in high enough concentrations in the air to harm humans, other animals, vegetation, or materials. An air pollutant can be described as a substance that is not normally present in air or a substance that is normally present but in excess amounts. The main primary air pollutants are carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), particulates (like: soot, ash, dust, asbestos, smoke), and hydrocarbons (CxHy or R-H). Secondary pollutants are compounds formed when primary pollutants react in the air. The sources of air pollution are both natural and human-based. As one might expect, humans have been producing increasing amounts of pollution as time has progressed, and they now account for the majority of pollutants released into the air. Natural sources of pollution are often much greater than their man-made counterparts. Natural sources of SO2, include release from volcanoes, biological decay and forest fires. Actual amounts released from natural sources in the world are difficult to quantify. In 1983 the United Nations Environment Programme estimated a figure of between 80 million and 288 million tonnes SO2 of per year (compared to around 69 million tonnes from human sources world-wide). Natural sources of NOx, include volcanoes, oceans, biological decay and lightning strikes. Estimates range between 20 million and 90 million tonnes per year NOx,
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