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Occupational exposure limits are the maximum allowable concentrations of hazardous elements in the air. They are defined by scientific laboratories in order to control the level of pollution in different areas. Among the main atmosphere pollutants are large-scale industry, domestic boilers and transport. The portion of each of these pollutants is different from place to place, but industrial companies are considered to be the worst pollutants. The major sources of artificial aerosol pollution of the atmosphere are thermal power plants that burn a large amount of coal with high ash content, concentrating mills, metallurgical, cement, magnesite and soot plants. |
Heat pollution
Heat pollution of the water reservoir surfaces and coastal water areas in seas is the result of dumping of heated waste waters by power plants and some industrial manufacturers into the water reservoirs. The dumping of heated waters in many cases causes the increase in temperature of water in such reservoirs or areas for 6-8 degrees Celsius. The increase of the water temperature in separated areas leads to changes in chemical and biological parameters of the medium by decreasing the oxygen content, access of sunlight to aquatic plants, and increases the toxicity of polluting agents and the speed of growth of harmful seaweed. The areas of such heated waters in coastal areas can reach 30 square kilometers. More steady temperature stratification prevents water exchange between the surface and bottom layers. The oxygen dissolubility is decreased and its consumption increases due to the fact that together with the rise in temperature the activity of aerobic bacteria decomposing the organic substance. The species diversity of phytoplankton and the whole flora of seaweeds intensifies.
It is notable that the Intergovernmental Panel on Climate Change has stated that the effect of heat pollution on the whole ecological situation on earth is insignificant in relation to the greenhouse effect. There is not many disputes about heat pollution as a serious cause for concern today largely because the amount of heat that the human is able to produce is still comparatively small. But at the same time the high rates of growth of such pollution are not taken into account.
