期刊名称：International Journal of Educational Research and Technology
印刷版ISSN：0976-4089
出版年度：2012
卷号：3
期号：3
页码：83-85
出版社：Society of Education
摘要：The term pollution is used to describe the introduction of harmful substances into the environment as a result of domestic, agricultural or industrial activities.Substances which pollute the air include gases like oxides of carbon, sulphur and nitrogen and the hydrocarbons emitted by thermal plants, motor vehicles and chemical industries. The increase in the level of carbon dioxide produces greenhouse effect, while nitrogen and sulphur oxides come down as acid rain causing destruction of vegetation and aquatic life. Water is normally polluted by effluents from industries, pesticides and fertilizers washed down from agricultural fields and city sewage. The greatest release of hazardous waste to the environment is from industries. Toxic chemicals flowing into rivers often kill fish. People who eat the contaminated fish have been known to develop health related problems, at times even fatal. Oil spills are also a major cause of water pollution which, if happens near the shore may seriously affect coastal flora and fauna. The increasing level of noise is also another cause of pollution which affectsthe environment. Pollution in any form is harmful to human life, and unless checked in time may threaten our very survival.Environmental pollution caused by the use of solvents, reagents and products will be dealt herewith. The solvents that are mostly employed include volatile organic solvents (VOCs) like methylene chloride, chloroform, perchloroethylene and carbon tetrachloride. Some VOCs like, isopropyl alcohols, xylenes toluenes and ethylenes have been used as cleaning fluids because of their ability to dissolve oils, waxes and greases.Also, they readily evaporate from the items that they are being used to clean (VOCs readily evaporate or vaporise at room temperature). When VOCs come in contact with sun light and nitrogen oxides (by-products from the combustion of fossil fuels), these are transformed into ozone, nitric acid and partially oxidised organic compounds(Baird, 1999).VOCs + NO Sunlight O3+ HNO3+ Organic Compounds (Partially Oxidised)This product mixture is formed at the ground level and is commonly called smog. Continued exposure to smog may result in aggravating asthma and may induce respiratory problems1and can also cause lung cancer.This phenomenon leads to elevated levels of tropospheric ozone (one of the components of smog) and may cause damage to crops, discolour fabrics and harden rubber
