Essay On Environmental Pollution

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1 INTRODUCTION Environmental pollution is one of the worldwide growing threats to human health and natural resources. One major cause of environmental degradation is air pollution due to natural and manmade sources. The main impacts of air contaminants include ground- level ozone, acid rains, greenhouse effect, climate change, ozone layer depletion and adverse health hazards. Benzene and toluene are organic compounds found in indoor air as a result of emissions from burning coal and oil, some household products which contain petroleum based chemicals like glues, paints, etc. Outdoor sources are like gasoline vapors at gasoline service stations, motor vehicle exhaust, emissions from industrial sources utilizing benzene and toluene, etc. Both benzene and toluene are harmful for human health as they cause damage to central nervous system, dysfunction, narcosis, tremors and death. Benzene and toluene are also carcinogenic in nature. Biofilters have been used for removing hazardous substances such as toluene, chlorinated hydrocarbons, and the mixtures of benzene, toluene, ethylbenzene, and xylenes (BTEX) from gas streams (Leson and Winer 1991). In biofiltration polluted air containing odorous gases is passed through a porous media that may be wood chips, soil or compost or mixture of above that support microorganisms. Under the optimum conditions, the microorganisms degrade the organic contaminants by converting them into carbon dioxide (CO2), salts and microbial biomass. Zilli
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