Air Quality in Rural Areas

Abstract

The immediate environment of man comprises of air on which depends all forms of life. Human beings need a continuous supply of air to exist. The requirement for air is relatively constant about 10-20m3 per day (Park 2009). Air is a mechanical mixture of gases. The normal composition of external air by volume is approximately as follows Nitrogen 78.1%, Oxygen 20.93%, and Carbon dioxide 0.03%. The balance is made up of other gases which occur in traces e.g. argon, neon, krypton, xenon and helium. In addition to these gases, air also contains water vapor, traces of ammonia and suspended particulate matter such as dust bacteria, spores and vegetable debris. The external air has other compounds and elements along with the already mentioned. Air is rendered impure by a) respiration of man and animals b) decomposition of organic matter, c) combustion of coal, gas, oil etc. d) trade, traffic and manufacturing processes that give off dust, fumes vapors and gases. Under ordinary conditions the composition of outdoor air is remarkably constant. This brought about by certain self cleansing mechanisms which operate in nature such as wind, sunlight, rain and plant life. Wind dilutes and sweeps away the impurities by its movements so that the impurities do not accumulate in any one place. Sunlight and heat oxidizes the impurities and kill the bacteria. Rain removes the suspended and gaseous impurities and the green plants utilize the carbon dioxide and generate oxygen. But when the rate of pollution becomes too high or the cleansing process becomes ineffective, the air gets polluted and it constitutes a health hazard. Human occupancy and activity vitiate the air in the occupied rooms and gives a sense of discomfort to the occupants. Unless the vitiated in door air is replaced by the fresh air, it may adversely effect the comfort, health and the efficiency of the occupants. They may feel suffocation and complain of headache, drowsiness and inability to concentrate. There is also a risk of droplet infection and lowered resistance to diseases on prolonged exposure. Thus the phenomenon called pollution is an inseparable consequence of the presence of man and his activities. The term air pollution signifies the presence in the ambient atmosphere of substances (e.g., gases, mixtures of gases and particulate matter) generated by the activities of man in concentrations that interfere with human health, safety or comfort, or injurious to vegetation and animals and other environmental media resulting in chemicals entering in the food chain or being present in drinking water and thereby constituting additional source of human exposure. The direct effect of air pollutants on plants, animals and soil can influence the structure and function of ecosystems, including self regulation ability, thereby affecting the quality of life (WHO 1987).