Received date: 01 November, 2012; Accepted date: 25 December, 2012
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Air pollution can have serious costs, penalties and consequences for the health of human beings and also ruthlessly distresses the natural bio-network and ecosystems. The main consequences of air pollution are global warming, acid rain, smog, ozone depletion etc. India ranks 13th most polluted country with an annual mean of 109 μg/m3 of PM10. China contributes 21.5% of the total CO2 emission followed by U.S. (20.2%), Russia (5.5%) and India (5.3%). On a larger scale, government is taking measures to limit emissions of carbon dioxide and other greenhouse gases to protect the quality of environment. According to W.H.O. report air pollution causes about 2 million premature deaths worldwide per year. The Clean Air Act is a superb representation of the government’s role in air pollution prevention. It aids to influence and enforce laws that attempt to eliminate or dilute the causes of air pollution. This paper deals with the causes, effects, present status and the remedial measures to counter the existing problem of air pollution, so as to create quality atmosphere in existence.
Particulate Matter, Ecosystem, Global Warming, Smog, Industrialization.
Environmental degradation has increased over the last several decades. Vehicular emissions, rapid industrialization and urbanization are the main sources of air pollution. A compelling reason for controlling air pollutants, such as suspended particulate matter (SPM), respirable particulate matter (RPM) and sulphur dioxide (SO2) is their damaging effect on human health. Of all air pollution constituents, the WHO has identified SPM as the most sinister in terms of its effect on health (Singh et al. 2009). India stands third (after china and US) among the countries with highest CO2 emissions, with annual CO2 emission estimate of 2,069,738 (in thousands of CO2 metric tons). As the World Health Organization (WHO) points out, outdoor air pollution contributes as much as 0.6 to 1.4 percent of the burden of disease in developing regions, and other pollution, such as lead in water, air, and soil, may contribute 0.9 percent (WHO, 2002). Central Pollution Control Board is executing a nation-wide program of ambient air quality monitoring known as National Air Quality Monitoring Programme (NAMP), covering one hundred and twenty one (121) cities/towns in twenty five (25) states and four (4) Union Territories of the country. Under this program, three criteria air pollutants (SPM, SO2 and NO2) have been identified for regular monitoring at 290 stations spread across the country. Values are different depending on the area whether industrial or residential or areas with high traffic density like traffic intersection (CDIAC: Record High 2010). This paper deals with the causes, effects, present status and the remedial measures to counter the existing problem of air pollution, so as to create quality atmosphere in existence. The various categories of air pollutants and their harmful effects are summarized in the given Table.
• Global warming: According to estimates, at the current rate of increase, the average global temperature up by 3°C to 8°C in the next 100 years. This will affect the climate of different regions, distribution of plants and animals, disturbance in agriculture and food production, melting of snow caps and resultant increase in sea levels. This will submerge parts of coastal cities of Calcutta, New York, London and other major cities.
• Formation of photochemical smog: When pollutants like hydrocarbons and nitrogen oxides combine in the presence of sunlight, smog is formed. This is a mixture of gases and since it is formed by photochemical reactions, it is called the photochemical smog. The word ‘smog’ is derived from the two words-smoke and fog. It forms a yellowish brown haze especially during winter and hampers visibility. It also causes many respiratory disorders and allergies as it contains polluting gases.
• Formation of acid rain: Sulphur dioxide and nitrogen oxides react with water in the atmosphere producing sulphuric acid and nitric acid. These acids come down along with the rain. This phenomenon is called acid rain. The pH of acid rain varies from 3-6. The composition of acid rain is sulphuric acid, nitric acid and weak carbonic acid. Its adverse affects on the environment include: causes respiratory and skin disorders, affects productivity of plants by damaging the leaves, enters the soil and affects the soil, pH and causes leaching, enters the ground and river waters which causes harm to the aquatic life, causes damage to marble and thus damages buildings and monuments (like Taj Mahal).
• Aerosol formation: Aerosol is formed by the dispersion of solid or liquid matter in the atmosphere. If the aerosols form a thick layer in the troposphere, they affect the weather conditions by blocking the solar radiation. Aerosols are also deposited on the leaves and affect the photosynthesis. Aerosols disperse the organic metallic pollutants far and wide.
• Depletion of Ozone: The stratosphere of the atmosphere has ozone (O3). Ozone is known to absorb the Ultraviolet (UV) rays present in the sun’s radiation and protects us from the harmful effects of the UV rays. However, hydrocarbons such as the chlorofluorocarbons (CFCs) destroy the ozone molecules which deplete the ozone layer. Ozone holes have been detected in the atmosphere which permits the UV rays to reach the earth’s surface. The harmful effects of the UV rays are visible in the countries such as Australia and New Zealand where the rate of skin cancer is higher than the other regions of the world (www.tutorvista.com).
Technologies to reduce air pollution at the source are well established and should be used in all new industrial development. Retrofitting of existing industries and power plants is also worthwhile. Various emission standards have been set for automobiles (Bharat stages-2, 3 and 4). On global scale, the UNCED, Earth Summit (1992) established principles for reducing GHG emission. The Kyoto Protocol (1997) aimed at achieving GHG emissions below 5% till 2012, followed by Copenhagen summit, 2009 & recent in 2011 at Durban to keep the process in run. The principles and practices of sustainable development, coupled with local research, will help contain or eliminate health risks resulting from air pollution. International collaboration involving both governmental and nongovernmental organizations or can guide this highly interdisciplinary and intersectional area of pollution control.