Environment - Air Pollution
Environment - Air Pollution
Air not only supports the human life but is also essential for the survival of plants and other animals. Polluted air can cause many disease such as cancer and lung malfunctioning. The main pollutants of air are the smoke, dust, ash, pollengrians, poisonous gases and tiny particles of materials. The air pollution is mainly caused by burning fossil fuels like coal, petrol, natural gas etc. industrial plants, electric plants and automobile engines also add to air pollution. They produce oxides of nitrogen, sulphur dioxide, carbon monoxide particulate matter etc. and pollute the air. The smoke emitted by factories, automobiles, trains, ships etc. also release poisonous particles in the air. The smoke of jet planes pollutes the upper atmosphere. Air pollution causes many diseases like allergy, cough, cold, heart troubles asthma and many types of cancers. Green leaves turn yellow due to air pollution. The growth of the plants is slowed down. The paint of the buildings gets faded and the colors of various materials and clothes get bleached due to air pollution.
The increasing quantity of carbon dioxide has posed a serious threat to the environment. Prior to industrial revolution the amount of carbon dioxide was 275 to 285 parts per million in the atmosphere. By 1980s this increased to 338 parts per million.
In the beginning of the 21st century, this has further increased to 400 parts. The heat energy radiated from the earth is in the form of long waves. About 90% of this heat is absorbed by the atmosphere. Atmosphere heats up mainly due to this terrestrial radiation. The complete absorption of terrestrial radiation and noncapturance of solar radiation by the atmosphere is called green house effect. The green house effect was explained for the first time by the Swedish chemist Arrhenius in 1986. In a green house, the glass walls and roof allow the sunlight to reach the earth but they do not allow the terrestrial radiation to go out. This causes the temperature to rise.
On the global scale, carbon dioxide in the atmosphere acts as a green house. The carbon dioxide is largely transparent to incoming light energy but outgoing infrared radiation from the earth is absorbed by carbon dioxide leading to a warming of atmosphere. If the amount of carbon dioxide continues to increase in the atmosphere then the atmospheric temperature will become so high that ice of Polar Regions will melt and water level in oceans will rise, leading to flooding of coastal areas. The air pollution also affects direction of wind, temperature, climate and weather. Air pollution is adversely affecting the historical monuments. The Taj Mahal of Agra is being adversely affected by the smoke emitted by the petroleum refinery situated in Mathura. The capital city of Japan, Tokyo, is the world’s most polluted city.
Air pollution can be controlled to a large extent by planting more and more trees and by fitting electrostatic filters in the chimneys of the factories that emit the smoke hazardous to the environment.