1.4.1. Air Pollution

Air pollution is the introduction of chemicals, particulates, biological materials or other harmful materials into the earth’s atmosphere. These pollutants can be solid particles, liquid, and gases. Major pollutants are carbon oxides (COx), Nitrous Oxides (NOx), Volatile organic compounds, particulates, sulphur dioxide, Toxic metals such as lead and mercury etc. Many of these are new compounds in the atmosphere which have changed the composition to negligible level but their presence throws challenges for humans. It causes damage, disease and death of humans and other living organisms or infrastructure. Air pollution causes respiratory infections, heart disease, and lung cancer etc. Major sources of these pollutants involves vehicular emission, power plants, industries, waste incinerators, agricultural practices, fumes, waste deposition etc.

Acid rain is the result of increased pollutants in the atmosphere. Rain water is naturally acidic due to atmospheric carbon dioxide which makes weak acid with rain water. Acid rain is caused by other gases released when fossil fuels are burnt. Two gases are the main culprits: Sulphur dioxide (forms sulphuric acid) and Nitrogen oxides (forms nitric acid). These increase the acidity of rainwater. The dilute acid falls to ground as acid rain which causes the following problems:

♤ Lakes become acidic and plants and fishes die as a result

♤ Tree growth is damaged, whole forests can die as a result

♤ Acid rain attacks metal structures and also buildings made of limestone