Air – It is mainly a mixture of two gases – Nitrogen and Oxygen which is colorless, tasteless, and invisible. Air is an extremely important natural resource, which is essential for all living things due to all the living things breathe in air and exists life on the earth.
If the air is polluted with several poisonous gases or chemicals then it is very harmful to the health of human beings, plants and animals.
Air Pollution – An undesirable change in the physical, chemical, or biological characteristics of air is known as air pollution. The substances which pollute the air are called pollutants. The pollution of air may be caused by natural processes or by human activities are as discussed below –
- Air Pollution due to Natural Processes – Some of the natural causes of air pollution such as smoke from forest fires and fog, gases and particulate matter released along with lava from volcanic eruptions, the dust raised from the ground during strong winds and storms. Apart from these, methane gas is produced by bogs (marshy areas), the decomposition of plant and animal remains, and the pollen grains also contribute to air pollution. The contribution of these natural pollutants in the pollution of air is very small and within the tolerance limit of human beings. Therefore, the effects of air pollution produced by natural processes on human beings are negligible.
- Air Pollution due to Human Activities – Man burns fuel such as coal and petroleum products to obtain heat and electric power and run to transport vehicles. The burning of these fuels produces a lot of smoke. The main cause of air pollution is the smoke emitted by various sources. The smoke is emitted into the air by the kitchen, automobiles, airplanes, factories, thermal power stations, and railway engines due to which the air gets filled with carbon monoxide, dust, and carbon dioxide. In some places, the pollutants like oxides of sulphur, chlorine, ammonia, benzene, lead particles, oxides of nitrogen, and chloro-fluoro-carbons (CFCs) are also present in the air (Chloro-fluoro-carbons are used in refrigerators).
Air pollution has an adverse effect on the life of human beings, animals, and plants. Air pollution also affects raw materials, industrial processes, living conditions, and cultural assets such as historical monuments and spoils them.