Pollution is the undesirable change in the physical, chemical and biological characteristics of the environment which adversely affects the biotic community (plants, animals, and human).
The pollutants are the materials that cause pollution in the environment. The common pollutants noticed in developed and developing countries are;
Deposited matter-Smoke, Dust, Sand, Plastics, Glasses, etc.
Chemical compounds- Phosgene, Detergents, Aldehydes, Hydrogen fluorides etc.
Poisons- Fungicides, Pesticides, Insecticides, Herbicides etc.
Pollutants can be classified into two basic types:
- Non-degradable pollutants
- Degradable pollutants
The pollutants which do not degrade or decompose naturally and remain in the natural atmosphere for a long time are called non-degradable pollutants. Eg: glasses, plastics, DDT etc.
The pollutants that are decomposed easily by natural processes are called degradable pollutants. Eg: Domestic sewage, fertilizers etc.
An undesirable change in the physical, chemical or biological characteristics of air is called air pollution. The substances which pollute the air is called pollutants.
Causes of air Pollution
Different gases, dust, smoke, disposed wastes, and garbage, etc. are pollutants. These substances make the pollution in the air and the air mixed with these substances is called polluted air. The air pollution may be caused by natural process or by human activities.
- Air pollution caused by natural process
Some of the natural process which causes air pollution are: Gases and particulate matter released along with lava from the volcanic eruption, the dust raised from the ground during strong winds and storms, smoke from forest fires and fog. The finely divided solid or liquid particles suspended in the air called particulate matter i.e. dust, smoke, fumes. Apart from these, decomposition of plant and animal remains and pollen grains also cause air pollution.
- Air pollution caused by human activities
- Mixing of smoke in the air: People burns fuels like coal and petroleum products to obtain heat and electric devices and to transport vehicles. All these produces a lot of smoke. The smoke emitted by various sources like a kitchen, factories, airplanes, explosive materials, vehicles, acid rain, carbon monoxide, firewood, etc. are very harmful to human beings and pollute the air badly. It destroys vegetation and crop plants. It also stops the growth of plants.
- Mixing of dust particles in the air: The small particles which are fixed in the air is called dust. It is another factor which causes air pollution. Dust particles, if inhaled, various allergic reactions occurs in the human body. They may cause diseases like bronchial asthma and other lung diseases. Polluted air contains lead particles which are very poisonous substance. It reaches into a human body by respiration and keeps on accumulating in the tissues of the human body. It causes mental disorder and muscular paralysis and abnormalities in pregnancy.
- Mixing of bad odor (smell) in the air: The deposit of organic wastes also cause pollution in the air. Due to improper management of clearing system, dumping site and leaking sewage, solid wastes and pollution are increasing day by day. The gas produces from the organic solid wastes and participate matters are sulphur dioxide (SO), nitrogen dioxide (NO) and carbon (C). These gases mix with air and pollute the air and the whole environment as well. Sulphur dioxide causes lung diseases in human beings such as bronchitis.
Effects of Air pollution
- Air pollution causes respiratory tract infection (RTI) and asthma.
- It deteriorates the cultural heritage and trees.
- It brings various skin and eye allergy.
- It is the main causes of global warming
Preventive measures of air pollution
- The air pollutants should be controlled as the point source by using electrostatic precipitator or filter in the industries.
- The use of cheap fuel with higher sulphur content should be avoided. Use of desulfurized coal should be used.
- Alternate sources of energy should be used in place of coal, wood, oil etc.
- Population growth rate should be controlled.
- Strip plantation should be done everywhere on the roadside.
- A strict check of car exhaust should be maintained.
- Public awareness programme on the effects of pollution should be managed.