Pollution associated with the urban development result in a spectrum of chemical and biological changes in our environment. Environment is composed of air, water and soil. These are inter- connected.
Anything discharged into one compartment (air, water or soil may find its way into other compartments as well.
Air pollution may be defined as any atmosphere condition in which certain substances are present which are not naturally present or which are present in such concentration and of such duration as may be hazardous to humans, plants, animals etc or property.
Contaminants of the air are smoke, vapours, gases, mist, odours, particulate matter, radioactive substances or undesirable chemicals or any other type of substance in the atmosphere.
These are broad definitions usually used in writing legal statutes.
Air pollution caused by large power plants, mines and other industries is not problem of that particular locality only. It affects both remote as well as nearby ecosystems. One of the worst aspects of air pollution is that pollutants or contaminants released into air in one country may affect people in another country. For example, polluted air from England and Central Europe causes acid rains in Scandinavian countries. Hence air pollution can be considered as ‘transformer pollution’.
Causes and Effects of Air Pollution
A man consumes or inhales around 25 kg of air a day. This is several times the amount of food that an average human being consumes per day i.e, 1.5 kg. This underscores the importance of air pollution control.
The atmosphere in a particular locality is a dynamic system. A large number of pollutants will be present at any given time. The atmosphere steadily absorbs various pollutants and thus forms a natural sink. If the pollutants enter inside the atmosphere at a faster rate rather than at which they are absorbed by the natural sinks, the pollutants concentration gradually builds up. This results in pollution of the air.
The causes for such a built up of concentrations of contaminants are many.
- Growth in Population
With an increase in the population the absolute minimum requirements of commercial energy has increased too. India occupies 2.5 % of the land area of the world. But it caters to about 20% of the world population.
2. Development of Energy Sources
The per capita consumption of energy has also gone up steeply with the advent of industrialization. The discovery and the development of fossil fuel such as coal and petroleum have contributed a lot to increases in the per capita consumption of energy. Tapping of hydroelectric energy and nuclear energy may also lead to environmental, technological and sociological problems.
3. Urbanization
Urban areas witness a very high rate in growth of population. The number of motor vehicles and the factories which require fossil fuels are also more. So the problems of air pollution are more acute in urban than in rural.
4. Use of Chemicals
Newer and newer chemicals are being developed, manufactured and used by moder factories. Proper toxicological information regarding many of these chemicals are not available. Even though their concentrations in the atmosphere are quite small it is quite possible that they may affect the health of living beings.
Indiscriminate use of some chemicals such as nitrate fertilizers and refrigerants are responsible for depleting the ozone layer considerably
The effects of air pollution are manifold. The few of these are :
- Reduction in the visibility –Photochemical smog.
- Climate is affected –Fog formation decreases the solar radiation by 15.20%.
- Weather is also affected-ambient temperature rises.
- May cause irritation to eyes and skin.
- The respiratory system may be affected.
- Emission of radiation during the processing of nuclear fuels and other carcinogens may cause cancer.
- Rise in the concentrations of toxic chemicals (due to accidents will led to death.
- Aerosols of fertilizers sprays enter the food and fodder causing several unknown diseases to man and cattle.
- The life of buildings and other structures may be shortened by acid rains.
The life to which the pollutants cause the damage to living beings or materials depend on their concentrations and their persistence in the atmosphere.