Air Pollution , causes , effects , prevention
Pollution may be defined as the undesirable change in the physical, chemical or biological aspects of environment which makes it harmful for humans and for others living – organisms. There are various types of pollution such as air pollution, water pollution, noise pollution.
The context of the recent condition of Delhi was an extremely hazardous issue. Air pollution refers to the degr-adation or deterioration in the quality of air called air pollution. It is the release into the atmosphere of mate-rials in concentrations that are harmful to man, other animals, plants and other biotic and biotic objects.
Causes of Air Pollution
There are two main causes of Air pollution are :-
1. Nature Activities
Volcanic eruptions, earthquakes, dust, storms, Forest fire, etc. releases harm-ful gases and hence cause air poll-ution.
2. Human Activities
- Use of fertilizers pesticides in agricultural field pollutes the air.
- Burning of fossils fuels.
- Thermal power plants pollute air by emitting sulphur dioxide and fly- ash.
- Industries pollute air by relea-sing various types of pollutants such as SO2, Oxides of carbon, Nitrogen oxide, etc.
- Deforestation leads to decre-ment in the density of trees in jungles and hence causing ano-ther CO2 menace.
- Use of CFCs in refrigeration, fire extinguishers and aerosal sprays pollute air by depleting the ozone layer.
Effects of Air Pollution
- Air pollution affects respiratory system causing breathing difficulties and diseases such as asthma, lung cancer, bronchitis & pneumonia.
- Lead affects central nervous system.
- Air pollution causes depletion of ozone layer due to which UV-rays can reach the earth and causes skin cancer, damage eyes and immune system.
- It causes acid rain, which dama-ges crop, plants, trees, building, monuments, statues, etc.
- It causes greenhouse effect or global warming which leads to excessive heating of earth, s atmosphere. Due to global war-ming, ice will melt, hence the sea level will rise and would cause floods.
- Pesticides like DDT which are toxic in nature can enter into food and get accumulated in the body causing kidney disorders and mental problems.
Prevention and Control
- Dilution of emission can be acc-omplished by using the tall chi-mneys or stacks. High chimneys can be useful in preventing the pollution to dwell at ground level.
- Air pollution filtering at source:
- The air pollution problems can be reduced at the source by adopting the following:-
- Substituting the raw material.
- Modification of process:- It invol-ves new techniques with lower-ing atmosphere pollutants. e. g. Double catalyst double absorber (DCDA) process was developed to reduce SO2 emission in stack gases.
- Equipment alternations:- Such as the floating roof tanks rather than vented tank can cut down on the evaporation losses.