NCERT Solutions for Class 8 Science Pollution of Air and Water
Class 8 Science : In this article, we have discussed ‘Air pollution, its pollutants and effects’ from ‘Pollution of Air and Water’ of Class 8 Science.
The air around us is a mixture of many gases and dust particle. The percentages of the major gases present in air are-
- Nitrogen (78.08%)
- Oxygen (20.95%)
- Carbon dioxide (0.03%)
- Other gases (0.97%)
Air pollution is basically the occurrence of the chemical in the air in quantities which are harmful to human health and the environment.
The common air pollutants and their main sources:-
- Particulate Matter: – It is made up of tiny particles suspended in air. Major particulate matter sources are volcanic eruption, dust storm, burning of fossil fuel in thermal plants and forest fire. They are also present in exhaust fumes of automobiles and power plants as soot, fly ash and lead particles.
- Chlorofluorocarbons (CFCs) – They are commonly used as coolants in refrigerators, air conditioners and as propellants in aerosol spray cans. They are also used in home insulation, plastic foam, and throwaway metallic cans.
- Burning of fossil fuels- They are coal and petroleum in thermal power plants and automobile releases oxides of sulphur and nitrogen into the air.
- Burning of carbon– Carbon-rich fuels such as firewood, coal, and petroleum releases carbon dioxide and carbon monoxide into the atmosphere.
Watch interesting videos and learn causes of air pollution with CBSE Class 8 Science.
The effects of air pollution
- Global warming– An increase in the concentration of carbon dioxide in the atmosphere is one of the major causes of air pollution. It refers to the unnatural increase in the earth’s surface temperature. We believe that increase in the amount of carbon dioxide and certain other gases is responsible for phenomena called Global warming.
- The trapping of solar radiation by the earth’s atmosphere because of the presence of gases such as carbon dioxide, water vapor, and methane is called the greenhouse effect. Without the natural greenhouse effect, the earth’s surface would have been too cold to sustain a life. The increase in the amount of greenhouse gases beyond natural limits is a cause of worry.
Watch an interesting video on the greenhouse effect, learn and understand how it effects, click CBSE Class 8 Science for details.
The causes and possible effect of global warming are as below:-
- Deforestation- it increases the earth’s surface temperature.
- Burning of fossil fuels-it leads to melting of polar ice caps.
- The release of methane due to the breakdown of organic matter-it leads to rise in global sea level resulting in flooding of low lying coastal regions.
Watch the other effects of air pollution and water pollution and we will discuss in the forthcoming article.
In 8th Class Science – You can read another notes, NCERT Solutions for Class 8 Science
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