AP 8th Class Biology Notes Chapter 7 Pollution of Air and Water
→ Air Pollution : If solid, liquid and gaseous substances are present in higher volumes than required in the air, it is harmful to air. It is called air pollution.
→ Chemical Contamination : Discharge of harmful chemicals into rivers and streams causing pollution of water is called chemical contaminator.
→ Global Warming : CO2 traps the heat and does not allow it to escape into space. As a result, the average temperature of earth’s atmosphere is gradually rising. This is called global warming.
→ Greenhouse Effect : The trapping of radiations by the earth’s atmosphere is called the greenhouse effect.
→ Pollutants : The substances which contaminate air and water are called pollutants.
→ Potable Water : The water which is purified and fit for drinking.
→ Water Pollution : The contamination of water by those substances which are harmful to life.
→ Air consists of a mixture of gases. 78% of this mixture is nitrogen and about 21% is oxygen. Carbondioxide,argon, methane, ozone and water vapour are also present in very small quantities.
→ When this balanced state is disturbed either by some natural phenomena or by human activities, it is called “Air Pollution”.
→ Volcanic eruptions, forest fires, sand storms etc ….are natural causes of air pollution.
→ Smoke from factories, automobiles, burning of fire wood etc. …..are man made causes of air pollution.
→ Pollutants are the substances which contaminate air and water.
→ Carbon monoxide (CO), nitrogen oxides, carbondioxide, methane and sulphur dioxide are the major pollutants of air.
→ Increasing levels of greenhouse gases like CO2, methane and water vapour leading to global warming.
→ Water pollution is the contamination of water by substances harmful to life.
→ Sewage, agricultural chemicals and industrial wastes are some of the major contaminants of water.
→ Ganda Action plan (1985) and National Mission for Clean Gang (2016) are aimed to reduce the pollution levels in the river Gaga.
→ Water which is purified and fit for drinking is known as potable water.
→ Water is a precious natural resource. We must learn to conserve it.
We should consciously save water and not waste it. Reuse, Reduce and Recycle should be our main mantra.
→ Unless we all realise our responsibility and start using environmental friendly processes the very survival of our planet is in danger.