This PSEB 8th Class Science Notes Chapter 18 Pollution of Air and Water will help you in revision during exams.
PSEB 8th Class Science Notes Chapter 18 Pollution of Air and Water
→ Undesirable change in the physical, chemical, and biological characteristics of air, water, and land, that may harmfully affect human life and other living organisms is termed pollution.
→ The agents or substances which cause pollution of air, water, and land, are called pollutants.
→ Types of Pollution:
- Air pollution
- Water pollution
- Noise pollution
- Soil pollution
→ Air Pollution is the occurrence of or addition of particulate matter, gases, and other pollutants into the air, which can be harmful to human beings, animals, vegetation, buildings, and other assets.
→ Water Pollution is the addition of organic, inorganic, biological, or radiological substances or factors like heat in water which degrades its quality so that it becomes a health hazard and unfit for use.
→ Water pollution is a serious health hazard in India, especially in villages.
→ Ozone depletion has resulted in UV radiations reaching the earth and causes skin cancer, damage to eyes, and defense mechanisms. Acid rain is the result of air pollution.
→ Global warming is due to the slow rise in the earth’s temperature due to an increase in CO2 concentration in the atmosphere.
→ Global warming can be stopped by cutting down the use of fossil fuels and by reforestation.
→ Industrial processes lead to pollution, this pollution can be controlled and prevented.
→ The heating up of the earth’s atmosphere due to the trapping of infrared radiations by carbon dioxide in the atmosphere is called the greenhouse effect.
→ The main gases present in the air are nitrogen and oxygen.
→ The various gases present in the air are nitrogen, oxygen, carbon dioxide, argon, helium, krypton and xenon, water vapours.
→ Air contains 78% by volume of N2 and 21% by volume of O2.
→ Air Pollution: We can define air pollution as the introduction into the atmosphere of materials more than the required amount that will produce or contribute to an adverse effect on the health and well-being of man. Air pollution is not only a general nuisance, but it is also a hazard to the health of plants, animals, and the man himself.
→ Contamination: It is the presence of harmful substances or micro-organisms that may cause disease or discomfort to human beings.
→ Pollution: It is defined as the addition of extraneous constituents to water, air, or land, which adversely affects the natural quality of the environment. Polluted material need not necessarily be contaminated.