Explain the differences between pure air and polluted air

Pure air is a mixture of several gases that are invisible and odorless. It consists about 78% nitrogen, 21% is oxygen and less than 1% of Carbon dioxide and other gases like argon, methane and ozone and varying amount of water vapors. Polluted air on the other hand, is contaminated with the substances like smoke, dust and other harmful substances called pollutants. These pollutants can come from natural sources like smoke and dust arising from forest fires or volcanic eruptions. Pollutants can also be added from the human activities. The sources of air pollution are automobile exhausts, power plants, factories and burning of firewood and dung cakes.

Pure air contains around 78% nitrogen, 21% oxygen, and 0.03% carbon dioxide. Other gases such as argon, methane, ozone, and water vapours are also present in small quantities. When this composition of air is altered by the addition of harmful substances or gases such as nitrogen dioxide, sulphur dioxide, carbon monoxide, and particulate matter, then the air is said to be polluted

Pure air Polluted air 1. Pure air contains around 78% nitrogen, 21% oxygen and 0.03% carbon dioxide. 1. Polluted air has no such definite composition of these gases. 2. Other gases such as argon, methane, ozone, and water vapours are also present in small quantities. 2. Polluted air has harmful gases like nitrogen dioxide, sulphur dioxide, carbon monoxide, particulate matter etc. 3. It is fresh and healthy for lungs. 3. It can cause respiratory diseases.

- Hint: The pure air consists of the right amount of gases that is 78% nitrogen, 21% oxygen and less than 1% of argon and carbon-dioxide and other gases whereas polluted gases do not requisite proportion of gases and there is presence of unwanted substances. Complete step-by-step solution - The constituent gases are present in the balanced quantity in pure air. Pure air has 78% nitrogen, 21% is oxygen and carbon dioxide, argon, methane, ozone and water vapour are also present in very small quantities. It is also free from harmful gases and is fit for breathing. On the other hand polluted air has undesirable particles and gases and other suspended impurities like dust and smoke. It is unfit for breathing and has a harmful effect on lungs of the humans and also the non-living objects. Here, the major air pollutant and their sources and effects are mentioned in the table: Major Pollution of Air Some of the Sources Some of the effects $\text$ Vehicular combustion and burning of fuels and hydrocarbons Global warming, green house effect, CO has great affinity for haemoglobin and forms the caboxyhaemoglobin Smoke, fly ash and soot Thermal power station Respiratory diseases CFCs Refrigerants and aerosol Kidney damage and ozone depletion Note: We should know that increased human activity releases a large amount of pollutants to the environment and poses a threat to human life. Pollutants that are added to the environment through human activities are termed anthropogenic pollutants.