Like soil air is also polluted by natural or human activities. Air is polluted by natural causes like sandstorm, forest fire, volcanic eruption etc. Dusts, smoke and poisonous gases mix with air and make the air polluted. Air is being polluted by smoke from mills and factories, automobiles and from bad smell of waste materials. In the smoke of industries and automobiles there are CO2, CO, SO2 and various other harmful gases. What will happen if the concentration of CO2 increases in the air? The effect resulting the increase of CO2 in the atmosphere is known as Green House Effect.
As a result of green house effect the temperature of the atmosphere increases. For this, there is a possibility of dissolving the ice of polar region and that may cause great flood. Many seaside and low-lying countries will be submerged.
When carbon monoxide mixes with blood, it totally destroys the Oxygen transport capacity of blood. Without Oxygen people will die. Sulphur dioxide and Nitric oxide, produced by Nitrogenous fertilizers, when mixed with rainwater causes acid rain, which is very much harmful for plants, animals, buildings, and instruments. CFC (Chloro-Fluoro Carbon) gas evolves from various materials used by human beings gets in the atmosphere. CFC gas is responsible for damages in the Ozone layer. Detailed discussion in this respect will come later. The most effective way to stop air pollution is to increase the number of plants. This will maintain the balance of the amount of O2 and CO2. On the other hand it is necessary to take care so that no harmful gas can be mixed with the air. Condition will improve if filter is used in mills and automobiles.