Life cannot exist without air. Pure air is essential for healthy life and the purity of the atmosphere has direct impact on the relation between health and diseases. The uncomfortable feeling in a place is mainly due to the high temperature, excess of water-vapor and lack of air, movement which cause beat stagnation.
Of the two most essential elements that sustain life, air is of greater importance than water, as life cannot be sustain without air (oxygen) for more than 3 minutes, but one can survive for a few days without water. For maintenance of healthy life pure air is necessary, because it purifies the blood by interchange of O2 with CO2 in the lungs. It also regulates the body temperature and promotes digestion and assimilation. Air strengthens the body and nerves, improves metabolism, increases resistance against disease, etc.
Air is a mechanical mixture and not a chemical compound and the composition of air is more or less constant. Water vapor varies with temperature. Traces of ammonia, organic matter, salts of sodium, ozone, dust and other mineral substances are also present in a variable quantity. Nitrogen acts as diluents of oxygen. The uniformity of the composition of air is maintained by means of diffusion, constant movement due to air current and reciprocal actions of animals and the plants in air.
Truly speaking, there has never been pure air. Foreign substances have been present in the air at all times and at all places. Air may be polluted from the different sources but there is constant natural purification of air which is being done by
1.Rain. -Rain washes the air by removing the suspended impurities in the atmosphere.
2.Wind.- Wind helps in dilution sweeping away the impure air that will be replaced by pure air
3.Chlorophyll. -Chlorophyll is present within the green leaves of the plants.
4. Oxygen and ozone. They help to oxidize the present organic matter.