Epidemiological studies have shown that a sudden increase in air pollution has often been associated with immediate increase in the mortality and morbidity. The symptoms are usually referable to the respiratory system. Even a small increase in air pollution has been shown to be accompanied by a small but definite increase in mortality and morbidity.

Headache, faintness, sickness, vomiting and diarrhea are often caused by the foul air of rooms, public halls, theatres and other overcrowded and badly ventilated buildings People who constantly live under such conditions suffer from loss of appetite, sleeplessness, low spirits and general bad health.

The disease of the lungs such as bronchitis and pneumonia, smallpox, measles, diphtheria, dysentery, cholera, plague, diseases of the skin and eyes and numerous other diseases are often caused due to the bad and impure air. It is a well known fact that far more sickness prevails in dirty cities, towns, villages and houses than in places which are kept clean a-d where the air is fresh and pure.

Bisiufection of Air:


In recent years disinfection of air has received much attention. Every attention should be paid to the following factors are keeping the air pure:

(i) Careful construction and cleanliness of houses, streets, roads, drains, latrines etc.

(ii) Immediate removal and careful disposal of the refuses of all kinds.

(iii) Liberal supply of water for cleansing purposes


(iv) Careful cleaning of houses, bodies and clothes;

(v) Provision for out let of the smoke in kitchen houses;

(vi) Prohibition of cooking in bed rooms.



The most important means of purifying the impure air is ventilation. Ventilation means the removal of the impurities of the air of inhabited rooms and buildings with fresh air from the outside, admitted through the win­dows doors or other openings. Ventilation reduces vitiated air and bacterial density. The following are some of the ways in which ventilation is affected.

(i) Diffusion:

The mixing of the impure air of rooms with the fresh outside air is known as the ‘diffusion of gases’. Fire-places in cold countries help diffusion considerably. The hot impure air being lighter than cold air, rushes up through the chimney, and its place is taken by the cold pure air from the outside.

Generally the electric fans are used during the hot weather for the purpose of keeping the air in motion, and thereby cause an in draught of air from the outside. The impurities of the air are also thus got rid of to some extent. Fans driven by steam are often used for ventilating the engine rooms, large public schools, mills and other similar buildings. Central air shafts in which fires are kept burning to create an upward draught are also sometimes used for ventilating purposes in coal mines


(ii) Wind:

Wind helps considerably in the ventila­tion of building by forcibly removing the impurities of the air.

(iii) Rain:

After a heavy and continuous shower of rain the air becomes pure and fresh, due to the fact that the dust and other impurities are washed out from the air.


(iv) Green Plants:

Green plants use the carbon-dioxide for their nutrition and growth, and set the oxygen free, which is useful for the purification of air.

The best test of the impurity of air is smell. For emitting the fresh air in to the rooms and to prevent the smallest trace of smell, the doors, windows add other openings should be kept open as far as possible during day and night.

Especially during sickness the fresh air is needed. But it is a common practice in Indian families to shut up doors and windows during sickness, which is exceedingly dangerous. So rooms and building should be well venti­lated and there should be provision for cross-ventilation.