According to research, it is estimated that an average adult male breathes in 15 kg of air a day, in comparison to about 1.5 kg of the food consumed and 2.5 kg of water intake. Hence it is obvious that the quantum of pollutants that enter our body through respiration would be manifold in comparison to those taken in through polluted water or contaminated food.
Air is a mixture of gases comprising 78% nitrogen, 21 % oxygen and a little less than 1% argon, together with 0.03% carbon dioxide. These elements make up to 99.9% of dry air. As long as this composition is maintained, the air is pure. If this composition is altered, i.e. the oxygen level gets reduces or other harmful gases enter the atmosphere, then the air is said to be polluted and inhalation of this polluted air can lead to respiratory disorders.
Effects of Air Pollution-
It affects human health, animals, and plants causing global effects.
Lung cancer is a disease caused by polluted air which leads to death. It is mostly associated with respiratory diseases ranging from common cold to lung cancer.
Gaseous and particulate pollutants cause emphysema, bronchitis and asthma. Polluted air irritates the eyes and pollutants like lead accumulates in the body.
The prominent gaseous pollutants are carbon monoxide, sulphur dioxide, oxides of nitrogen, hydrogen sulphide, cetain acid, aldehydes and hydrocarbons.
The particulate pollutants include dust, silicious matter and asbestos. Carbon monoxide reacts with the haemoglobin reducing the oxygen- carrying capacity of blood. Persons suffering from anaemia are more prone to get affected as carbon monoxide leads to serious injuries.
Sulphur dioxide is the most serious and widespread air pollutant as lower levels of sulphur dioxide cause temporary spasm of the smooth muscles of the bronchia.
Higher concentration of sulphur dioxide induces increased mucus production. The cilia protecting respiratory system is affected by it causing cough, shortness of breath, spasm of larynx, acute irritation of the eye membranes resulting in tears and redness.
Oxides of nitrogen are pulmonary irritants and excess concentration lead to pulmonary haemorrhage.
Hydrogen sulphide is well known for its characteristic rotten-egg odour. Hydrocarbons emitted from automobile exhaust cause lung cancer.
Controlling Air Pollution
Much of the pollution can be averted through careful planning and setting up of industries, better designed equipments and proper operation of the equipments.
Complete combustion-i.e. ensuring there complete burning so that poisonous carbon monoxide gets converted to harmless carbon dioxide. The combustion can be increased by reducing the size of the fuel and adjusting the ration of air to fuel.
Tree Plantation- more and more trees need to be planted in and around an industry and also along the roadside and in the houses located in the vicinity of the industry. Trees are capable of absorbing more of carbon dioxide and help reduce the atmospheric carbon dioxide levels, thus maintaining equilibrium in the air composition.
Preventing vehicle pollution- many techniques for this purpose have been developed. These include tune-ups, catalytic reactors and engine modification. A tune up has a significant effect on emission compounds. The catalytic reactor oxidizes toxic carbon monoxide to the innocuous carbon dioxide, thereby reducing the nitrogen oxides to nitrogen.
Be ozone friendly- there is no easy solution to the depleting ozone layer. Even if a ban on the production of CFC is imposed with immediate effect, the effects of the CFC produced till date will continue to harm the atmosphere for coming years. However if all the nations work together, this can be prevented.