Some of the steps we can take to prevent air pollution are as follows:
1. Control of Gaseous Pollutions:
The equipment’s which can be used to control gaseous pollutants are classified as combustion, absorption and adsorption equipment’s. Combustion is applicable to pollutant gases which are oxidizable. In petrochemical, fertiliser, paint and varnish industries combustion control equipment’s are useful.
Absorption is a diffusional process in which the transfer of gas molecules into a liquid phase takes place. Such equipment’s include spray chambers, packed towers and sieve plate contractors.
Absorption is the means of controlling air pollution which occurs due to some gases and vapours and inflammable compounds which cannot be treated by other means.
2. Control of Emission from Motor Vehicles:
The emission control techniques include tune-ups, catalytic reactors and engine modifications. A high air-fuel ratio will reduce the concentrations of both carbon monoxide and hydrocarbons.
The modified engines have an efficient system of burning of the fuel. At present, there is no system of reduction of sulphur dioxide, although researches in this direction are in progress throughout the world.
3. Control of Aerosol Emissions:
This can be controlled by arresters and scrubbers. Arresters include inertial separators, filters and precipitators. The electrostatic precipitator is considered to be the most effective device for preventing the emission of dust from fuel gases and is the standard equipment for large power stations.
4. Control by Fuel Selection and Utilisation:
Coal and oil are the primary fuels in which smoke, grit and sulfur dioxide are the major pollutants. Coal pollutes more because it releases more smoke and carbon in the air. Instead of coal, oil can be used. But, in oil, the amount of sulphur dioxide emission is higher.
Therefore, fuel selection should be done properly and the harmful impact be restricted by inducing other chemicals. In order to control smoke, the coal is pulverised before being used. When oil is used for fuel, it is essential that the ratio of air should be maintained constant in order to prevent smoke emissions.
5. Control of Air Pollution by Site Selection and Zoning:
Selection of an industrial site is the most important factor through which impact of air pollution can be minimised.
The industrial site should be selected considering:
(i) Residential areas,
(ii) Nature of industries, and
(iii) Climatic conditions, specially the direction of winds. The site of each and every industry should have an approval from the department of environment.
It should be approved in taking into consideration the long term perspective rather than immediate effects. Within the city the location of industrial zone is a critical aspect and town planners should have a check over its location as well as unorganized growth. Apart from the above, legal controls are also there.
The UNO and WHO have issued guidelines to its member-nations for the formulation of laws regarding prevention of air pollution and accordingly all the countries of the world have enacted certain laws. In India, the Prevention of Air and Water Pollution Act, 1974, 1981, the Air Prevention and Control of Pollution Act, 1981, and the Environmental Protection Act, 1986 have been enacted, but they are not followed in a strict manner.
Actually, the most important aspect is public awareness about air pollution because the government alone cannot prevent it. It can be checked only through the combined efforts of the government, NGOs and the public.