Pollution
Pollution is the introduction into the environment of substance that harms the health and affects the survival or activity of living organisms. Pollution can also be defined as any modification of the environment- physical, chemical or biological –which threatens the life, activities or health of human beings or other living organisms. Substances which cause pollution are called pollutions.
Pollutants are of two types- biodegradable and nonbiodegradble. Pollutants which can be broken down by biological agents, like microorganisms and soil animals, are said to be biodegradable. These comprise organic waste, or substances of plant or animal origin. A few examples are animal excreta, leaf litter, kitchen waste, waste paper and crop residue. If managed properly, this class of pollutants can be turned into useful resources.
Substances which cannot be broken down by biological agents are called nonbiodegradble pollution. Metals, plastic, glass pesticides and detergents are some nonbiodegradble pollutants.
Air pollution
The main causes of air pollution are the burning of wood. Air pollutants can be smoke and gases.
The burning of fossil fuels produces carbon dioxide, carbon monoxide, sulphur, dioxide, oxides of nitrogen and hydrocarbons. Of these, carbon dioxide is not really harmful for health, but it has an impact on the environment.
Among The harmful solid particles emitted by the burning of fossil fuel are lead particles from automobile exhaust and fly ash from thermal power stations. Some of the most polluting industries, in terms of the release of harmful particles into air, are the iron and steel and mining industries. Oil refiners and industries manufacturing chemicals, cement and asbestos are some others. Lead, added to the petrol used in vehicles, can damage the respiratory system and affect the liver and kidneys.
Controlling air pollution
Though we cannot close down industries or stop using automobiles, we can control the pollution caused by them. Many countries, including India, have enacted laws for the control of pollution. Let us discuss the lows related to air pollution and the steps that can be taken to control it.
a) The central pollution control board enforces the law related to pollution, including the air (prevention and control of pollution) act. This act sets out penalties for industries and organizations found guilty of causing pollution beyond certain specified limits. It also lays down standards for vehicular emissions. Anyone who owns a vehicle that violates these standards can be fined.
b) Industries are supposed to filter harmful substance from the emissions coming out of heir chimneys. Solid particles are separated from the gaseous. Waste by using gravity-settling chambers. As the gases pass through these chambers, the particles settling under the action of gravity. Harmful gases can be removed from industrial emissions with the help of scrubbers. These screens containing solvents or absorbers that dissolves or absorb the harmful gases.
c) Polluting industries should be located away from inhabited areas and ecologically sensitive areas, such as sanctuaries and parks. Besides, the chimneys should be tall facilities the dispersal of the emissions by the wind.
d) Any large industry which may have an impact on human health and the environment is supposed to make an impact assessment and draw up a plan on how it will reduce it. It can start functioning only after it gets approval from the government on the basis of this assessment.
e) Industries can adopt fuel-efficient technologies to reduce pollution and save fuel.
f) As for vehicles, many technologies are being developed to reduce the consumption of fuel and the emission of pollutants. Switching to unleaded petrol or compressed natural gas (CNG) helps reduce pollution. CNG is considered to be the cleanest fossil fuel. Other ways of reducing consumption and pollution are to use public transport, from car pools and walk whenever possible.