It is the burning of fossil fuels that release pollution into the air. Even burning biomass- based fuel, or bio fuels, causes’ pollution. The biomass of an organism is its total dry mass or weight. When we speak of biomass –based fuels, we mean fuels like wood, crop residue and dung cakes. The burning of such fuels produces carbon dioxide, carbon monoxide, methane and other hydrocarbons, besides sot and ash.
The decomposition of organic matter, including agricultural waste, also produces methane and other pollutants. Agricultural processes like threshing and winnowing release solid particulates into the air, pollen grains, spores and emissions from forest fires are some natural sources of air pollution.
Acid rain
The oxides of sulphur and nitrogen released into the air damage the environment in yet another way. They combine with rain water to forms sulphuric and nitric acids and come own as acid rain. Acid rain herm plants, affects soil fertility, and even corrodes buildings, bridges and monuments. It is said that the marble of the Tajmahal is getting corroded by acid rain caused by realize of sulphur dioxide from the oil refinery.
Green house
The earth gets heat from the sun. When the surface of the earth becomes warm, it radiates heat towards space. Carbon dioxide in the air traps some of this heat by sending a part of it back towards the earth. The trapped heat keeps the earth comfortably warm. This is similar to the way the glass walls of a greenhouse trap heat inside it. That is why trapping of heat by carbon dioxide and some other gases in the air is called the greenhouse effect. The gasses which cause this effect are called greenhouse gases. Methane too acts as a greenhouse gas.
When the air contain more than the normal proportion of greenhouse gases, more than the normal amount of radiation (heat) is trapped. This mistakes the atmosphere more than normally warm. This phenomenon, called global warming, is said to be caused by the increasing consumption of fossil fuel. Many scientists believe that the impact o global warming has already started, as is evident from the frequent disturbances in global weather patterns. They hold it responsible for the increase in the number of cyclones the world over, unprecedented floods and melting of the ice cover in the Arctic region, for example.
*Dig a small pit in your garden or in one corner of the office grounds. Fill it up with layers of shredded vegetable waste, green leaves, and paper, and cloth, plastic and wood shavings, interspersed with layers of soil. Cover it up with a final layer of soil and sprinkle water over it. Keep moistening the soil from time to time. Dig out the pit after 2-3 weeks. Which of the wastes buried in the pit does not undergo any decomposition at all?
Some nonbiodegradble pollutants, for example, glass, plastic and metals like iron and copper, can be recycled. That means they can be melted down and made into new things. Other like compounds o lead, mercury and arsenic, are toxic, or poisonous, to living beings.
