OZONE LAYER DEPLETION

OZONE LAYER DEPLETION AND ITS EFFECT

Ozone is present in all atmospheric regions. But the formation and transformation of ozone takes place in stratosphere. This layer of the atmosphere plays a vital role on life on the earth. Ozone absorbs the UV radiation from the sun, thereby protecting life on our planet. Ozone formation occurs rapidly in the atmosphere above the equatorial regions, where solar radiations is more intense. Much of this ozone is transferred to the poles by the air masses, which moves in horizontal direction.

In stratosphere the air masses only move in a horizontal direction. Due to this condition, pollutants can remain in stratosphere for hundreds of years. A prime destroyer of ozone is Chloroflurocarbons

The pollutants especially that of aerosol(from the rockets and aircrafts) CFCs, HFC’s (fossil burning) etc gets dispersed in the air and can reach high region of the stratosphere(upto 60 miles above the earth ). These pollutants in stratosphere destroy the ozone layers. The continous attack by the pollutants leads to the thinning of ozone layer. Thinning of ozone layer was termed as ozone hole. The depletion of ozone layer leads to penetration of more ultra violet radiation on biosphere. Increased UV radiation elevates the incidence of cataract, skin diseases (skin cancer) and affects the functioning of the immune system.

Damages nucleic acids in the living organisms. UV radiation inhibit photosynthesis in plants and phytoplankton, which in turn affect the whole food chain.

What are CFC’s?

Chloroflurocarbons constitute a family of man made chemical compound. It was invented in the 1930’s. they are non-toxic and harmless to handl. CFC’s are extremely stable and non-flammable. This stability gives them a long life span in the atmosphere allowing its transport to the stratosphere. In stratosphere UV radiation releases chlorine from the rest of the molecule. A single chlorine atom can destroy thousands of molecules of ozone. CFC is used in refrigerators.

GREEN HOUSE EFFECT

The green house effect is a warming that helps to maintain an average global temperature of approximately 60’ farhenheit. During this process sunlight enters earths atmosphere as a short wave radiation which is absorbed by earth’s surface. The planet becomes heated and emits lomg wave radiation towards the atmosphere in which the green house gases absorb them, and in the process gets energitized and emits energy in all directions. Due to this process the temperature of the earth is increasing.

According to the National Academy of sciences the earths surface temperature has risen by about 1’F in the past century.

Problem arises even due to the increase in the concentration of these green house gases. The 20^th century warmest year occurred in the 1998. the snow cover in the northern hemisphere and the ice of the Artic shelf has decreased globally. The sea level has risen by 418 inches over the past century.

Man made green house gases which are found to be the most heat absorbant are hydroflurocarbons(HFC’s), perfluorocarbons (PFC) and sulphur hexafluoride(SF6).

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