OZONE DEPLETION


WHAT I OZONE DEPLETION?

Ozone depletion is a phenomenon of depletion of ozone layer in the earth stratosphere to about 4 % observed since 1970. 

In this definition two words are on major focus. One is stratosphere and other is ozone layer.

Stratosphere:  Stratosphere is the second  atmosphere layer above the earth surface at the altitude of 10 km to 50 km from earth surface. 

OZONE LAYER

The ozone layer was discovered by French Physicsts Charles Fabry and Henry Buison in 1913.  Ozone layer is a layer of ozone in the stratosphere layer. It is deep layer containing ozone molecule. Ozone is a three oxygen atoms molecule.The region of stratosphere consisting of ozone layer is called ozonosphere. The ozonosphere lies in the altitude of 15-35 km from the earth surface. The thickness of ozone layer varies depending on geography and season. The maximum ozone concentration is found in tropics at the altitude of 26-28 km. At poles thickness of ozone is found between altitude of 12-20 km. 

ROLE OF OZONE LAYER

The sun emits very harmful radiation such as UV radiations. If these radiations reach on earth surface, they have devasting effects on humans, plants and animals. Ozone layer covers the earth. It protects us from these UV radiations by preventing them to reach on the earth surface. Ozone layer absorbs almost 97-99 % of UV radiations.

DEPLETION OF OZONE LAYER
CAUSES

The ozone depleting substatnces responsible for ozone depletion are as follows:

  • Chloroflorocarbons (CFCs)
  • Halogens
  • Methyl Chloroform
  • Carbon Tetrachloride
  • Hydrofluorocarbons
Chloroflorocarbons are the organic compounds consisting of chlorine, fluorine and carbon atoms. These are emitted from refrigerators, coolants, air conditioners, cleansing agents, cussions and mattress etc. They account for 80 % of ozone depletion. 

Halogens are more damaging than CFCs. They are Chlorine, Fluorine, Bromine, Iodine etc. They are found in fire extinguisher. 


OZONE HOLE

Ozone depletion in stratosphere layer during spring time at polar regions is refereed as ozone hole. Ozone has been depleted to such a extent that it created ozone hole. The consequences from ozone hole are reaching of UV radiation from sun to earth surface. Over Antarctica stratosphere region the ozone level has been decreased to as low as 33 % from 1975 values of ozone. Antarctic spring starts from September to December. In  this period ozone hole is caused. If the level of ozone depletion continues with same rate than one day there will be no layer to protect us from harmful sun UV radiations.

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