Question
- Why is the ozone layer required in the stratosphere? How does it get degraded? Explain.
- Why is the ozone depletion a threat to mankind?
✓
Answer
- Ozone layer in the stratosphere acts as a shield to absorb the ultraviolet radiation from the sun, which is highly injurious to living organisms.
- Chlorofluorocarbons (CFCs), from refrigerators and aerosol sprays, degrade the ozone layers.
- The UV rays act on the CFCs and release CI atoms, which degrade ozone to molecular oxygen.
- In the absence of ozone, which absorbs the ultraviolet radiation, the UV rays reach the earth and cause the following ill-effects.
- (i) UV-B damages DNA and causes mutation in living organisms.
- (ii) It causes ageing of skin, damage to skin cells and various types of skin cancers.
- (iii) A high dose of UV-B causes inflammation of cornea, called snow blindness, cataract and even permanent damage to cornea.
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