(a) Explain the role of UV radiation in producing ozone layer.
(b) Mention the reaction involved.
(c) Why is excessive use of CFCs a cause of concern?
Ozone is formed in the upper layers of the atmosphere where solar UV radiation dissociates oxygen molecules into oxygen atoms (O) and these atoms combine with another oxygen molecule (O 2 ) to form ozone (O 3 ).
The reaction involved is:
O 2 → O + O
O + O 2 → O 3
Excessive use of CFCs is a cause of concern because when it reaches the upper layers of the atmosphere, they cause depletion of ozone and this causes the harmful UV rays to reach the surface of the earth and create health hazards.