Question

Increasing skin cancer and high mutation rate are the results of
a) Acid rain
b) Ozone depletion
c) CO pollution
d) (${ CO }_{ 2 }$) pollution

Answer 1

Hint: A protective layer is present in the stratosphere which absorbs harmful radiations of the sun. Alteration in this layer leads to an increased risk of diseases to all living organisms and even leads to global warming.

Complete answer:
Increasing skin cancer and a high mutation rate are the results of Ozone depletion. An increased amount of manufactured chemicals such as manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents are the major causes of ozone depletion in the stratosphere.
The need to maintain the ozone shield is obvious. However, certain anthropogenic pollutants are causing it to break down. Ozone in the stratosphere is a product of UV radiation acting on oxygen (${ O }_{ 2 }$) molecules. The high-energy UV radiation first causes some molecular oxygen (${ O }_{ 2 }$) to split apart into free oxygen (O) atoms and these atoms combine with the molecular oxygen to form ozone via the following reactions:
${ O }_{ 2 }+{ UVB }\xrightarrow [ \quad ]{ \quad } { O }+{ O}$ (1)
${ O }+{ O }_{ 2 }\xrightarrow [ \quad ]{ \quad } { O }_{ 3 }$ (2)
Not all the molecular oxygen is converted to ozone, however, because free oxygen, atoms may also combine with ozone molecules to form oxygen molecules, in the reaction.
${ O }+{ O }\xrightarrow [ \quad ]{ \quad } { O }_{ 2 }+{ O }_{ 2 }$ (3)
At last, when UVB is absorbed by ozone, it results in free oxygen and molecular oxygen.
${ O }_{ 3 }+{ UVB }\xrightarrow [ \quad ]{ \quad } { O }+{ O }_{ 2 }$ (4)
Thus, the amount of ozone in the stratosphere is dynamic; there is an equilibrium due to the continual cycle of reactions of formation and reactions of destruction.

So, the correct answer is ‘Ozone depletion’.

Note:
- The Northern Hemisphere has the highest ozone concentration in summer and lowest in winter because of seasonal changes in solar radiation.
- Ozone concentrations are highest at the equator and diminish as latitude increases as a function of higher overall amounts of solar radiation.