In the stratosphere, ozone is actually formed by the action of UV rays on Dioxygen molecules(O2).
(i) O2(g) O(g) +O(g)
(ii) O2(g) + O(g) O3(g)
The second reaction demonstrates that the breakdown and synthesis of ozone molecules are in a dynamic equilibrium. Any factor that disrupts this balance might cause the ozone layer to decrease due to breakdown. Chlorofluorocarbon molecules are one example of these variables (CFCs). These molecules are non-flammable and non-reactive and are used in air conditioners, refrigerators, polymers, and electronics.
When CFCs are released into the atmosphere, they mix with atmospheric gases before reaching the stratosphere, where UV light causes them to disintegrate.
(iii) CF2Cl2(g) l(g) +F2Cl(g)
The chlorine free radical which is produced in the third reaction reacts with ozone as shown below:
(iv) l(g) + O3(g) Cl\dot{O} (g) + O2(g)
And, Cl{O} (g) + O(g) \ {C}l(g) + O2(g)
The radicals, on further reaction with atomic oxygen, resulting in the production of more chlorine radicals.
This regeneration of chlorine-free radicals results in a continuous breakdown of ozone in the stratosphere, thus almost permanently damaging the ozone layer.
