Ozone depletion is mainly caused by which chemicals?

Ozone depletion is primarily caused by Chlorofluorocarbons (CFCs). These synthetic organic compounds were widely used as refrigerants, aerosol propellants, and in fire extinguishers due to their stability. However, their stability allowed them to reach the stratosphere without breaking down. Once in the stratosphere, intense ultraviolet (UV) radiation breaks down CFCs, releasing chlorine atoms. These chlorine atoms then act as catalysts, reacting with and destroying thousands of ozone (O3) molecules through a chain reaction, thereby thinning the protective ozone layer that shields Earth from harmful UV radiation. The Montreal Protocol was established to phase out the production of CFCs and other ozone-depleting substances.

• Option A, Carbon dioxide, is a major greenhouse gas contributing to global warming, but it does not directly cause ozone depletion.
• Option C, Nitrogen gas, is the most abundant gas in the atmosphere and is largely inert in terms of ozone depletion, though certain nitrogen oxides can play a role, they are not the primary cause.
• Option D, Methane, is also a potent greenhouse gas that contributes to climate change, but it is not the main chemical responsible for direct ozone depletion.