Ozone Depletion — Prelims Strategy

Prelims Strategy

To effectively tackle NEET questions on ozone depletion, a multi-pronged strategy is recommended. Firstly, focus on memorizing the key Ozone Depleting Substances (ODS) such as Chlorofluorocarbons (CFCs), Halons, Carbon tetrachloride, and Methyl bromide.

Understand that these substances release highly reactive chlorine and bromine atoms in the stratosphere. Secondly, clearly distinguish between the effects of ozone depletion and global warming; this is a frequent trap.

Ozone depletion leads to increased UV-B radiation, causing skin cancer, cataracts, and immune suppression, and harming phytoplankton. Global warming is about increased temperature due to greenhouse gases.

Thirdly, commit the Montreal Protocol (1987) to memory as the primary international agreement addressing ozone depletion, recognizing its success. For conceptual questions, visualize the process: ODS released $\rightarrow$ drift to stratosphere $\rightarrow$ UV breaks them down $\rightarrow$ Cl/Br atoms destroy ozone $\rightarrow$ more UV reaches Earth $\rightarrow$ biological damage.

Pay attention to keywords like 'stratosphere' for good ozone and 'troposphere' for bad ozone. When faced with options, eliminate distractors that relate to other environmental issues. For example, if a question asks about the effects of ozone depletion, options related to acid rain or smog are likely incorrect.

Practice identifying the correct chemical formulas for ODS. Finally, be aware of the 'ozone hole' phenomenon, specifically its occurrence over Antarctica and the role of polar stratospheric clouds.