What is the beneficial function of ozone located in the stratosphere?

• A. It blocks most ultraviolet radiation from entering the troposphere
• B. It traps heat in the lower atmosphere
• C. It dissolves pollutants in rain
• D. It provides oxygen for breathing in the troposphere

Answer: (A)

Stratospheric ozone acts as a natural sunscreen for the planet. Its main beneficial function is to absorb most of the Sun’s ultraviolet radiation, especially UV-B and UV-C, before it can reach the troposphere. By filtering this harmful radiation, it helps protect living organisms from DNA damage, skin cancer, cataracts, and other ecological and health impacts. Some UV-A still gets through, but the overall reduction is substantial.

Other statements mix up different processes. Ozone in the stratosphere isn’t about dissolving pollutants in rain, and it doesn’t provide breathable oxygen to the air we breathe in the troposphere—ground-level ozone is actually a harmful pollutant. While ozone interacts with radiation, the key beneficial role here is shielding against ultraviolet radiation rather than trapping heat beneath.