Which of the following would be a consequence of extensive exposure to ozone-depleting substances?

• A. Increased ozone concentration
• B. Decreased UV radiation
• C. Increased UV radiation reaching Earth
• D. No change in UV exposure

Answer: (C)

Ozone in the stratosphere acts as a shield, absorbing most of the sun’s ultraviolet radiation. When ozone-depleting substances release chlorine and bromine radicals, they drive catalytic cycles that destroy ozone molecules. As the ozone layer becomes thinner, its capacity to absorb UV decreases. With less ozone to absorb it, more UV radiation—especially UV-B—reaches Earth's surface. That is exactly the consequence of extensive exposure to these substances. The other possibilities would require the ozone layer to become thicker or UV to be absorbed more, which isn’t what happens with ozone-depleting substances.