Which statement about ozone is true?

Which statement about ozone is true?

• A. Ozone in the stratosphere protects life by absorbing UV radiation
• B. Ozone in the troposphere is always beneficial
• C. Ozone has no effect on climate
• D. Ozone is only a greenhouse gas in the stratosphere

Answer: (A)

Ozone has very different roles depending on where it sits in the atmosphere. In the stratosphere, a layer of ozone absorbs most of the sun’s harmful UV-B and UV-C radiation, which protects living things from skin cancer, cataracts, and ecosystem damage. Ground-level, or tropospheric, ozone forms from reactions of pollutants in sunlight and is a respiratory irritant that harms people and crops; it also acts as a greenhouse gas and influences climate. Because ozone affects climate and health in both layers, the idea that it has no climate effect is false, and the notion that it’s only a greenhouse gas in the stratosphere is incorrect. The statement that best reflects reality is that stratospheric ozone protects life by absorbing UV radiation.

Ozone has very different roles depending on where it sits in the atmosphere. In the stratosphere, a layer of ozone absorbs most of the sun’s harmful UV-B and UV-C radiation, which protects living things from skin cancer, cataracts, and ecosystem damage. Ground-level, or tropospheric, ozone forms from reactions of pollutants in sunlight and is a respiratory irritant that harms people and crops; it also acts as a greenhouse gas and influences climate. Because ozone affects climate and health in both layers, the idea that it has no climate effect is false, and the notion that it’s only a greenhouse gas in the stratosphere is incorrect. The statement that best reflects reality is that stratospheric ozone protects life by absorbing UV radiation.