What is the primary role of ozone in the atmosphere?

What is the primary role of ozone in the atmosphere?

• A. To block UV radiation from reaching the earth's surface
• B. To heat the stratosphere
• C. To provide breathable oxygen
• D. To absorb infrared radiation from the sun

Answer: (A)

The key idea here is that atmospheric ozone acts as a UV shield, protecting living things from sun damage. In the stratosphere, ozone absorbs most of the Sun’s high-energy ultraviolet radiation, especially the dangerous UV-C and much of UV-B. This absorption prevents a large portion of harmful UV from reaching Earth’s surface, reducing risks like DNA damage, skin cancer, and ecological disruption. The heating of the stratosphere that accompanies this absorption is a consequence of the UV energy being deposited as heat, not the primary purpose of ozone. Ozone isn’t the source of breathable oxygen—ground-level ozone is actually a pollutant and harmful to inhale—so providing breathable oxygen isn’t its primary role. While ozone does absorb some infrared radiation, that’s a secondary effect and not its defining function.

The key idea here is that atmospheric ozone acts as a UV shield, protecting living things from sun damage. In the stratosphere, ozone absorbs most of the Sun’s high-energy ultraviolet radiation, especially the dangerous UV-C and much of UV-B. This absorption prevents a large portion of harmful UV from reaching Earth’s surface, reducing risks like DNA damage, skin cancer, and ecological disruption. The heating of the stratosphere that accompanies this absorption is a consequence of the UV energy being deposited as heat, not the primary purpose of ozone. Ozone isn’t the source of breathable oxygen—ground-level ozone is actually a pollutant and harmful to inhale—so providing breathable oxygen isn’t its primary role. While ozone does absorb some infrared radiation, that’s a secondary effect and not its defining function.