Which statement best describes ground-level ozone in relation to smog?

Which statement best describes ground-level ozone in relation to smog?

• A. It is the good ozone found in the upper atmosphere.
• B. Ground-level ozone is the main ingredient of smog.
• C. It is unrelated to air quality.
• D. It only affects water quality.

Answer: (B)

Ground-level ozone is the pollutant formed in the lower atmosphere when sunlight drives chemical reactions between precursors like nitrogen oxides and volatile organic compounds from vehicles and industry. This ozone is a major part of photochemical smog, giving that characteristic hazy, polluted air and contributing to respiratory and heart problems. It’s important to contrast this with the “good ozone” up in the stratosphere, which protects us from UV radiation; the ozone that drives smog is the harmful, ground-level variety. Ground-level ozone is not unrelated to air quality, and it does not relate to water quality, so describing it as the main ingredient of smog best captures its role.

Ground-level ozone is the pollutant formed in the lower atmosphere when sunlight drives chemical reactions between precursors like nitrogen oxides and volatile organic compounds from vehicles and industry. This ozone is a major part of photochemical smog, giving that characteristic hazy, polluted air and contributing to respiratory and heart problems. It’s important to contrast this with the “good ozone” up in the stratosphere, which protects us from UV radiation; the ozone that drives smog is the harmful, ground-level variety. Ground-level ozone is not unrelated to air quality, and it does not relate to water quality, so describing it as the main ingredient of smog best captures its role.