Which class of pollutants acts as a precursor to ground-level ozone formation?

Which class of pollutants acts as a precursor to ground-level ozone formation?

• A. Particulate Matter
• B. Lead
• C. Volatile Organic Compounds
• D. Ozone

Answer: (C)

Ground-level ozone is a secondary pollutant formed when sunlight drives reactions between nitrogen oxides and reactive organic compounds. The substances that start this process are the volatile organic compounds, which release reactive organic radicals that help oxidize NO to NO2 and sustain ozone formation in the daytime. VOCs come from solvents, fuels, and many industrial processes, as well as some natural sources. The other options are not precursors to ozone formation: particulate matter and lead are emitted directly as pollutants, and ozone itself is the product of the reactions, not a starter.

Ground-level ozone is a secondary pollutant formed when sunlight drives reactions between nitrogen oxides and reactive organic compounds. The substances that start this process are the volatile organic compounds, which release reactive organic radicals that help oxidize NO to NO2 and sustain ozone formation in the daytime. VOCs come from solvents, fuels, and many industrial processes, as well as some natural sources. The other options are not precursors to ozone formation: particulate matter and lead are emitted directly as pollutants, and ozone itself is the product of the reactions, not a starter.