Which pollutants are designated as criteria pollutants under the NAAQS?

Which pollutants are designated as criteria pollutants under the NAAQS?

• A. Mercury, Lead, Cadmium
• B. Radon, Ozone, Particulate matter
• C. CO2, CH4, N2O, CFCs
• D. PM2.5, PM10, SO2, NO2, CO, O3, and Pb

Answer: (D)

Criteria pollutants are the pollutants for which the EPA establishes the National Ambient Air Quality Standards to protect public health from typical outdoor exposures. The designated list includes ozone, particulate matter in two size categories (PM2.5 and PM10), carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead (Pb). Particulate matter is tracked in two sizes because health effects differ by particle size, with PM2.5 representing fine particles that can reach deep into the lungs. Ozone is a secondary pollutant formed in the atmosphere by sunlight-driven reactions of NOx and VOCs. The other options mix in pollutants that are not part of the NAAQS criteria pollutant list, such as radon or greenhouse gases like CO2, CH4, N2O, and CFCs, which are regulated under different programs or contexts. Lead is included among the criteria pollutants. Therefore, the set that matches the NAAQS criteria pollutants is PM2.5, PM10, SO2, NO2, CO, O3, and Pb.

Criteria pollutants are the pollutants for which the EPA establishes the National Ambient Air Quality Standards to protect public health from typical outdoor exposures. The designated list includes ozone, particulate matter in two size categories (PM2.5 and PM10), carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead (Pb).

Particulate matter is tracked in two sizes because health effects differ by particle size, with PM2.5 representing fine particles that can reach deep into the lungs. Ozone is a secondary pollutant formed in the atmosphere by sunlight-driven reactions of NOx and VOCs. The other options mix in pollutants that are not part of the NAAQS criteria pollutant list, such as radon or greenhouse gases like CO2, CH4, N2O, and CFCs, which are regulated under different programs or contexts. Lead is included among the criteria pollutants. Therefore, the set that matches the NAAQS criteria pollutants is PM2.5, PM10, SO2, NO2, CO, O3, and Pb.