Which pollutants are typically tracked for NAAQS in Colorado ambient monitoring?

• A. Ozone (O3), fine particulate matter (PM2.5), coarse particulate matter (PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and lead (Pb).
• B. Arsenic, Mercury, Cadmium, Chromium
• C. Methane, Ethane, Propane
• D. Only PM2.5 and O3.

Answer: (A)

National Ambient Air Quality Standards target seven primary pollutants, and Colorado’s ambient monitoring focuses on these so that air quality can be assessed against health-based standards. The pollutants tracked are ozone, PM2.5 (fine particulate matter), PM10 (coarse particulate matter), carbon monoxide, nitrogen dioxide, sulfur dioxide, and lead. This full set matches the standard list used nationwide, making it the best choice.

Other options mix in substances not part of the NAAQS set, such as certain hazardous air pollutants (heavy metals) or general hydrocarbons, or they omit several of the seven criteria pollutants.