Which substance is not regulated under NAAQS as a primary pollutant?

Which substance is not regulated under NAAQS as a primary pollutant?

• A. Carbon monoxide
• B. Lead
• C. Nitrogen dioxide
• D. Asbestos

Answer: (D)

The concept tested is how pollutants are categorized for ambient air quality standards. National Ambient Air Quality Standards (NAAQS) define primary pollutants as those for which the EPA sets ambient concentration limits to protect public health. The pollutants typically included are carbon monoxide, lead, nitrogen dioxide, sulfur dioxide, ozone, and particulate matter. Asbestos, while a serious health hazard when fibers become airborne, is not part of the NAAQS primary pollutant list. Instead, it is regulated as a Hazardous Air Pollutant under other provisions (NESHAP) and through specific construction, demolition, and workplace safety controls (OSHA). That distinction is why asbestos is the correct choice.

The concept tested is how pollutants are categorized for ambient air quality standards. National Ambient Air Quality Standards (NAAQS) define primary pollutants as those for which the EPA sets ambient concentration limits to protect public health. The pollutants typically included are carbon monoxide, lead, nitrogen dioxide, sulfur dioxide, ozone, and particulate matter. Asbestos, while a serious health hazard when fibers become airborne, is not part of the NAAQS primary pollutant list. Instead, it is regulated as a Hazardous Air Pollutant under other provisions (NESHAP) and through specific construction, demolition, and workplace safety controls (OSHA). That distinction is why asbestos is the correct choice.