What condition defines a non-attainment area?

• A. inability of a region to meet the National Ambient Air Quality Standards (NAAQS)
• B. inability of a region to meet the National Emission Standards for Hazardous Air Pollutants (NESHAP)
• C. inability of a region to meet New Source Performance Standards (NSPS)
• D. None of the above

Answer: (A)

Non-attainment means the outdoor air in a region does not meet the set National Ambient Air Quality Standards for one or more pollutants, based on monitoring data. This designation focuses on ambient air quality in the environment, not on how much a single source is emitting. Emission-based standards like NESHAP and NSPS regulate what sources can emit, while non-attainment is about actual air quality levels measured in the area. If monitoring shows exceedances, the area is designated non-attainment for that pollutant and must implement stricter state plans to reduce pollution and achieve attainment.