In the Clean Air Act permit program, how do PSD and NSR differ?

In the Clean Air Act permit program, how do PSD and NSR differ?

• A. NSR applies in nonattainment areas and uses LAER.
• B. PSD applies in attainment/unclassifiable areas for major new or modified sources and requires BACT; NSR applies in nonattainment areas and uses LAER.
• C. PSD handles minor sources only; NSR handles major sources only.
• D. PSD is for water permits; NSR is for air permits.

Answer: (B)

The key idea is that the permit program you use depends on the air quality status of the area and the level of control required for a major new or modified source. In areas that meet the air quality standards (attainment) or are unclassifiable, the Prevention of Significant Deterioration program applies to major new or modified sources, and the permit requires the best available control technology (BACT). In areas that do not meet the standards (nonattainment), New Source Review applies to major new or modified sources and requires LAER—the lowest achievable emission rate, which is more stringent to help bring the area into compliance. So, PSD = attainment/unclassifiable areas with BACT; NSR = nonattainment areas with LAER.

The key idea is that the permit program you use depends on the air quality status of the area and the level of control required for a major new or modified source. In areas that meet the air quality standards (attainment) or are unclassifiable, the Prevention of Significant Deterioration program applies to major new or modified sources, and the permit requires the best available control technology (BACT). In areas that do not meet the standards (nonattainment), New Source Review applies to major new or modified sources and requires LAER—the lowest achievable emission rate, which is more stringent to help bring the area into compliance. So, PSD = attainment/unclassifiable areas with BACT; NSR = nonattainment areas with LAER.