EPA has two distinct air permitting programs for sources with the potential to emit (PTE) air pollutants above major source thresholds. The construction permit program, referred to as New Source Review (NSR) is divided into nonattainment NSR for major sources in nonattainment areas, and prevention of significant deterioration (PSD) for major sources in attainment areas. The requirements of an NSR permit are designed to ensure that emissions from the construction or modification of source do not have an adverse impact on ambient air quality in the area. The operating permit program, often referred to as Title V, consolidates all of the applicable requirements, including cap and trade program requirements, into a single document, thus simplifying compliance.

Sources with a PTE below major source thresholds are not required to comply with nonattainment NSR, PSD, or Title V. These sources are typically subject to state air permitting requirements for minor sources.