Mar 26, 2021 · Lower thresholds apply in non-attainment areas (but only for the pollutant that are in non-attainment). (See Table below). Major source thresholds for “hazardous air pollutants” (HAP) are 10 tons/year for a single HAP or 25 tons/year for any combination of HAP. The EPA generally has not required non-major sources to get permits (except as