Attainment Status and De Minimis Thresholds 40 CFR §93.153 (7-1-11)
Abstract
Conformity determinations for Federal actions related to transportation plans, programs, and projects developed, funded, or approved under title 23 U.S.C. or the Federal Transit Act (49 U.S.C. 1601 et seq.) must meet the procedures and criteria of 40 CFR part 51, subpart T. For Federal actions not covered by paragraph (a) of this section, a conformity determination is required for each criteria pollutant or precursor where the total of direct and indirect emissions of the criteria pollutant or precursor in a non-attainment or maintenance area caused by a Federal action would equal or exceed any of the rates shown in the tables of this document. They include de minimis rates for non-attainment areas (NAAs) and maintenance areas for criteria pollutants.