Proposed Changes to Transportation Conformity Rules Address New Ozone and PM-2.5 NAAQS

摘要

On November 5, 2003 (68 FR 62690-62729), EPA proposed changes to the agency's transportation conformity regulations in 40 CFR Part 93 to include criteria and procedures for the new ozone and particulate matter NAAQS (national ambient air quality standatds). Transportation conformity is required under CAA Section 176(c) to ensure that federally supported highway and transit activities are consistent with (i.e., "conform to") the purpose of a state implementation plan (SIP). The proposed rule provides guidance on when conformity will first apply in areas that are designated non-attainment for the eight-hour ozone NAAQS and the NAAQS for PM-2.5 (particulate matter with an aerodynamic diameter ≤2.5 microns). In addition, the proposed rule describes the general requirements for conducting conformity determinations for the new NAAQS.