(a) Action applicability.

(1) Except as provided for in paragraph (c) of this section or §93.126, conformity determinations are required for:

(i) The adoption, acceptance, approval or support of transportation plans and transportation plan amendments developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT;

(ii) The adoption, acceptance, approval or support of TIPs and TIP amendments developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT; and

(iii) The approval, funding, or implementation of FHWA/FTA projects.

(2) Conformity determinations are not required under this subpart for individual projects which are not FHWA/FTA projects. However, §93.121 applies to such projects if they are regionally significant.

(b) Geographic applicability. The provisions of this subpart shall apply in all nonattainment and maintenance areas for transportation-related criteria pollutants for which the area is designated nonattainment or has a maintenance plan.

(1) The provisions of this subpart apply with respect to emissions of the following criteria pollutants: ozone, carbon monoxide (CO), nitrogen dioxide (NO2), particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM10); and particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers (PM2.5).

(2) The provisions of this subpart also apply with respect to emissions of the following precursor pollutants:

(i) Volatile organic compounds (VOC) and nitrogen oxides (NOX) in ozone areas;

(ii) NOX in NO2 areas;

(iii) VOC and/or NOX in PM10 areas if the EPA Regional Administrator or the director of the State air agency has made a finding that transportation-related emissions of one or both of these precursors within the nonattainment area are a significant contributor to the PM10 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy;

(iv) NOX in PM2.5 areas, unless both the EPA Regional Administrator and the director of the state air agency have made a finding that transportation-related emissions of NOX within the nonattainment area are not a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or the applicable implementation plan (or implementation plan submission) does not establish an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy; and

(v) VOC, sulfur dioxide (SO2) and/or ammonia (NH3) in PM2.5 areas either if the EPA Regional Administrator or the director of the state air agency has made a finding that transportation-related emissions of any of these precursors within the nonattainment area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.

(3) The provisions of this subpart apply to PM2.5 nonattainment and maintenance areas with respect to PM2.5 from re-entrained road dust if the EPA Regional Administrator or the director of the State air agency has made a finding that re-entrained road dust emissions within the area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) includes re-entrained road dust in the approved (or adequate) budget as part of the reasonable further progress, attainment or maintenance strategy. Re-entrained road dust emissions are produced by travel on paved and unpaved roads (including emissions from anti-skid and deicing materials).

(4) The provisions of this subpart apply to maintenance areas through the last year of a maintenance area's approved CAA section 175A(b) maintenance plan, unless the applicable implementation plan specifies that the provisions of this subpart shall apply for more than 20 years.

(c) Limitations. In order to receive any FHWA/FTA approval or funding actions, including NEPA approvals, for a project phase subject to this subpart, a currently conforming transportation plan and TIP must be in place at the time of project approval as described in §93.114, except as provided by §93.114(b).

(d) Grace period for new nonattainment areas. For areas or portions of areas which have been continuously designated attainment or not designated for any NAAQS for ozone, CO, PM10, PM2.5 or NO2 since 1990 and are subsequently redesignated to nonattainment or designated nonattainment for any NAAQS for any of these pollutants, the provisions of this subpart shall not apply with respect to that NAAQS for 12 months following the effective date of final designation to nonattainment for each NAAQS for such pollutant.

[62 FR 43801, Aug. 15, 1997, as amended at 65 FR 18918, Apr. 10, 2000; 67 FR 50817, Aug. 6, 2002; 69 FR 40072, July 1, 2004; 70 FR 24291, May 6, 2005; 73 FR 4439, Jan. 24, 2008]