Title 42 › CHAPTER 85 — AIR POLLUTION PREVENTION AND CONTROL › SUBCHAPTER I — PROGRAMS AND ACTIVITIES › Part D — Plan Requirements for Nonattainment Areas › subpart 1 — nonattainment areas in general › § 7506
Federal agencies must not fund, approve, permit, or support any activity that does not follow an approved State implementation plan (SIP) to meet air-quality standards. Metropolitan planning organizations (MPOs) also must not approve transportation plans, programs, or projects that fail to follow the SIP. Agency heads are responsible for making sure their actions conform. Conformity means the activity helps eliminate or reduce violations, does not create new violations, does not make old violations worse, and does not delay meeting required air-quality goals. Conformity decisions must use the most recent emissions estimates based on current population, jobs, travel, and congestion data. Transportation plans and projects must follow the SIP rules before federal funding or approval. A project can be treated as conforming if it comes from a conforming plan, its design has not changed much, or a project-level emissions check shows it will not make SIP emission budgets worse. MPOs must re-check conformity within 2 years after the EPA finds or approves a motor vehicle emissions budget. EPA and the Secretary of Transportation must write and update rules for making conformity decisions, including consultation steps and how often to check (at least every 4 years unless the MPO chooses more often or is required to act sooner). States had to include certain consultation and enforcement procedures in their SIPs by 2 years after August 10, 2005. Transportation control measures in a SIP may be replaced if the substitutes cut equal or more pollution, follow the same schedule, have funding and legal authority, were developed with all affected parties, and are agreed to by the MPO, the State air agency, and the EPA; once agreed, the substitutes become part of the SIP and must be sent to EPA within 90 days. If a required conformity finding is not made and the problem is not fixed within 12 months, the transportation plan lapses (meaning there is no currently conforming plan). This whole set of rules applies to areas that are nonattainment for a pollutant or areas redesignated to attainment that must keep a maintenance plan. Areas newly designated nonattainment get a 1-year delay before these conformity rules apply. Finally, federal agencies must give priority to carrying out the parts of SIPs that will help meet and keep the national air-quality standards. Definitions: SIP — State implementation plan for meeting air-quality standards. MPO — metropolitan planning organization that makes regional transportation plans. Air pollution control agency — the agency responsible for air plans in the area. Lapse — the conformity finding has expired so there is no conforming transportation plan. Conformity — activities that do not cause new violations, worsen existing ones, or delay reaching air-quality goals.
Full Legal Text
The Public Health and Welfare, Source: USLM XML via OLRC
Legislative History
Reference
Citation
42 U.S.C. § 7506
Title 42, The Public Health and Welfare
Last Updated
Sep 23, 2026
Release point: 119-110