General Conformity Training Module 1.1: What and Where

Words that are shown in bold and italics are defined in the Glossary.

EPA maintains a General Conformity website https://epa.gov/general-conformity.

1.1 What is General Conformity?

General Conformity is the process through which a federal agency must assure the State or Tribal air agency that the activities the agency proposes to fund, permit or license, or approve conforms to applicable implementation plan, and that the emissions caused by such activities will not interfere with the State's or Tribe's ability to attain and maintain the National Ambient Air Quality Standards (NAAQS), which are established by the EPA to protect human health and the environment. It is the responsibility of the State to attain the NAAQS within a nonattainment area by the statutory attainment date and maintain attainment of the standards once the area is re-designated attainment, referred to as a maintenance area. Such areas are under the State's and Tribe's jurisdiction and authority and sanctions could be imposed for a failure to attain the NAAQS in a timely manner.

The General Conformity program requirements are established at 40 CFR part 93 subpart B and implements the Clean Air Act (CAA) conformity requirement under section 176(c)(4)(A) for general Federal activities. There may be several federal activities subject to the conformity requirement that are considered together in an agency's larger National Environmental Policy Act (NEPA) environmental assessment (e.g., EIS, EA). Not every NEPA Environmental Impact Statement (EIS) or Environmental Assessment (EA) requires a General Conformity evaluation, but nearly every General Conformity evaluation prepared is intended to support a NEPA review that assesses the overall environmental impact of the proposed project.

1.1.1 Applicable Implementation Plan. Each nonattainment area and re-designated attainment area (i.e., maintenance area) operates under a uniquely applicable air quality Implementation Plan developed either by the State (State Implementation Plan, or SIP), the Tribe (Tribal Implementation Plan or TIP), or the EPA (Federal Implementation Plan or FIP). A SIP or TIP must be approved by EPA before use in evaluating General Conformity. An applicable implementation plan contains the procedures, regulations, and documents that federal agencies and non-federal entities must abide by in order to enable the State or Tribe to attain the National Ambient Air Quality Standards (NAAQS) or maintain the NAAQS within a maintenance area. The State or Tribe has the jurisdiction and authority to implement, maintain, and enforce the NAAQS through their implementation plans and to fulfill other requirements of the CAA. Under General Conformity, a federal agency must assure conformity of their project's emissions to the implementation plan's purpose of eliminating or reducing the severity and number of violations of the NAAQS and achieving expeditious attainment of the NAAQS.

1.1.2 Applicability Analysis. The General Conformity applicability analysis includes a screening analysis and, if needed, a net emissions analysis. The screening analysis allows the federal agency to exclude from consideration any federal activities causing emissions that the EPA considers as Presumed to Conform (PTC), exempt, or are otherwise not applicable under General Conformity. General Conformity applicability requires that one or more applicable activities must cause emissions of the criteria pollutant for which the affected nonattainment or maintenance area was designated nonattainment (and includes precursor pollutants), and the emissions must originate within the affected nonattainment or maintenance area. The emissions from the remaining activities that cause such emissions are calculated on an annual basis, by pollutant, and each year's emissions, by pollutant, are compared to the projected emissions of the same pollutants from existing sources occurring within the same affected area for the same future years. The results are compared to the appropriate annual de minimis threshold rates for those pollutants. This applicability process will identify for the federal agency which of their project's net emissions require more rigorous investigation, meaning---

If the annual net emissions of all relevant pollutants indicate no increase or an increase that is less than the de minimis rates established by the EPA for those pollutants, no further evaluation is required under General Conformity; or
If the annual net emissions of any pollutant indicate an increase that would equal or exceed one or more of the de minimis rates established by the EPA for that pollutant, the federal agency must develop one or more strategies to reduce, eliminate, or offset the net increase, so that the activities' emissions have the effect of a zero net emissions increase. Such strategies must be in place before the proposed activities can be funded, permitted or licensed, approved, or implemented by the federal agency or the non-federal project sponsor.

Thus, emissions that may be excluded from the applicability analysis, including activities that:

Affect the use or operation of vehicles, buses, and other mobiles sources operating on federal highways (activities subject to Transportation Conformity);
Cause no emissions or only a small increase in annual emission rates, which are activities the EPA lists under General Conformity as exempt, and such activities are specifically identified in the federal agency's project scope of work or plan to meet the characteristics as described for such an exemption;
Cause annual net emissions increases that are less than the de minimis threshold rates, as calculated by the federal agency for their current project and are therefore presumed to conform;
Are identified by EPA in the General Conformity regulations to be presumed to conform;
Are presumed to conform, as listed in the agency's own published list of PTC activities, or listed in the State's or Tribe's General Conformity implementation plan revision as PTC; and
Are specifically identified in the regulations as exempt.

1.1.3 General Conformity Determination. For any years that any pollutant emissions equal or exceed the de minimis rates, the federal agency must perform an analysis (i.e., General Conformity demonstration) that explains how the federal agency will assure conformity to the applicable implementation plan. The agency must then prepare its General Conformity Determination, which is a signed statement affirming that based on its demonstration of conformity, their project's activities that require their assistance to fund, permit or license, approve, or approve implementation conforms to the applicable implementation plan as specified under CAA section 176(c)(1)(A) and (1)(B).

1.2 Where does General Conformity apply?

General Conformity applies within nonattainment and maintenance areas. A nonattainment area is an area designated by EPA as consistently violating a NAAQS. A maintenance area is an area that was once designated nonattainment but is currently meeting and maintaining the standard and operating under a "maintenance plan," hence the name "maintenance area." EPA, in partnership with the States, is responsible for the designation of areas as nonattainment and redesignating them once they achieve the NAAQS. Information on where nonattainment and maintenance areas are located can be found on EPA’s Green Book website. On the site, you can search by pollutant, designation status, or county. You can also contact your EPA Regional office for more information on nonattainment and maintenance areas in your state.

1.3 How to conform and who is responsible?

Conformity means that a federal agency has met all the requirements of subpart B and can assure the State that its proposed project meets (conforms to) the purpose of the State's air quality prevention and control plans for attainment and maintenance of the NAAQS. This assurance is the responsibility of the federal agency or agencies proposing to approve, fund or permit the Federal activities described in the project plan.

Under CAA section 176(c)(1)(A) and (1)(B), a federal agency must conform to the purpose of the applicable SIP, meaning that the proposed Federal activities will not cause any new violation of the NAAQS, increase the frequency or severity of any NAAQS violation, or delay timely attainment of the NAAQS or interfere with any interim milestones or schedules. If necessary, Federal activities must conform to the applicable Tribal implementation plan (TIP) developed by eligible tribes or the applicable Federal implementation plan (FIP) developed by the EPA.

1.4 When are Federal activities subject to General Conformity?

General Conformity covers a wide variety of federal activities. Federal activities are tasks that are needed to ensure successful implementation or operation of a federal project (e.g., construction phases, operational phases, operation of additional aircraft for an airport improvement project, decommissioning of a facility, etc.). When Federal activities require assistance from a federal agency, such as approval, funding or a permit, and those activities cause emissions of criteria or precursor pollutants within a nonattainment or maintenance area, the activities are subject to the General Conformity provisions. An applicability analysis is required at minimum, and the General Conformity Determination, if needed, must be completed before the federal agency, the non-federal entity it supports, or their contractors can engage in or implement the activities. Such assistance may be approval of the project plan that includes, among other things, all the Federal activities that are subject to General Conformity, funding of part or all of the project, or issuing a permit or license required by another agency cooperating with the NEPA review (e.g., an EPA air permit for an airport project, a FWS wetland rehabilitation permit within a larger construction project, etc.). Usually, implementation of Federal activities cannot commence, and permits do not come into play, until the larger project plan is approved, or funding is provided through the agency's federal action to issue the NEPA Record of Decision (ROD) or the agency's NEPA Finding of No significant Impact (FONSI).