Frequent Questions about General Conformity
Answers to the following questions can be found by scrolling down or by clicking on the question of interest. If you need further information, please use the contact information provided.
The General Conformity Rule ensures that federal actions comply with the national ambient air quality standards. In order to meet this Clean Air Act requirement, a federal agency must demonstrate that every action that it undertakes, approves, permits or supports will conform to the appropriate state implementation plan (SIP).
EPA first issued the General Conformity Regulations in 1993. Since that time, several federal agencies have shared suggestions with EPA regarding ways to improve the General Conformity Regulations. Based on these suggestions and input from states and the public, EPA revised the General Conformity Regulations in an April 5, 2010, Federal Register notice.
Currently, the General Conformity Rule applies to all federal actions that are taken in designated nonattainment or maintenance areas. However, there are three exceptions:
- Actions covered by the transportation conformity rule;
- Actions with associated emissions below specified de minimis levels; and
- Other actions which are either exempt or presumed to conform.
Federal Actions that are exempt from the General Conformity Regulations include:
- Actions covered by transportation conformity,
- Actions with emissions clearly at or below de minimis levels,
- Actions listed as exempt in the rule, or
- Actions covered by a Presumed-to-Conform approved list.
A state implementation plan is developed in order to improve or maintain air quality in designated nonattainment and maintenance areas. Through this plan, states propose their strategy for reducing criteria air pollutant emissions. Plans often incorporate different strategies, such as the use of control measures to ensure that power plants, factories and other pollution sources meet state clean air goals.
Working with EPA, states and cities also implement national programs to further reduce emissions of criteria air pollutants from sources such as cars, fuels, industrial facilities, power plants, and consumer/commercial products.
In an area without a State Implementation Plan (SIP), a federal action can be shown to "conform" by demonstrating there will be no increase in emission in the nonattainment or maintenance area from the federal action that could cause new violations of the standards and/or no increase in the frequency or severity of previous violations.
In an area with a SIP, conformity can be demonstrated in one of four ways:
- Showing that the emission increases caused by an action are included in the SIP,
- Demonstrating that the state agrees to include the emission increases in the SIP,
- Offsetting the action’s emissions in the same or nearby area,
- Mitigation to reduce the emission increase, or in some circumstances,
- An air quality modeling demonstration.
Emissions excluded from a conformity determination include those subject to New Source Review; those covered by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or other environmental laws; actions not reasonably foreseeable; and those for which the responsible agency has no ability to exercise continuing program responsibility.
Under the existing regulations, de minimis emission levels are listed for each criteria pollutant. Annual emission rates per calendar year are used. You may want to view a listing of de minimis emission levels for each criteria pollutant.
In creating the de minimis emission levels, EPA sought to limit the need to conduct conformity determinations for actions with minimal emission increases. When the total direct and indirect emissions from the project/actions are below the de minimis levels, the project/action would not be subject to a conformity determination.
Nonattainment means that an area has monitored air quality that does not meet the National Ambient Air Quality Standards (NAAQS).
The Clean Air Act (CAA) identifies six common air pollutants that are found all over the United States. These pollutants can injure health, harm the environment and cause property damage. EPA calls these pollutants criteria air pollutants because the agency has developed science-based guidelines as the basis for setting permissible levels. Ozone is a criteria pollutant. There is a NAAQS for each of the criteria pollutants. These standards apply to the concentration of a pollutant in outdoor air. If the air quality in a geographic area meets or measures less than the national standard, it is called an attainment area; areas that don't meet or exceed the national standard are called nonattainment areas.
In order to improve air quality, states must draft a plan known as a State Implementation Plan (SIP) to improve the air quality in nonattainment areas. The SIP outlines the measures that the state will take to improve air quality. Once a nonattainment area meets the standards and additional redesignation requirements in the CAA [Section 107(d)(3)(E)], EPA will designate the area as a "maintenance area."
For more information regarding the designations process, visit EPA's criteria air pollutants website and select the designations for the pollutant(s) you are interested in.
At present, there are guidance documents concerning the current General Conformity Regulations.
For more information on General Conformity, please visit the Contact Us page. To learn more about how General Conformity affects your area, contact your local or state air quality office or regional EPA office.