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General Conformity

General Conformity Training Module 1.3: Background

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

1.3.1 Why Congress added General Conformity to the CAA 

In 1977, Congress recognized that a number of federal actions could interfere with the state and local governments’ ability to attain the NAAQS. For example, federal decisions on highway funding or the realignment of military bases could significantly affect the emissions in nonattainment and maintenance areas. To ensure that the federal government was not interfering with the state attainment planning process, Congress added section 176(c) to the CAA (codified in section 7506). This section prohibits federal agencies from taking any action which does not conform with the SIP to attain and maintain the NAAQS. However, the EPA interpreted this section as only addressing transit and highway-related projects. In the CAA Amendments of 1990, Congress revised section 176(c) to clarify that it applied to all federal actions, not just to actions related to highways and mass transit.

1.3.2 Legal requirement for conformity

The legal requirement for the General conformity program is found in section 176(c) of the CAA. The CAA, as amended in 1990, prohibits departments, agencies and other instrumentalities of the federal government from taking any action which does not conform with the SIP. As a result, EPA, in 1993, promulgated two new sets of regulations. The transportation conformity regulations address actions taken under the Federal Highway Administration or Federal Transit Administration programs. All other actions are addressed by the General Conformity Regulations that were first promulgated on November 30, 1993 and codified as 40 CFR 93.150 and 40 CFR 51.851 et seq (58FR63214).

1.3.3 Air Quality Management National Ambient Air Quality Standards (NAAQS)

In order to protect public health and the environment, EPA has established NAAQS for six criteria pollutants. These pollutants are found throughout the United States and can cause significant health problems, as well as cause damage to the environment and to property. The six pollutants are particle pollution (often referred to as particulate matter), ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead. The limits established for these pollutants to protect public health are called primary standards. Limits intended to prevent environmental and property damage are called secondary standards. Designations and Classifications 

The CAA directs EPA to designate areas based on ambient air quality data and other information as to whether or not the area is attaining the standard. In addition, the CAA also requires EPA to classify areas based upon the severity of the pollution problem for certain pollutants. The CAA ties the stringency of the control measures to the area’s classification. For example, areas with higher classifications (e.g., severe) have more stringent requirements. The designation and classification of the areas are codified in 40 CFR part 81. The information on which areas are designated and their classification is available on EPA’s Green Book website. Nonattainment and Maintenance Areas

The EPA designates an area as nonattainment generally based upon air quality monitoring data or modeling studies that show the area violates, or contributes to violations of the national standard. Where the data do not make such a showing, EPA designates the area as attainment or unclassifiable. After a nonattainment area’s air quality improves so that it is no longer violating or contributing to violations of the standard, and the state or tribe adopts an EPA-approved plan to maintain the standard, EPA can redesignate the area as attainment. These areas are known as maintenance areas. Maintenance areas retain that classification for 20 years after they are designated as attainment. The CAA and EPA regulations impose special requirements to help improve and maintain the air quality of nonattainment and maintenance areas.

Top of Page State, Tribal, and Federal Implementation Plans

SIPs are developed and adopted by states and are designed to improve air quality in nonattainment and maintenance areas. State and local governments are responsible for developing and implementing the SIPs, which are submitted to EPA and, upon approval, become federally enforceable. The SIPs are documents which include area-specific information such as the existing air quality, an inventory of the emission sources, projected growth, a strategy to improve the air quality, laws and regulations needed to implement the strategy and a demonstration that the area will attain the standard. On tribal lands, federally recognized Indian tribes can develop their own TIPs similar to SIPs. If the state or tribe fails to submit a required plan, EPA can promulgate a federal implementation plan known as a FIP. Federal Compliance

Section 176(c) requires federal agencies to comply with the General Conformity Regulations and demonstrate conformity for projects in nonattainment or maintenance areas or the projects cannot proceed. Federal agencies are required to provide notice of its draft conformity determination to the EPA Regional Office, the state and local air quality agencies, federally recognized Indian tribes in the area, the local Metropolitan Planning Organization, and the local or federal land manager for a 30-day comment period. The General Conformity Regulations also require that notice of the draft conformity determination be placed in a daily newspaper in the area affected and to allow for a 30-day comment period. These notifications are also required when the federal agency makes its final conformity determination.

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1.3.4 How is General Conformity related to other programs? Transportation Conformity

Transportation conformity ensures that transportation activities meet air quality goals by only approving and funding those activities that meet those goals. Transportation conformity applies to transportation plans, transportation improvement programs, or Federal Highway Administration or Federal Transit Administration projects in areas that do not meet air quality standards for the NAAQS (i.e., nonattainment areas or maintenance areas). Project emissions subject to Transportation conformity are exempt from the General Conformity program. National Environmental Policy Act

The National Environmental Policy Act (NEPA), passed in 1969, requires federal agencies to consider how “major” federal actions, including the use of federal funds, lands, or permits, may impact the human environment. The human environment includes natural, cultural, and socioeconomic resources. NEPA also requires that decisions include public input and involvement. Additional information on NEPA can be found at

If convenient, a conformity determination may be integrated with the NEPA process. However, this is not required and the two may be separated. The federal agency determines the most appropriate way, given the individual situation, to integrate the conformity and NEPA processes. There are certain requirements for NEPA, such as the development of alternative actions, that are not required under conformity. Therefore, it may not make sense to perform a conformity analysis for all alternatives, but only for the one actually selected. At a minimum, at the point in the NEPA process when the specific action is determined, the air quality analyses for conformity should be done. Another point at which the two processes might overlap is during the joint notification and public participation process (assuring that the requirements for each regulation are met).

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