General Conformity Rule|
What is Conformity?
CAA and Conformity Terminology
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The General Conformity Rule, sometimes referred to as the Air Conformity Rule or Air Conformity, applies to all federal actions except programs and projects requiring funding or approval from the DOT, the Federal Highway Administration (FHWA), the Federal Transit Administration, or the Metropolitan Planning Organization (MPO). These types of programs and projects must instead comply with the conformity provisions implemented in the Transportation Conformity Rule issued by the DOT on 24 November 1993.
This fact sheet provides an overview of the General Conformity Rule codified at Title 40 Code of Federal Regulations (CFR) Part 51, Subpart W, and Title 40 CFR Part 93, "Determining Conformity of Federal Actions to State or Federal Implementation Plans."
The General Conformity Rule divides the air conformity process into two distinct areas: applicability, and determination, both of which are discussed in detail below. Federal agencies must initially assess if an action is subject to the Conformity Rule (Applicability Analysis) and then if the action conforms to an applicable implementation plan (Conformity Determination).
To fully comprehend the conformity process, an understanding of the language specific to the CAA and General Conformity Rule is necessary. The next page has a list of CAA and air conformity terms and definitions, which are used throughout the remainder of this fact sheet.
Criteria Pollutants - Six common air pollutants: sulfur dioxide (SO2), nitrogen oxides (NOX), carbon monoxide (CO), particulate matter (PM10), ground-level ozone (O3), and lead (Pb), designated by the EPA for which primary and secondary NAAQS have been established.
State Implementation Plans (SIPs) - Section 110 of the CAA requires each State to adopt and submit to the EPA an implementation plan that provides for the implementation, maintenance, and enforcement of NAAQS in each Air Quality Control Region.
Federal Implementation Plans (FIPs) - If a SIP is disapproved, the EPA must establish a federal plan for the State to ensure air quality is maintained and enforced in accordance with established NAAQS.
Attainment Area - Geographic area that meets the primary NAAQS established by the EPA to protect health and the environment. Note: An area may meet the established NAAQS for one criteria pollutant, but have unacceptable levels for another. Thus an area could be in attainment for one criteria pollutant and, at the same time, in nonattainment for another.
Nonattainment Area - Geographic area that does not meet the primary NAAQS limits established by the EPA to protect public health and the environment.
Note: The EPA establishes time limits for nonattainment areas to achieve specified air quality goals and may further designate nonattainment areas as extreme, severe, serious, moderate, or marginal.
Maintenance Area - Geographic area previously designated nonattainment and subsequently redesignated to attainment, for a probationary period, due to meeting the NAAQS.
Federal Action - Any action engaged in by the federal government, or any activity that a department, agency, or instrumentality of the federal government supports by providing financial assistance, licenses, permits, or approval in any way.
Direct Emissions - Emissions of a criteria pollutant or its precursor caused by a federal action which occurs at the same time/place of the action.
Indirect Emissions - Emissions of a criteria pollutant or its precursor caused by a federal action, but may occur later in time and/or may be removed in distance from the action, but are still reasonably foreseeable.
Reasonably Foreseeable Emissions - The future projected indirect emissions that have a known location and are quantifiable at the time of the conformity determination.
Regionally Significant Emissions- The total direct and indirect emissions of a federal action for any criteria pollutant which represents 10% or more of a nonattainment or maintenance area's emission inventory for that pollutant.
De Minimis Emissions - The total direct and indirect emissions of a criteria pollutant caused by a federal action in a nonattainment or maintenance area in less than specified rates. Note: Specified rates for criteria pollutants in nonattainment and maintenance areas are located in Title 40 CFR Part 93.153(b)(1) and (2).
Emission Budget - Portions of an applicable implementation plan that projects emission inventories describing the levels of emissions (mobile, stationary, or area) and provides for meeting set air quality goals for any criteria pollutant or its precursor, such as volatile organic compounds (VOCs).
Source: The definitions found here are paraphrased, and should only be used as a reference. The precise, legal definitions can be found in the Clean Air Act (CAA), 42 United States Code (U.S.C.) . 7401, et seq., Title 40 CFR Part 51, Subpart T, and Title 40 CFR Part 93.
The initial step after defining the federal action and its location is to determine if the action is exempt from a conformity determination. If a federal action takes place in a nonattainment or maintenance area and meets any of the following criteria, then the action may be classified as exempt:
Note: Even if the total direct and indirect emissions for a criteria pollutant in a nonattainment or maintenance area is below specified rates or clearly de minimis levels, the action must still be evaluated for regional significance. If the total direct and indirect emissions are found to be regionally significant, the action must undergo a conformity determination.
Aside from a federal action meeting one of the above exemption criteria, a conformity determination is not required for the following:
Actions Presumed to Conform
Under this provision of the General Conformity Rule, a federal agency may establish a list of actions presumed to conform. If an agency develops such a list, a conformity determination does not have to be conducted as long as the federal agency can clearly demonstrate that the total direct and indirect emissions from the action will not:
Note: The U.S. Air Force has not initiated or developed any listing under this provision of the General Conformity Rule. Therefore, "Presumed to Conform" categories do not exist for the Air Force.
Emission identification, analysis, and quantification are the foundation of any air quality conformity study. Studies should be based on emission calculations utilizing the methods and factors found in "Compilation of Air Pollutant Emission Factors, AP-42," Office of Air Quality Planning and Standards, Environmental Protection Agency (EPA), and not rough estimates. The following are typical Air Force activity emissions that may be involved in a conformity study:
For Air Force facilities, the Environmental Flight (EF) acts as the central organization for collecting and calculating emissions information for an action's conformity determination. The Base Civil Engineer (BCE) provides information on any construction requirements and facility maintenance; and the Bioenvironmental Engineer (BEE) provides air quality sampling techniques and baseline air quality data. There are two common tools utilized by the Air Force to aid in emission analysis, the Air Conformity Applicability Model (ACAM) and the Emission and Dispersion Modeling System (EDMS).
To properly conduct a conformity determination, the decision must be based on the latest:
Methods for Determining Conformity
An action cannot conform unless the total direct and indirect emissions for criteria pollutants from the action are in compliance with all relevant requirements contained in the applicable implementation plan. The EPA provides several methods to determine if an action conforms to an implementation plan including a State Emission Budget, Emission Offsets, and/or Air Quality Modeling. A federal agency can use one or any combination of the methods, described below, to show positive conformity.
Commitment: The State may commit in writing to the EPA, for any action in which the total direct and indirect emissions would exceed the emission budget of the applicable implementation plan:
Reporting and Public Participation Requirements
When a draft conformity determination is made, the federal agency must give a 30-day notification and provide the draft document to the EPA Region, State and local air quality agencies, any affected federal land managers, and the MPO. The federal agency is also required to make the draft conformity determination with supporting documentation, describing the methods and conclusions used in conducting the applicability analysis, available to the public for a 30-day review period.
Any comments received during the public comment period, as well as any federal agency responses must be made available to the public upon request. Also, within 30 days after the final conformity determination is made, the federal agency must notify the public, EPA Region, State and local air quality agencies, any affected federal land manager, and the MPO.
Note: Going public, or notifying the public, in this instance does not refer to publishing in the Federal Register. Federal agencies may satisfy the public notice requirement by placing an advertisement in a daily newspaper in the area affected by the action.
The conformity status of a federal action lapses 5 years from the date of the final conformity determination. Continuous federal actions do not have to be re-determined if the action is still within the scope of the final conformity determination. However, a new conformity determination is required if a federal action is altered causing an increase of the total direct and indirect emissions of the action.
In order to obtain a positive conformity determination with an applicable implementation plan, a federal agency may mitigate air quality impacts of the action. Mitigation measures are specified conditions within the conformity determination that lowers the total direct and indirect emissions of an action, thereby achieving a positive conformity. However, if all available mitigation measures are implemented and the action still has a negative conformity determination, the action cannot be implemented and may have to be altered to achieve a positive finding.
There are many mitigation measures available; however, it is up to the federal agency to select the most effective measures. Despite the type of mitigation measure intended to mitigate impacts, the measures must be identified and the federal agency must include an implementation schedule with enforcement measures in the conformity determination. Also, prior to determining conformity, the federal agency must obtain written commitments from the individuals implementing the mitigation measures.
The Air Force Conformity Process follows the federal guidelines with a few additional requirements. The Air Force requires all conformity determinations be reviewed by Headquarters U.S. Air Force Civil Engineer (HQ USAF/ILE) and approved by the Deputy Assistant Secretary of the Air Force for Environmental, Safety, and Occupational Health (SAF/MIQ). Further, Air Force facilities must contact and consult with Headquarters Air Force Center for Environmental Excellence (HQ AFCEE), with federal, State and local air quality agencies, and the MPO. Consultation with the appropriate agencies should begin once it is determined the action is not exempt or the emissions are clearly de minimis. Finally, the Air Force requires the individual Major Commands (MAJCOMs) to develop procedures to officially document exempt and clearly de minimis actions.
Interaction with NEPA
The conformity analysis may be integrated with the National Environmental Policy Act (NEPA), as conducted by the Air Force's Environmental Impact Analysis Process (EIAP). The General Conformity Rule allows for this integration; however, the extent of integration depends on the individual situation, and is ultimately determined by the federal agency. When the two are integrated, the Air Force recommends the conformity applicability analysis and determination be recorded as appendices in the NEPA document.
The two processes may be integrated for efficiency and convenience such as a combined public comment period and notification requirements; however, there are certain requirements of NEPA which are not required under the conformity rule, such as the development of alternative actions. Also, federal actions which are categorically excluded (CATEXs) under NEPA are not automatically excluded from the conformity rule; and a conformity determination only has to be conducted on the preferred alternative as indicated by the NEPA process. For additional information on NEPA and EIAP, view the PRO-ACT fact sheet, "National Environmental Policy Act (NEPA)."