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General Conformity

General Conformity Training Module 3.5: Demonstrating Conformity

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

To conform, the total direct and indirect emissions caused by the action must be in compliance or consistent with all relevant requirements and milestones contained in the applicable SIP/TIP. These requirements and milestones include reasonable further progress schedules, assumptions specified in the attainment and maintenance demonstration, prohibitions, numerical emission limits and work practices. For example, some SIPs include construction work practices to control the emission of fugitive dust or prohibition of open burning in the nonattainment or maintenance area. Federal agencies should coordinate with the state, tribal, or local air quality agency to ensure that the emissions comply with this provision.

The method for determining conformity depends upon the pollutant and the circumstances surrounding the federal action. Most conformity demonstrations either mitigate the emission increases or demonstrate that the emissions have been or will be included in the SIP/TIP. Where EPA has not approved a SIP/TIP for the area, federal agencies can demonstrate conformity by conducting an air quality modeling study for pollutants other than nitrogen dioxide and ozone. Federal agencies can use a combination of methods to demonstrate conformity for an action. Regardless of the method or methods used to demonstrate conformity, the demonstration must address all the emissions increases caused by the action and not just the emissions above the de minimis levels.

The rule requires that conformity be analyzed for emission scenarios that are expected for each of these cases:

  • The Clean Air Act mandated attainment year;
  • The last year for which emissions are projected in a maintenance plan;
  • The year with the greatest total direct and indirect emissions; and
  • The year the applicable SIP/TIP specifies an emission budget.

A federal agency can demonstrate conformity either on a worst-case basis or on a year-to-year basis. Under the worst-case basis, the agency would show that the maximum emissions conform for each of the applicable years listed above. Under the year-to-year basis the agency would show that the emissions would conform each year. The agency could use a combination showing conformity year-to-year for one phase of the action and show that the maximum emissions during another phase would conform.

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3.5.1 Mitigation of emissions

To mitigate the emission increases, the federal agency either reduces like emissions at the facility or in the same nonattainment or maintenance area. Emission reductions secured at other facilities are known as offsets. Mitigation measures need not be in place at the time that the conformity determinations are made. However, the measures must be described in detail in the conformity demonstration, including the process for implementation and enforcement, an explicit implementation schedule, written commitments for mitigation, and conditions on the approval of the action requiring implementation of the mitigation measure. Mitigation measures must be in place before emissions from the action start. The emission reductions used as mitigation measures must be (1) quantifiable, (2) consistent with the applicable SIP/TIP, (3) surplus to required emission reductions, (4) enforceable at both the state and federal levels, and (5) permanent within the timeframe specified by the program.

  • The mitigation measures are quantifiable if they can be reliably calculated and if the method of calculation can be replicated. The federal agency would need to provide to the state air quality agency sufficient data and information to enable the agency to replicate the calculations if it chooses to do so.
  • The mitigation measures would be consistent with the SIP/TIP if they are not prohibited and do not interfere with other measures in the SIP/TIP. For example, a SIP/TIP may include requirements on certain work practices, therefore if the mitigation measures involve those practices, then they would have to be consistent with those requirements.
  • The mitigation measures and their emission reductions must be surplus, i.e., they cannot be required by any other federal, state, tribal or local environmental regulations, even if the measures are not specified on the SIP/TIP. However, early implementation of a measure could produce a temporary mitigation measure. For example, if the SIP/TIP required the implementation of a measure in three years and the source implements the measure after one year, then a federal agency could use the emissions reduction for the 2-year period until it is required by the SIP/TIP. Such measures may be useful for offsetting short-term emissions, such as from a construction project.
  • The mitigation measure must be enforceable at the federal and state levels. The mitigation measure would generally be considered enforceable if they meet all of the following requirements:
  • The measures are independently verifiable;
  • A complete schedule to implement and verify approved measures has been adopted by the agency or a project proponent;
  • Violations of mitigation measure requirements are practicably enforceable in accordance with the Clean Air Act and EPA regulations; and
  • Liability for violations can be identified.

To make a measure enforceable, federal agencies may seek to have the measure included in the SIP/TIP or in a state, tribal or local air quality permit.

  • Emission reductions from the mitigation measure are considered “permanent” if they continue to occur at the estimated level throughout the lifetime of the emissions increases caused by the action. Some measures inherently produce permanent emission reductions by design, such as infrastructure improvements, while other measures can produce permanent reductions if the equipment is used and maintained, such as the use of low emission vehicles. In the case of measures that require maintenance, the federal agencies are expected to require that the equipment be maintained and used for their useful life at the facility for which they were purchased. The same emission reductions cannot be used to mitigate more than one action, i.e., there can be no double counting of the reductions.

The General Conformity Regulations allow federal agencies to obtain offsets from not only the nonattainment or maintenance area where the action occurs, but also adjacent areas of equal or higher classification provided the emissions from that area would affect the area with the action. Generally, this may be done by showing that the general wind flow patterns would move the precursors of the pollutant into the area. However, for some primary pollutants (pollutants emitted directly into the atmosphere), this may require some air quality modeling.

To facilitate the availability of mitigation measures, EPA included in the regulations a provision for emission reduction credits (ERCs). Under this program, federal facilities would institute measures to reduce emissions and work with the state, tribal or local air quality agency to receive credit for those reductions towards future conformity evaluations. The requirements for the creation and use of the ERCs are discussed in a separate section.

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3.5.2 Conformity with SIP or TIP

For any criteria pollutant, conformity can be demonstrated by showing through existing documentation that the total direct and indirect emissions caused by the action are specifically identified and accounted for in the SIP/TIP. Since states, tribes and local air quality agencies may not be aware of future federal actions at the time of the SIP/TIP development, few federal actions requiring conformity have their emissions specifically identified and accounted for in the SIP/TIP. Where the actions are specifically identified and accounted for in the SIP/TIP, the conformity demonstration can be easy and straightforward – the federal agency would only have to document the information in the SIP/TIP.

In the cases where the emissions caused by the action are not specifically identified in the SIP/TIP, but are included in an emission budget category, the federal agency can demonstrate conformity by having the applicable state, tribal or local air quality agency provide a written statement documenting that the emissions caused by the action along with all other emissions in the area will not exceed the budget for those emissions in the SIP/TIP. For example, a state could document that when the emissions from the construction phase of the action are combined with the emissions from all other construction activities in the area, the total will not exceed the SIP/TIP budget for construction emissions. In the case of vehicle emissions, the federal agency can obtain a statement from the appropriate Metropolitan Planning Organization (MPO) responsible for transportation planning in the area that the direct or indirect vehicular emissions caused by the action, or a portion thereof, are included in a conforming transportation plan and transportation improvement program.

3.5.3 Conformity without a SIP or TIP

Federal agencies have three options to demonstrate conformity in areas without an approved SIP/TIP or with a SIP/TIP that does not cover the time period of the projected emissions.

  • First, they can mitigate the total direct and indirect emissions from the action.
  • Second, they can make a modeling demonstration that the emissions will not cause or contribute to a new or existing violation of the standard, interfere with the timely attainment or maintenance of the standard.
  • Third, they can have the state or tribe commit to include the emissions into the future SIP/TIP for the area. Each method is further discussed below.

The mitigation of the emissions needs to meet the requirements for mitigation measures and offset discussed in section 3.5.1.

For primary pollutants, conformity can be demonstrated through the use of air quality modeling. Localized pollutants such as CO and PM 10 are typically subject to modeling that must demonstrate that the emissions from the action will not cause or contribute to an increase in the severity or frequency of NAAQS violations. The modeling must be conducted in accordance with EPA’s Guidelines for Air Quality Modeling (70 FR 68218). The state or tribal agency will determine whether local-, area-wide, or both types of modeling are appropriate. Therefore, before a federal agency proceeds with a modeling demonstration, it should discuss the protocol with the state, tribal, or local air quality agency and the EPA regional Office. Modeling demonstrations are not permitted for secondary pollutants (pollutants formed in the atmosphere) such as ozone, nitrogen dioxide, and fine particles.

Finally, the federal agency can work with the state or tribe and obtain a written commitment from the Governor, or the Governor’s designee for SIP or the tribal leader for TIP, to include the emissions in the SIP/TIP. If the emissions would occur during the time-period covered by an existing SIP/TIP, the regulations would treat this written commitment as an automatic call for a SIP/TIP revision, which must be submitted within 18 months. If the emissions would occur beyond the period covered by the SIP/TIP, then the state or tribe must submit a SIP/TIP revision committing to include the emissions in the future SIP/TIP when it is adopted.

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3.5.4 Schedule for demonstration measures

The conformity demonstration must include a schedule for the adoption and implementation of the mitigation measures. Although the measures do not have to be in place at the time the conformity demonstration is finalized, the measure must be described in detail, a schedule for adoption and implementation must be included and the measures must be in place before any activities resulting in increase emissions commence. For example, if the emissions from construction activities are to be offset by using alternative fueled vehicles, then the vehicles must be in operation before the construction starts. The federal agency can develop a phase program to mitigate the emissions where the quantity of the offsets varies over time.

In general, the annual emission reductions from the mitigation measures must exceed the emission increases caused by the action. However, under certain conditions, federal agencies can negotiate with the state or tribe and EPA to create an alternative schedule that allows the federal agency to offset the emission increases over a longer time period. For example, the federal agency could adopt measures that reduce emissions by 100 tons per year over a 20-year period to offset an emission increase of 130 tons per year for 10 years. The regulations place two major restrictions on the use of this option. First, the total emission reductions must exceed total emission increases as follows:

Extreme areas 1.5:1

Severe areas 1.3:1

Serious areas 1.2:1

Moderate areas 1.15:1

All other areas 1.1:1.

Second, the time period for the reductions to compensate for the increases cannot exceed two times the period of time that the emissions result from the action. For example, if the mitigation measure is to offset construction emissions and the construction will take three years, then the mitigation must be completed in six years. In addition, the state or tribe is not relieved from any of its obligations to meet milestones or attainment deadlines. Therefore, the state or tribe must agree to the additional time for mitigation and it must be able to demonstrate that all relevant SIP/TIP requirements will be met during the period of increased emissions. The participation of the state or tribe is voluntary; they are not obligated to approve the additional time even if all requirements are met.

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3.5.5 Enforcement of mitigation measures

There are several methods to ensure that the mitigation measures are enforceable by EPA and the state or tribe. Two of the most common are:

  • For the state, tribal, or local air quality agency to include the emissions in the SIP/TIP; or
  • For the state, tribe or local agency to issue a permit for the emissions under an approved SIP/TIP permitting program.

If the mitigation measures are not being implemented, the state, tribe or local agency and EPA will, in most cases, take enforcement action against the organization responsible for the emission reductions. For example, if the federal agency secures an emission offset from a local power plant, and that reduction is included in the SIP or an air quality permit but the power plant fails to implement the measures to produce the reductions, EPA would normally take action against the local power plant and not the federal agency.

3.5.6 Modification of mitigation measures

If a federal agency wants or needs to modify or replace a mitigation measure used in a conformity demonstration, it must demonstrate that the modified or substitute measure will provide the same level of reduction provided by the original measure. Any modified or substitute measure must receive the same the interagency and public review as required for a draft conformity demonstration.

3.5.7 Alternative approaches Emission reduction credit program

The emission reduction credit (ERC) program is a joint effort between the federal facility and the state or tribe. Neither party is obligated to participate but both must participate in order for the program to be established. Therefore, a discussion between the parties before initiating action on the program would be prudent.

Under the program, the federal facility would identify a measure to reduce emissions. To receive credit for the measure, it has to meet the same criteria as an emission offset, i.e., it must be quantifiable, consistent with the applicable SIP/TIP, surplus to required emission reductions, enforceable at both the state and federal levels, and permanent within the timeframe specified by the program. In addition, EPA requires that the measure be adequately supported, meaning that the federal facility can demonstrate that sufficient resources are available to properly implement the measure.

The federal facility would present the information about the potential ERC to the state, tribal or local air quality agencies to determine the quantity of credits available for the measure. The state or tribe would provide the federal facility with a written estimate of the available ERCs from the measure. The federal facility would then implement the measure.

In some cases it may not be possible to reasonably estimate the emission reductions from innovative measures in advance. In such cases, the federal facility could implement the measure along with a monitoring program to determine the quantity of ERCs that could be created by the measure.

When the federal facility needs to conduct a conformity evaluation, it can request the state to grant the ERCs for the measure and use the reductions to determine the net total direct and indirect emissions from the action. The ERC measure would be considered as part of the design of the action.

The ERCs are only the emission reductions that occur during the year of their use. The reductions cannot be rolled over from one year to the next. State, tribal and local agencies can develop their own system for reviewing and granting ERCs. Facility emission budget approach

The facility emission budget approach is also a joint effort between the federal facility and the state or tribe. Neither party is obligated to participate but both must participate in order for the program to be established. Therefore, a discussion between the parties before initiating action on the approach would be prudent.

This approach is designed for a federal agency that takes multiple actions at a facility. Under the approach the federal agency and the state, tribal or local air quality agency would determine an emission budget for the facility. The budget would be used in development and adoption of the SIP/TIP for the area. As long as the federal facility remained within the emission budget, no conformity evaluation would be necessary for any actions affecting the facility.

To initiate the emission budget process, the federal agency would develop an emission inventory for the facility. Once the budget has been established, the federal agency could develop programs to reduce emissions at the facility and document the reduction against the base inventory. This would allow the federal agency to take additional actions without the need to address conformity if the emissions increase from the actions did not cause the facility's emissions to exceed the budget.

If the federal agency wants to take an action at the facility that would cause the emission from the facility to exceed the emission budget for the facility, then it would be required to conduct a standard conformity evaluation.

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3.5.8 Special Situations Prescribed and wild fire policy

Under the EPA regulations, responses to wildfires are considered emergency actions and, as such, are exempt from the conformity requirements. In some areas federal agencies have policies to let wild fires burn through wilderness areas and do not suppress the fires unless it moves out of the designated area. Such actions would be covered under the federal agency’s response to an emergency and the agency would not have to conduct a conformity evaluation unless the burn continues beyond six months.

Prescribed fires, on the other hand, may require a conformity evaluation. If the prescribed fire is conducted in accordance with a smoke management plan, it is presumed to conform and no conformity determination is necessary. Generally, if the prescribed fire is not part of a smoke management plan a conformity evaluation would be required by the federal agency. The use of basic smoke management practices for some prescribed fires may be added to a federal agency or state and tribes presumed-to-conform list through the procedures established in the conformity regulations. One of the criteria that federal agencies can use as a basis for a conformity determination is inclusion of the activity in the SIP/TIP. If the SIP/TIP includes emissions from prescribed fires, then the federal agency can rely on a state or tribal statement that the emissions are accounted for in the attainment demonstration.

If the prescribed burning program is part of an ongoing program where there are a set number of acres burned per year in the same general geographic area, an action to continue the program at or below the existing level would be considered continuation of a routine activity. However, if there are prescribed burning goals in a land management plan without a specific program of ongoing burns, or if the prescribed fires occur in a different geographic area, the action may not be continuing or recurring, and the federal agency may be required to conduct a conformity evaluation. EPA water projects

The EPA’s action to award the State Revolving Funds capitalization grant is considered a programmatic level decision whose emissions are not reasonably foreseeable and thus a conformity evaluation is not necessary. However, if the grant is for a specific project then a conformity determination is required.

If the action involves a regional wastewater project and the project is sized to meet only the needs of population projections that are in the applicable SIP/TIP, then the project conforms. However, if the current population projections used for the project are greater than those in the approved SIP, then one of the other criteria must be used to demonstrate conformity. Conformity when the SIP or TIP is under revision

Federal agencies on occasion take actions in areas where the state, tribe or local air quality agency is in the process of revising the SIP/TIP. The federal agency must demonstrate conformity to the EPA approved SIP/TIP even if the state, tribe, or local agency is in the process of revising it. However, if the state or tribe is expected to submit the revised SIP/TIP to EPA within 18 months, then the federal agency could work with the state to include the emissions in the new plan and demonstrate conformity through the state or tribe commitment approach. The state or tribe would then submit a SIP/TIP revision committing to include the emissions in the future SIP/TIP. Conformity for rulemaking actions

The rulemaking process itself is exempt from the General Conformity Regulations. However, if an agency promulgates a rule that increases emissions in any nonattainment or maintenance area, the rule's substance itself must be evaluated for conformity. If the emissions in any area would exceed the de minimis levels for the area and the action is not otherwise exempt, then the agency must demonstrate conformity.

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