General Conformity Training Module 3.1: Applicability Analyses

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

3.1.1 Nonattainment and maintenance areas

The General Conformity program helps control emissions of all the criteria air pollutants defined by the National Ambient Air Quality Standards (NAAQS) or their precursors, and then only when those emissions are caused by Federal actions that would, if implemented, include activities, such as construction activities, that would originate within nonattainment or maintenance areas. Emissions that would originate within attainment or unclassified areas are not required to be evaluated for conformity. This does not include areas that the EPA redesignated from nonattainment to attainment, which are maintenance areas. Emissions of the criteria or precursor pollutants that "drift on the wind" and impact a nonattainment or maintenance area are not subject to General Conformity.

The official record of a particular area’s attainment status is in Title 40 of the Code of Federal Regulations, part 81. EPA periodically revises the designations or classifications of such areas by publishing the revisions in the Federal Register. In addition, EPA makes the attainment status of areas available by maintaining the EPA Green Book website. Specific details about a nonattainment or maintenance area can also be obtained by contacting the State, Tribal, or local air quality agency responsible for the area. Additional assistance may be obtained at the EPA Regional Office. The list of EPA’s Regional Offices is available on the General Conformity website under "Contact Us."

The delineated geographical boundaries of nonattainment and maintenance areas are generally defined in the documentation approving the designations. In most cases the boundaries are political boundaries such as county lines or are physical features (such as streets or rivers). However, in some cases the boundaries may not be well defined. For coastal areas, EPA interprets the nonattainment or maintenance area boundary to extend to the State’s Seaward Boundary (SSB), which for most of the United States, is 3 miles. The exceptions are Florida and Texas, where the boundary is 3 leagues, approximately 9 miles. Federal agencies should consult with the State, Tribal or local air quality agency to identify the boundaries of nonattainment or maintenance areas along coastlines.

The designation of nonattainment, nor the classification of, for example, a Serious ozone nonattainment area, does not define the vertical extent of the nonattainment area. Some Federal activities involve emissions from aircraft operating at various elevations above ground level. For these sources, the area’s meteorological mixing height is used as the upper limit of emissions discharges that could influence ground-level pollutant concentrations; however, the mixing height is not constant across all States and Tribal areas and varies with meteorological conditions. If a specific mixing height is not defined by the State or Tribal air agency, EPA recommends that Federal agencies use an average mixing height or a default height of 3,000 feet above ground level. Federal agencies should consult with the State or Tribal air agency to define the mixing height, which plays a role in the calculation of annual emissions generated by airborne sources.

In conjunction with nonattainment and maintenance areas, EPA also designates States that are within an ozone transport regions (OTR). At the present time, EPA has established one OTR, which extends from Northern Virginia to New England. The purpose of the OTR is to coordinate the control of ozone precursors across the OTR. To that end, EPA established special requirements for activities that cause emissions to originate within the OTR. For example, EPA has established progressively lower annual de minimis emissions threshold rates for Moderate (100 tons/year), Serious (50 tons/year), Severe (25 tons/year), and Extreme (10 tons per year) ozone nonattainment within the OTR. Further information can be obtained from the Ozone Transport Commission, the individual states or EPA Regional Offices in Boston, New York and Philadelphia.

On occasion, Federal agencies propose to authorize activities that will cause emissions to originate in more than one nonattainment or maintenance area. For example, the proposed expansion of an airport that crosses the boundary between two areas. In this case, a General Conformity evaluation must be prepared separately for each area. Emissions caused by the activities are estimated for each area and compared with the de minimis threshold rates assigned for each area. If necessary, the Federal agency must demonstrate that for each area that equals or exceeds the de minimis thresholds, the emissions conform with the applicable implementation plan. Although each area is evaluated separately, the Federal agency can combine the reporting and public notification process, provided the agency publishes notices in each local area affected, and notifies all impacted States and Tribes.

3.1.2 Transportation projects

Federal projects, plans, and programs covered by Transportation Conformity are exempt from the General Conformity requirements. It is possible that an activity proposed for a General Federal action would be subject to the requirements of the Transportation Conformity Regulations. For example:

The local Airport Authority is seeking approval from the Federal Aviation Administration (FAA) to expand and improve the airport. Part of that proposal includes a new ramp providing a connection and access to a Federal highway. Construction and operation of the ramp will be funded under the Federal Transit Act and the construction emissions and emissions from the vehicles operating on the ramp must be included in the area’s transportation plan or program. Therefore, construction and operation of the new ramp is exempt from the requirements of the General Conformity requirements. The Federal agency should coordinate with the local Metropolitan Planning Organization (MPO) to ensure the ramp project will be evaluated under Transportation Conformity. If not, the construction and operation of the ramp must be included in the General Conformity evaluation.

3.1.3 Exempt and presumed to conform activities

The EPA has identified a number of activities that cause annual emissions that would be below the de minimis rates (Module 2.1) or are otherwise presumed to conform (PTC). The EPA lists the PTC activities in the regulations, and identifies any guidance (i.e., qualifying conditions that must be fulfilled) required before a Federal agency can claim an exemption. Federal agencies can also develop their own list of PTC activities. The development of such a list is discussed in Module 3.4. Questions about the exemptions should be addressed to the General Conformity contact in the EPA Region where the emissions are proposed to occur.

3.1.4 Conformity on Tribal lands

Under the Clean Air Act, Federally recognized Indian Tribes are treated the same as States. Therefore, EPA has made a provision in the General Conformity regulations for the Tribal authority to review and comment on the draft demonstrations applicable within the nonattainment or maintenance areas where the Tribal land is located.

In most cases for Tribal lands, the Tribe has developed a Tribal implementation plan (TIP) for the area or EPA has promulgated a Federal implementation plan (FIP) for the area. These plans generally take precedence over any State implementation plan (SIP) for the area. Federal agencies should consult with EPA regional General Conformity contacts about the applicable plan for Tribal lands.

Where EPA has approved a TIP, the Tribal authority can provide documentation that the emissions for the proposed activity are included in the TIP or can commit to including the emissions in existing or future TIPs. For the Tribal areas where EPA has not approved the TIP and has promulgated a FIP for the area, EPA will perform those functions. Questions concerning the authority for TIP statements should be addressed to EPA’s regional General Conformity contacts.

3.1.5 Grace period for new nonattainment designation

The General Conformity regulations allow a one-year grace period before the conformity requirements apply to the area after the area is newly designated as nonattainment. When EPA publishes the designation of nonattainment for an area, it also identifies an effective date of the designation. The requirements of General Conformity apply one year after the effective date of the designation. Activities proposed for implementation before that date do not have to meet the General Conformity requirements. However, activities proposed for implementation on or after that date will have to meet the General Conformity requirements for the area’s new designation. Changes in an area's nonattainment classification is not a new designation, therefore there is the one-year grace period does not apply to reclassifications. Likewise, where a new NAAQS (e.g. a new concentration level) is published by EPA for an area found to continue to be nonattainment under the revised NAAQS, there is no grace period

3.1.6 Revisions to the General Conformity Regulations

When EPA revises its General Conformity regulations, it also identifies an effective date for those revisions. Usually, the effective date of the regulations is 30 to 60 days after the publication of the final rulemaking in the Federal Register. Activities that would be implemented before the effective date of the regulatory revisions do not have to meet the General Conformity requirements. However, activities that would be implemented after the effective date of the revisions will have to meet the General Conformity requirements.