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Air Quality Impact Analysis and Other PSD Requirements

Donald LawU.S. EPA Region 8

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• Main requirements1. Install Best Available Control Technology (BACT)2. Perform air quality analysis to assess impacts on

air quality3. Perform Class I Area analysis to assess impacts

on national parks and wilderness areas or other Class I Areas

4. Perform additional impacts analysis5. Provide opportunities for public involvement

Review: PSD Program Requirements

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• Pollutant-specific analysis that involves • An assessment of existing air quality and • Modeling estimate of ambient concentrations from

proposed project and future growth associated with project

• Purpose is to determine if new plus existing emissions will cause or contribute to a violation of a• NAAQS and/or • PSD increment

Air Quality Impact Analysis (AQIA)

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• A new source or modification cannot cause or contribute to significant deterioration of air quality in attainment areas• Maximum amount of deterioration allowed is called an

increment• Increments exist for• 3 pollutants (PM, PM10 and PM2.5; SO2 and NO2)• Various averaging periods (annual, 1-hour)• 3 area classifications (Class I, Class II, Class III)

AQIA for Increment Compliance

PM2.5 Increments by Area Classification (g/m3) NAAQS (g/m3) Averaging Period Class I Class II Class III

Annual 1 4 8 1524-hr 2 9 18 35

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• Change in air quality measured against a certain baseline• Not all sources consume increment• Two important concepts• Baseline area• All portions of attainment area in which PSD applicant proposes to locate

and/or would have significant ambient impact (i.e. higher than Significant Impact Level)

• Limited to intrastate areas: baseline areas not triggered across state lines

• Baseline date• When increment consumption starts, pollutant specific

AQIA for Increment Compliance (cont.)

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• Baseline Date(s) - when increment consumption starts, pollutant specific

AQIA for Increment Compliance (cont.)

Major Source Baseline Date

Minor Source Baseline Date

SO2 and PM - Jan. 6, 1975 NO2 - Feb. 8, 1988

Date of first complete permit application for a major source

or major modification

when actual emission changes from all sources affect the available increment

when actual emissions associated with construction at a major source affect increment

Start

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• A new source or modification cannot cause or contribute to a violation of any NAAQS in any area• Compliance with any NAAQS is based on proposed

source and all other sources in baseline area• No baseline dates exist• Analysis requirements similar to increment analysis

• NAAQS analysis is independent from increment analysis

AQIA for NAAQS Compliance

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• Compliance determined by using air quality models• Preliminary analysis (significant impact analysis)• Screening approach• Representative meteorology• Only proposed source or modification emissions • Refined receptor grids

• Full impact analysis (cumulative impact analysis)• Refined model• Representative meteorology• All applicable increment affecting sources• More refined receptor grids (smaller grid spacing)

AQIA Steps

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• Evaluation of NAAQS, Class I increments and Air Quality Related Values (AQRVs) when a major source’s emissions may affect a Class I area• Class I Area – areas reserved for special air quality protection, usually national

parks and wilderness areas• Class I Areas have stringent increments

• AQRVs – feature or property of a Class I Area that may be affected by a change in air quality (such as scenic, cultural, physical, biological, ecological, or recreational resources

• Generally for sources within 100 km of Class I area, not always• Federal Land Manager (FLM) must be notified of potential impacts on

Federal Class I Areas • Determines data and analyses needed

• http://www.epa.gov/visibility/class1.html

Class I Area Impact Analysis

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Map of Class I Areas

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• Role of FLM: evaluates a source’s projected impact on AQRVs, makes recommendations to permitting agency• FLM may recommend that permit application be denied if FLM

determines a source will adversely impact AQRV’s, even where applicable increments are not exceeded

• FLM may suggest permit conditions• FLM definition of adverse impact: an impact that• Diminishes area’s national significance• Impairs structure or functioning of ecosystems, or• Impairs quality of visitor experience

Class I Area Impact Analysis (cont.)

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AQRV Potential Air Pollution-Caused Changes

Flora and fauna Growth, mortality, reproduction, diversity, visible injury, succession, productivity, abundance

Water Total alkalinity, metals concentration, pH, anion and cation concentration, dissolved oxygen

Visibility Contrast, visual range, colorationCultural-archeological and paleontological

Decomposition rate

Odor Odor

Examples of AQRV’s for Class I Area Impact Analysis and Potential Air Pollution-Caused Changes

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• State or Indian governing body is responsible• Can define AQRV’s at own discretion• Establishes criteria for determining an adverse

impact on AQRV’s• EPA may be asked to resolve permit disputes

Managing Air Quality and Protecting AQRV’s in non-federal Class I areas

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• Assesses potential effects of increased air, ground and water pollution from proposed source and associated growth on:• Soils and vegetation• Visibility• Pollutant-specific• Performed within impact area of proposed

source

Additional Impact Analysis

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• Criteria for evaluating completeness and adequacy of applicant’s analyses• Whether applicant has presented a clear and

accurate portrait of soils, vegetation, and visibility in proposed impacted area• Whether applicant has provided adequate

documentation of potential emissions impacts on soils, vegetation, and visibility• Whether data and conclusions are presented in a

logical manner understandable by the affected community and interested public

Additional Impacts Analysis (cont.)

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• CAA section 165(a)(2) provides that a PSD permit cannot be issued unless there is an opportunity for a public hearing at which the public can appear and provide comment on the proposed source, including “alternatives thereto” and “other appropriate considerations.” • CAA allows EPA to consider environmental justice

issues in issuing PSD permits

Public Involvement

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• If your tribe has satisfied requirements for TAS for purposes of CAA sections 126(a) and (b), your tribe is entitled to 60-days notice prior to PSD source’s construction, and your tribe may petition EPA Administrator for a finding that the transported emissions from a proposed PSD source would contribute to nonattainment or interfere with maintenance of NAAQS in area covered by your TIP• Technical Support Document (TSD), generally including

responses to comments, may also be available with final permit

Public Involvement (cont.)

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• To obtain a PSD permit, an applicant must• Apply best available air control technology (BACT)• Conduct an ambient air quality analysis to demonstrate

that its new emissions would not cause or contribute to a violation of the NAAQS and/or PSD increment• Analyze whether its proposed emissions increases

would impair visibility or adversely affect soils or vegetation • Not adversely impact a Class I Area

• Public and tribes may comment on impacts of the proposed project, including environmental justice aspects

Summary