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New Source Review Fine Particulate Matter PM10 Surrogate Policy Update

Posted: January 19th, 2012

Author: All4 Staff 


PM2.5 became a regulated air pollutant in 1997 with the promulgation of the annual and 1-hour PM2.5 National Ambient Air Quality Standards (NAAQS).  As a regulated pollutant under the Clean Air Act (CAA), U.S. EPA must enforce New Source Review (NSR) permitting requirements for PM2.5 that apply to major modifications or major new sources.  These NSR requirements include programs that address areas that are in attainment with the NAAQS (referred to as the Prevention of Significant Deterioration or PSD program) and those areas that are not in attainment (referred to as the Nonattainment NSR or NNSR program).  Since NSR requirements that specifically addressed PM2.5 did not exist at the time the NAAQS was promulgated, U.S. EPA issued a guidance memorandum outlining how PM2.5 was to be addressed as part of construction permit applications on October 24, 1997.  The guidance document, herein referred to as the “Seitz memo,” specifically recommended that PM10 could be used as an appropriate surrogate for PM2.5 within the NSR permitting process.  In other words, quantifying PM10 emissions and addressing NSR requirements specifically for PM10 (air quality modeling, pollution control requirements, etc.) would be sufficient to satisfy any concerns that U.S. EPA may have related to PM2.5.  U.S. EPA recommended this approach citing the lack of the necessary tools to quantify PM2.5 emissions and the lack of available ambient PM2.5 monitoring data at the time.

In May 2008, U.S. EPA promulgated Federal NSR rules that specifically addressed PM2.5 emissions.  These Federal rules became effective immediately in PM2.5 nonattainment areas (NNSR).  However, the transition to the new rules in PM2.5 attainment areas (PSD) is dependent on the location of the project:

  • In states with regulations that directly reference the Federal PSD rules with no date reference and in PSD “delegated” states, the Federal PM2.5 PSD rules became effective immediately in May 2008.
  • In states that implement their own PSD program (i.e., SIP-approved states) and do not reference the Federal PSD rules, the Federal PM2.5 PSD rules did not take effect, and these states have until January 2011 to incorporate PM2.5 into their state PSD rules.  In the interim, U.S. EPA suggested that the PM10 surrogate policy outlined in the Seitz memo continue to be used.

Recent Surrogate Policy Developments

Despite U.S. EPA’s initial recommendations that the PM10 surrogate policy be used in areas that have additional time to implement the Federal PM2.5 rules, a recent U.S. EPA order in response to petitions raised against a Louisville Gas and Electric (LG&E) construction permit application includes contrary recommendations and requirements.  Petitioners to the application challenged whether the PSD construction permit application, which utilized PM10 as a surrogate for PM2.5 in accordance with the Seitz memo, had appropriately addressed PM2.5 emissions.  The objections to the permit specifically claimed that the use of the PM10 surrogate policy is not appropriate because LG&E did not sufficiently demonstrate that PM10 is a “reasonable” surrogate for PM2.5.  U.S. EPA agreed with the petitioners, asserting that the PM10 surrogate policy cannot automatically be used in PSD permit applications, but that the source needs to demonstrate that PM10 emissions are appropriate for addressing PM2.5  emissions.  In making this assertion, U.S. EPA drew comparisons to Maximum Achievable Control Technology (MACT) standards in which U.S.

EPA to justify the use of PM as a surrogate for Hazardous Air Pollutant (HAP) metals.  This is contrary to the original Sietz memo, which appeared to allow the universal use of the PM10 surrogate policy for addressing PM2.5 emissions.

Based on the latest U.S. EPA recommendations, any PSD construction permit application in which PM10 emissions are quantified and that addresses Best Available Control Technology (BACT) and air quality modeling requirements for PM10 exclusively (consistent with the Seitz memo) must also contain a demonstration for why PM10 is an appropriate surrogate for PM2.5.  U.S. EPA suggested two (2) possible approaches for making this demonstration:

  • Establish a strong statistical relationship between PM10 and PM2.5 emissions, both with and without any proposed emission control technologies.
  • Show that any PM10 BACT-selected control devices would be the same if a BACT evaluation would have been performed specifically for PM2.5.

Little additional guidance is provided on the details of the suggested approaches and whether they would address both the filterable and condensable fractions of PM10 and PM2.5.  Both approaches suggest that a full PSD evaluation of PM2.5 emissions, including quantifying emissions and establishing a BACT level of control, will be required as part of any PSD permitting evaluation regardless of the status of the appropriate state’s PM2.5 implementation process.  U.S. EPA has indicated that they will begin to apply this new interpretation of the PM10 surrogate policy immediately.

Air Permitting Recommendations

Obtaining source-specific PM2.5 emissions data is the best way to address PM2.5 emissions as part of any air permitting process that involves PM emissions and that could potentially trigger PSD permitting requirements.  Therefore, ALL4 recommends that regulated facilities consider taking the following steps to prepare for such a permitting event:

  1. Evaluate the emitting units that are contributors to the facilities’ PM emissions profile and determine if appropriate and representative PM2.5 emission factors are available from U.S. EPA, industry groups, or other reliable sources for those units.  Since permitting typically results in compliance testing requirements, relying on published emissions factors may be a dangerous tact when permitting facility changes.  Therefore, facilities should consider performing PM2.5 emissions testing on any units that would be expected to have testing requirements as part of a new construction permit.  This consideration would be applicable for both modified and affected emission units that would be included in an air quality construction permit evaluation.
  2. If the installation of new equipment is planned, approach equipment vendors as early as possible regarding the availability of PM2.5 emissions data and require that they provide guarantees regarding this pollutant in their proposals.  (Some may need to perform emissions testing if data is not already available).

In all cases, data on both the filterable portion of PM2.5 (measured by U.S. EPA Method 5) and the condensable portion of PM2.5 (measured by the U.S. EPA proposed dry impinger method) should be obtained since both portions are required to be evaluated for PSD applicability purposes.

Source-specific emissions data will alleviate a common problem with addressing PM2.5 emissions under PSD; namely, being forced to accept PM2.5 emission limits that are based on generic emission factors and that could result in compliance issues after completion of the project.

If the source-specific emissions data indicates that a project will be subject to PM2.5 PSD requirements, the approach that is used to satisfy those requirements should be carefully considered, particularly as it relates to including condensable PM2.5.  At this time, discussions with the permitting authority could include a proposal that any BACT demonstration focus on filterable PM2.5 only, since there is limited precedent for determining BACT for the control of condensable PM2.5 that exists in a vapor phase in a stack.  A more conservative approach can be used in the PSD air quality modeling evaluation, where total PM2.5 is modeled as a first cut and the emission rates are subsequently refined if more realistic emissions data is required to demonstrate compliance with the NAAQS.


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