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Related Practices
Related Practices

EPA Issues New Source Review Rule For Fine Particulate Matter

Beveridge & Diamond, P.C., May 27, 2008

On May 8, 2008, the Environmental Protection Agency (EPA) issued the second of three final rules for the implementation of fine particulate matter (PM2.5) limits under the New Source Review (NSR) program.  The rule was published in the Federal Register on May 16, and is available at 73 Fed. Reg. 28,321.

This rule is a continuation of a decade-long effort by EPA to incorporate PM2.5 limits into major source permitting.  Beginning in 1997, EPA established the first national ambient air quality standards for PM2.5.  Following the collection of ambient air monitoring data, EPA designated “attainment” and “nonattainment” areas for the PM2.5 standards, effective in April, 2005.  Under the Clean Air Act, states must submit state implementation plans (SIPs) to EPA within three years of a nonattainment designation, meaning that the first SIP amendments addressing PM2.5 nonattainment were due to EPA in April of 2008.

The newly issued rule addresses a number of PM2.5 NSR program requirements.  The most significant developments are the following:

  • EPA has exempted condensable PM emissions from coverage under the rule through 2011:  Particulate emissions consist of both a filterable fraction and a condensable fraction. The condensable fraction exists as a gas in an exhaust stream and condenses to form particulate once the gas enters the ambient air.  Id. at 28,344.  EPA believes that current test methods do not reliably measure the condensable fraction and that further study is necessary to develop an appropriate test method.  Therefore, EPA has created a transition period during which states do not need to address condensable PM in NSR permitting.  Id.  During this transition period, which is intended to extend no later than January 1, 2011, EPA is planning to conduct an assessment that will lead to the adoption of new or modified test methods in a separate rulemaking.  Id.  Most likely, this will take the form of a modification to the current EPA Method 22.  For any NSR permitting decisions made during the transition period, EPA will not revisit applicability determinations insofar as condensable PM is concerned.  Id. at 28,345.  EPA will interpret PM emissions limits in existing permits or permits issued during the transition as not requiring quantification of condensable PM2.5Id.
  • EPA has chosen to regulate some PM2.5 precursors but also not to regulate others:  EPA is not only regulating direct emissions of PM2.5, but is also regulating some of the pollutants that contribute to the formation of PM2.5, known as precursors.  Due to the uncertainty about the contribution of certain pollutants to PM2.5, EPA is regulating the precursors as follows:
    • Sulfur Dioxide (SO2):  Regulated.  Id. at 28,327.
    • Nitrogen Oxides (NOx):  Regulated unless a state demonstrates that NOx emissions do not contribute significantly to PM2.5 in that state.  Id. at 28,328.
    • Volatile Organic Compounds (VOC):  Not regulated unless a state demonstrates that VOC emissions contribute significantly to PM2.5 in that state.  Id. at 28,328-29.
    • Ammonia:  Not regulated unless a state demonstrates that Ammonia emissions contribute significantly to PM2.5 in that state.  Id. at 28,330-31.
  • EPA has established New Source Review thresholds for PM2.5The new rule defines a major source of PM2.5 as one that emits 250 tons per year (tpy) of both PM2.5 and its regulated precursors (or 100 tpy for certain listed sources). For existing major sources, the new rule defines significant emission rates for purposes of modification analyses at 10 tpy PM2.5, 40 tpy SO2, 40 tpy NOx, and 40 tpy VOC (if regulated).  Id. at 28,331-34. 

The most controversial portion of the rule is EPA’s decision to allow emission sources to avoid addressing condensable PM2.5 in direct emissions calculation for what is likely to be a three year transition period. This will effectively continue in force EPA’s now long standing policy of using PM10  limits as a surrogate for meeting PM2.5 limits.  See Interim Implementation for the New Source Review Requirements for PM2.5. (John Seitz, EPA, October 23, 1997); Implementation of New Source Review Requirements in PM2.5 Nonattainment Areas (Stephen Page, EPA, April 5, 2005).  EPA is also continuing to allow any state with federally approved PSD programs to use PM10 as a surrogate for PM2.5 during the period in which the state is revising its program to incorporate PM2.5 regulations.  73 Fed. Reg. 28,321, 28,340. Environmental organizations are reportedly considering a legal challenge to the rule to prevent a further delay in the mandatory use of direct PM2.5 analysis.

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For further information on this rule development, please contact Stephen Richmond at or (781) 416-5710, or Bethany French at or (202) 789-6042.