4 The record articles

Fine Particulate – What We Learned in 2009

Posted: January 19th, 2012

Author: All4 Staff 


Since U.S. EPA promulgated final rules governing the implementation of the New Source Review (NSR) program for PM2.5, ALL4’s PM2.5 Team has been tracking the NSR rule developments in order to be in a position to communicate and address the challenges that the rule has presented to our clients.  It became clear in the early stages of rule development that while the NSR program is a long-standing program with a full history, PM2.5 presents a number of unique challenges that we are not accustomed to dealing with for “traditional” NSR pollutants such as NOX and SO2.  These challenges cover a full spectrum of technical and policy issues including PM2.5 emissions quantification, emissions measurement, nonattainment area permitting requirements, and precursor provisions.  To keep you in tune with the challenges presented by PM2.5 requirements, ALL4 kept busy publishing the following articles  in 2009:

  • A Practical Guide to PM2.5 (March 2009): A guide to planning in advance for projects to address the PM2.5 NSR rules.
  • Filterable and Condensable Emissions Testing (March 2009): An article by Weston Solutions, Inc. summarizing the accepted PM emissions measurement techniques at the time and the limitations and advantages associated with those techniques.
  • PM2.5 Nonattainment – What You Need to Know (April 2009): A detailed technical summary of the challenges associated with PM2.5 permitting in nonattainment areas.
  • PM2.5 Prevention of Significant Deterioration (i.e., Attainment) – What You Need to Know (June 2009): A detailed technical summary of the permitting challenges related to PM2.5 that will be encountered in PM2.5 attainment areas.
  • PM2.5 NSR Regulation Update (August 2009): An update on the aspects of the PM2.5 NSR rules being reconsidered U.S. EPA.
  • PM10 Surrogate Policy Update (September 2009): An update on the most recent U.S. EPA guidance related to the use of PM10 as a surrogate for PM2.5 in construction permit applications.

ALL4’s PM2.5 Team has prepared this final 2009 PM2.5 Wrap-Up article to summarize what we have learned this year and to provide perspective on the challenges that we will continue to face moving forward.

2009 Wrap-Up/2010 Preview

The following items summarize the PM2.5 lessons learned, continuing challenges, and issues to be aware of as the calendar turns to 2010:

  • PM2.5 emissions data is still not widely available, but we now have effective and consistent promulgated test methods to measure PM2.5….kind of:  As described in ALL4’s “Practical Guide,” published emission factors for PM2.5 are not widely available, particularly for the condensable portion of PM2.5.  Therefore, you will likely see a need to perform emissions testing to support construction permit applications and to establish PM2.5 emission limits.  There is currently no promulgated test method to measure filterable PM2.5.  In addition, promulgated test method 202 (PTM202) to measure condensable PM2.5 is widely viewed as unreliable, subject to wide and inexplicable swings in condensable PM emission rates from run to run and a high bias as a result of nitrate and sulfate formation in the impinger water.  In response to these PM2.5 testing issues, U.S. EPA proposed to promulgate the following test methods in March 2009:
    • A cyclone method (currently designated other test method 27 (OTM27)) to measure the filterable portion of PM2.5.  This proposed filterable PM2.5 test method is not appropriate for high moisture exhaust streams or stacks with a diameter of less than one (1) foot.
    • A dry impinger method (currently designated OTM28) to measure condensable PM2.5 emissions that is intended to eliminate the high bias associated with PTM202. Look for these test methods to be introduced as the official promulgated test methods in 2010.  Although they represent a refinement over the currently promulgated test methods, they are not without limitations and are also more complex and more costly than their predecessors.  Plan ahead when considering a PM2.5 emissions testing program, and make sure that you utilize a reputable stack testing company with experience in performing these specific test methods.
  • The condensable PM2.5 grace period will end before 2011, after all:  When U.S. EPA promulgated the PM2.5 NSR regulations in May 2008, they established a grace period during which condensable PM2.5 did not need to be addressed in construction permit applications until January 2011, at which point adequate test methods would exist to measure condensable PM2.5.  Despite the establishment of this grace period, many states still requested that applicants address condensable PM2.5 before this date.  For those states that did not request condensable PM2.5 information, it appears that the grace period will end before January 2011.  As part of the emissions testing proposal described in the item above, U.S. EPA is also soliciting comments on ending the grace period early since methods that U.S. EPA considers adequate are available.  ALL4 anticipates that the grace period will end in 2010 and that all applications will require an evaluation of condensable PM2.5, which will likely result in more widespread use of the new dry impinger test method.
  • The days of the PM10 surrogate policy are numbered and case law may have new importance: After May 2008, there were still many states that used the PM10 surrogate policy in PM2.5 attainment areas to allow time for the development of state-specific PM2.5 NSR regulations.  Under this policy, applicants could address PM10 emissions increases and NSR requirements and avoid addressing PM2.5 directly.  Using PM10 as a surrogate for PM2.5 without qualifications had long been accepted practice consistent with 1997 U.S. EPA guidance on the issue.  Then, in August 2008, U.S. EPA issued an order in response to petitions of a construction permit application submitted in Kentucky.  In the order, U.S. EPA stated that PM10 could not be used as a surrogate for PM2.5 unless an adequate justification, that it was appropriate to do so, was provided for the proposed project.  When U.S. EPA provided very little in the way of clear guidance on how to prepare the requested justification, it was apparent that the PM10 surrogate policy will be difficult to use in the future and that PM2.5 will need to be addressed directly in all construction permit applications, regardless of location.  The U.S. EPA order also sent a concerning message that determinations made under the banner of case law can be used to dictate U.S. EPA decision making in lieu of the regulations that govern the Clean Air Act (CAA).  It remains to be seen if case law decisions will be used in a similar fashion in the future.
  • Construction permitting in PM2.5 nonattainment areas will continue to be extremely difficult:  NSR significant emissions increases in PM2.5 nonattainment areas must be offset by either direct PM2.5 emission offsets (also referred to as emission reduction credits (ERCs)) at a 1:1 ratio or precursor pollutant (SO2 or NOX) ERCs at a 40:1 or 200:1 ratio, respectively.  Satisfying the emission offset requirement has proven difficult for two (2) reasons:
    • Availability of ERCs:  Direct PM2.5 ERCs are very difficult to find.  In a state like Pennsylvania that maintains a formal ERC registry, the quantity of direct PM2.5 ERCs has at times, over the last year, numbered less than 100 tons of available ERCs state-wide.  Locating sufficient precursor ERCs can also be difficult due to the high offset ratios pertaining to precursor pollutants.
    • Justifying the use of ERCs:  ERCs must be purchased within the nonattainment area of use.  Unlike other NSR pollutants, PM2.5 nonattainment areas are geographically limited, sometimes to a single county.  Therefore, the initial search for ERCs may also be limited to a single county.  To purchase ERCs from another nonattainment area, applicants are required to demonstrate “ambient equivalence,” which means to demonstrate through air quality modeling that the purchased ERCs have an appreciable impact in the area of use.  This type of evaluation complicates the permitting process and will make it difficult to justify the use of ERCs that are located at a distance greater than immediately adjacent counties or nonattainment areas.

The combination of the lack of available of emission offsets and the requirement to justify their use from nearby nonattainment areas will likely halt certain projects before they can commence.  The purchase of ERCs should be among the first issues evaluated when critical path issues are being identified for a proposed project.

  • Standards will continue to be tightened:  The PM2.5 National Ambient Air Quality Standards (NAAQS) are currently 35 micrograms per cubic meter (ug/m3) on a 24-hour average and 15 ug/m3 on an annual average.  In 2006, the 24-hour NAAQS was decreased from 65 ug/m3 to its current level and the annual standard was retained at its current level.  Since then, the annual standard has been remanded back to U.S. EPA for further evaluation, specifically so that U.S. EPA can explain the basis for not tightening the annual standard.  ALL4 anticipates that the annual standard will be reduced, resulting in additional PM2.5 nonattainment areas.  A reduced annual standard will also make it more difficult to demonstrate NAAQS compliance in attainment areas, since the current background concentrations will already be at or near the NAAQS and will leave little room for concentrations predicted by air quality modeling.  ALL4 will continue to follow changes to the NAAQS as they develop.
  • Determining your PM2.5 attainment status is not as easy as it seems:  In response to the tightening of the 24-hour NAAQS described above, U.S. EPA published final nonattainment area designations in October 2008.  While these designations reflect the current 24-hour NAAQS, they did not change any of the nonattainment designations associated with the original annual NAAQS.  This has led to some confusion, since the nonattainment area boundaries changed in select cases from the original annual nonattainment areas to the current 24-hour nonattainment areas.  York County, PA is included in the same nonattainment area as the Harrisburg metropolitan area with respect to the new 24-hour NAAQS, but it remains a single county nonattainment area with respect to the 1997 annual NAAQS.  These inconsistencies will make evaluating PM2.5 requirements more difficult, and will sometimes force our clients to use the most conservative assessment (for example, a project in York County may trigger an ambient equivalency demonstration for any ERCs purchased outside of the county despite the new multi-county 24-hour nonattainment area).  At the very least, confirm your nonattainment status with the agency prior to commencing permitting, and understand where inconsistencies exist between the annual and 24-hour NAAQS.
  • Legality will continue to be questioned:  U.S. EPA was petitioned on and is reconsidering several aspects of the PM2.5 NSR rules, most notably the grandfathering of PSD applications and the PM2.5 precursor provisions.  These petitions are explained in detail in the August 2008 4 The Record  and represent examples of what will likely be continued legal challenges to critical aspects of the PM2.5 NSR rules that will impact the construction permit applications that we submit.

Although these items only touch on the highlights of the PM2.5 developments in 2009, we hope that they provide you with some perspective as you plan for 2010.  Refer to ALL4’s previous articles for detailed descriptions of the PM2.5 permitting requirements, and continue to keep PM2.5 requirements in the forefront of the air quality planning process for proposed projects.  Moving into 2010, ALL4 will continue to track the latest PM2.5 developments, and will continue to address PM2.5 in the context of our day-to-day air quality services.


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