PM-10: IMPLEMENTATION OF STANDARDS A

PM-10: IMPLEMENTATION OF STANDARDS A Summary of the APCA/EPA International Specialty Conference C. V. Mathai Arizona Public Service Company Phoenix, Arizona David H. Stonefield U.S. Environmental Protection Agency Research Triangle Park, North Carolina John G. Watson, Jr. Desert Research Institute Reno, Nevada

The objective of the PM-10 Conference was to facilitate the exchange of ideas among the representatives of federal, state and local air pollution control agencies, industry, environmental groups and the air pollution scientific community at large toward the common goal of preparing and implementing the PM-10 SIPs based on the best available technical information. This report summarizes the conference's technical program. The U.S. Environmental Protection Agency (EPA) in 1971 established the primary and secondary National Ambient Air Quality Standards (NAAQS) for particulate matter, based on the data assessment presented in the EPA's 1969 "criteria document." The 1977 Amendments to the Clean Air Act (the Act) require the EPA to review, and where appropriate, revise air quality criteria and ambient standards every five years to ensure that the standards are based on the best available scientific information. In 1978 the EPA initiated the process to review and revise the criteria document and the NAAQS for particulate matter. That review process culminated in the EPA's promulgation of the revision of the particulate matter standards during the summer of 1987. The revision includes: • Replacing the total suspended particulates (TSP) as the indicator for particulate matter for ambient standards with a new indicator that includes only those particles with an aerodynamic diameter less than or equal to a nominal 10 fim—the so called PM-10; • Replacing the 24-hour primary TSP standard with a 24hour primary PM-10 standard of 150 /ug/m3 with no more than one expected exceedance per year; Copyright 1988—APCA

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Replacing the annual primary TSP standard with a primary PM-10 standard of 50 /*g/m3, annual arithmetic mean; • Replacing the secondary 24-hour TSP standard with 24hour and annual secondary PM-10 standards that are identical to the primary standards. The EPA is implementing the PM-10 standards under Section 110 of the Act. Section 110 requires each state to submit a State Implementation Plan (SIP) to the EPA for approval within nine months from the date of the NAAQS revisions (i.e., by May 1,1988 for the PM-10 standards). The SIP is to provide for the attainment and maintenance of the NAAQS through emission limitations and other measures as may be necessary. By the summer of 1987, the EPA had provided considerable guidance to the states and local air pollution control agencies on how to implement the PM-10 standards. Even so, the state and local agencies were somewhat overwhelmed by the task before them in implementing the PM-10 standards because it posed unique and technically complex problems to be solved in the short amount of time allowed by the statutes. Recognizing the need for a timely exchange of technical information about the PM-10 issues, APCA initiated the organization of an International Specialty Conference in June 1987. The EPA foresaw the excellent opportunity the conference could provide in easing the burden on those developing the SIPs and agreed to be a sponsor of the conference with APCA. Thus, it became an APCA/EPA International Specialty Conference, "PM-10: Implementation of Standards." The existing SIPs for implementing the TSP standards relied heavily on emission inventories and emission sourceoriented dispersion models. Recognizing the limitations of dispersion models, the EPA has recently approved the use of receptor-oriented models to supplement dispersion models for developing emission control strategies and implementing JAPCA

the PM-10 standards. Because of the emergence of the receptor models as a primary tool for preparing PM-10 SIPs, APCA decided to hold the APCA/EPA PM-10 Conference back-to-back with another APCA Specialty Conference, "Receptor Models in Air Resource Management," which was already planned for February 1988. These two conferences were held during February 22-26, 1988, at the Cathedral Hill Hotel in San Francisco, California. Both conferences were jointly hosted by the West Coast, Golden West, and Pacific Northwest International Sections of APCA with a single General Conference Committee responsible for making all local arrangements. The objective of the PM-10 Conference was to facilitate the exchange of ideas among the representatives of federal, state and local air pollution control agencies, industry, environmental groups and the air pollution scientific community at large toward the common goal of preparing and implementing the PM-10 SIPs based on the best available technical information. The PM-10 Conference consisted of a keynote session, a panel discussion and twelve regular technical sessions. Three of these sessions were designated as "overlap sessions" with the Receptor Models Conference. The overlapping of sessions provided an excellent opportunity for the conference attendees to interact and exchange ideas. This first ever back-to-back arrangement of two APCA Specialty Conferences turned out to be a tremendous success from the perspective of the. technical program contents and the response from the scientific community at the conferences. This success would not have been possible without the close cooperation between the two Technical Program Committees. The papers included in the PM-10 conference may be grouped into five sections, based on their technical content: • Policy and regulatory issues; • Intercomparison of PM-10 samplers and ambient PM10 concentration assessments; • Point and area source emission assessments and PM-10 emission factors; • Source apportionment of ambient PM-10 samples: dispersion and receptor models applications; and, • Emission control strategies and State Implementation Plan developments. A brief summary of the complete technical program is given below in the order of these topics. Section I. Policy and Regulatory Issues

The first paper by Gerald Emison provided an overview of the decade-long standards review process and the scientific data upon which the PM-10 standards are based. The paper also identified three principles which constitute the foundation of the PM-10 standards implementation program. These principles deal with the statutory requirements associated with preparation and submission of SIPs to the EPA (e.g., the nine-month time limit), area groupings (Group I, II, and III) to accommodate resource and technical information limitations, and the interim "dual review" for TSP and PM10 standards concerning prevention of significant deterioration (PSD) and new source review (NSR) permitting processes. During the conference, Mr. Emison acknowledged that the EPA recognizes the difficulties faced by state and local agencies in preparing SIPs within the nine-month period. He declined to speculate on what would happen if the deadline is not met; however, he added that EPA stands ready to assist the state and local agencies in whatever way possible. The second paper by David Stonefield discussed EPA's existing rural fugitive dust area (RFDA) policy and the proposed "three alternatives" to that policy. The paper reviewed comments received from the public on the EPA's July 1988

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RFDA proposal. He noted that the various commentators supported a continuation of the existing policy for PM-10 as well as the three alternatives EPA proposed. Mr. Stonefield added that EPA has formed an Interagency Work Group to study the public comments and that a final policy decision on RFDAs is anticipated by the end of 1988. Dan deRoeck's paper detailed the changes in the NSR process EPA promulgated in July 1987. The author noted that: a) the PSD program is the primary NSR mechanism, b) the EPA is engaged in developing PM-10 increments, and c) new and "modified sources" will be regulated under both TSP and PM-10 during the "interim" period. The author also acknowledged that the flexibility afforded to states in their new NSR programs for particulate matter would potentially lead to key differences in the requirements of various states, primarily in the case of non-PSD sources. Prospective source owners were advised to consult with appropriate permitting authorities to verify their requirements. The last EPA paper on policy and regulatory issues discussed the applicability of EPA's emission trading policy to PM-10 emissions. Barry Korb and Ivan Tether pointed out that new opportunities exist in the use of emission trading policy during the development of SIP requirements. However, they added that to implement the emission trading policy for PM-10, several adjustments and policy decisions must be made. For example, as there are no designated "attainment/ nonattainment" areas for PM-10, the EPA must decide how to implement the emission trading policy in areas that are exceeding the PM-10 standards. Nils Larson et al. presented an industry's perspectives of the PM-10 regulations. Although they applauded the EPA for replacing TSP with PM-10, they suggested that the implementation of the new standards should be delayed until reliable PM-10 data are available so that inadvertent emission controls are not mandated. They also criticized the EPA for not implementing PM-10 regulations for NSR and PSD permitting processes immediately, thereby requiring industries planning to construct new sources to undergo a dual TSP and PM-10 review and permitting process. The authors argued that the EPA already has the legal authority to replace TSP increments with PM-10 increments for NSR and PSD permitting, contrary to EPA's expressed opinion. The paper by James Lodge suggested that the PM-10 standards are based on questionable scientific data and that the standards are too stringent. Robert Ireson discussed the relationship between development of new policies and the improvements in modeling and analytical capabilities. Mr. Ireson's premise was that as policies are developed, they push the advancement of modeling and analytical techniques which in turn, open opportunities for new policies to be developed. The last paper in this section by Julian Chazin described data collected by Wisconsin to substantiate the claim that public complaints about soiling and nuisance from fugitive dust sources were caused mainly by particles larger than 10 /an. He argued that the secondary TSP standard (welfarebased) should have been retained by the EPA. He also suggested that the EPA's rationale for not retaining the secondary TSP standard was based on flawed assumptions. Mr. Chazin pointed out that states like Wisconsin will be forced to adopt their own secondary standards, potentially leading to nonuniform standards from one state to another. Summary of Keynote Addresses

Mr. J. Craig Potter, EPA's Assistant Administrator for Air and Radiation, in his keynote address, gave a general overview of the history of and the reasons for revising the NAAQS for particulate matter. He identified some of the problems with implementing the standards and the importance of the conference to the standards implementation process. Finally, he called upon the conference participants 889

to work together for the success of the PM-10 regulatory program and for improving the particulate matter air quality in the country. Mr. John O'Connor, Deputy Director of EPA's Office of Air Quality Planning and Standards, gave the second keynote address and had the unique opportunity to provide the closing remarks for the PM-10 Conference and the opening remarks for the Receptor Models Conference. He acknowledged the complexity of developing*PM-10 SIPs and emphasized the need for a cooperative effort by all parties. He stated, "we must maintain and nurture the partnership among the federal, state and local officials, control technologists, source operators, and environmentalists." Mr. O'Connor identified three key areas where cooperation was needed: policy development, source apportionment, and control strategy development. Reviewing the history and present status of receptor modeling, he noted the important role of receptor models in the PM-10 SIP development process. Summary of the Panel Discussion, "PM-10 Standards and Their Implementation"

Panel members were chosen to represent federal and state regulatory agencies, the air pollution research community, an industry, and an environmentalist group. Mr. John O'Connor acted as the moderator for the panel discussion. Opening remarks made by each panelist are summarized below. Mr. David Howekamp's (U.S. EPA Region IX) remarks were concerned with three issues: the long-term PM-10 nonattainment problem, the necessity for aggressive control programs, and the need for evaluating and controlling condensable and secondary aerosols. Mr. Howekamp stated that several areas in California and Arizona (e.g., Los Angeles and Phoenix) within EPA Region IX are unlikely to attain PM-10 standards within the maximum five year period allowed for attainment under the Clean Air Act, even if these areas implement all reasonably available controls. He suggested that new guidance from the EPA and Congress, similar to the proposed "Post-87 Ozone and CO Policy," is needed for PM-10. With respect to control programs, Mr. Howekamp noted that fugitive emissions, woodsmoke, and secondary aerosols are the largest contributors to PM-10 standard exceedances in many areas. He also stated that in California, primary emissions from smoke stacks have been reduced to the extent that they are insignificant when compared with the emissions from other sources. However, he pointed out that fugitive emissions from sources such as material handling facilities are to be further controlled. Mr. Howekamp added that secondary and condensable aerosols such as sulfates, nitrates, and organic compounds must be investigated and controlled, especially in areas such as Los Angeles. He also suggested that efforts should be made to improve the ability to predict secondary aerosol formation and to measure condensible particulate matter from stack emissions. Mr. Terry McGuire of the California Air Resources Board, representing a state agency, discussed the problems caused by a lack of PM-10 data and the complexity of the pollutant. He noted that it may be more difficult to attain the PM-10 standards than the ozone standard. The difficulties include problems in monitoring such as loss of nitrogen oxides compounds from filters, formation of secondary aerosols, the control of fugitive dust, and the control of wood burning. Mr. McGuire stated that control agencies must shift emphasis from controlling industries to controlling individuals. He concluded that, in many cases, the only realistic solution will require Clean Air Act amendments. Dr. John Watson of the Desert Research Institute, representing the research community, discussed what it meant to have an expected form of the standard and the new tools, 890

including receptor modeling, that are available for developing and evaluating SIPs. He recommended that agencies need to look at the effect of emissions control with respect to "dollars per /ttg/m3 reduction" rather than with respect to "dollars per ton of emissions reduction." Dr. Watson expressed the opinion that chemical speciation and source apportionment technology is now developed enough to make this feasible. Mr. Richard Kerch of Consolidation Coal Company expressed some disappointment about the final standards which were promulgated and certain concerns about implementing them. First, he noted that the industry had preferred a 6 /urn cut point rather than the 10 /im chosen. He also stated that the chosen standards cannot be justified by health effects data and that the standards are too stringent. He was particularly concerned about the treatment of fugitive dust and its impact on the mining industry. He criticized the EPA for not adopting PM-10 increments for PSD purposes and the requirement for industry to go through a dual TSP and PM-10 permitting process. Mr. Kerch expressed the opinion that the EPA already has the authority to adopt PM-10 increments for PSD purposes. Mr. Robert Yuhnke of the Environmental Defense Fund suggested that the PM-10 standards were not adequate to protect public health. He pointed out that nationally, sulfates account for up to 20-25 percent of the PM-10 and that health effects of sulfates were not adequately considered. He stated that the regulatory agencies should control carcinogenic emissions from such sources as diesel vehicles. He also expressed concern about woodsmoke which contributes significantly to PM-10 in many areas such as Denver. Mr Yuhnke recommended that EPA should establish particulate matter emission standards for both gasoline and diesel powered vehicles at the earliest possible time. Section II. Intercomparlson of PM-10 Samplers and Ambient PM-10 Concentration Assessments

In the first paper, Larry Purdue reviewed EPA's Federal Reference Method (FRM) to measure ambient PM-10 concentrations. The FRM is based on discrimination and selection of PM-10 particles by inertial separation followed by conventional filtration and gravimetric analysis of filter samples. To date, EPA has approved the Wedding & Associates Inc. Critical Flow and several models of Andersen Samplers Inc. high-volume PM-10 samplers as "reference samplers." Mr. Purdue also noted that under the PM-10 regulations, continuous PM-10 monitors could qualify as "equivalent methods," and that EPA is encouraging manufacturers to perform the necessary testing and to seek EPA approval as equivalent samplers. The six papers by Mathai et al., Wedding et al., Lucas et al., Hoffman et al., Walter John, and Hayes et al., all described intercomparisons of PM-10 concentrations determined using commercially available high-volume PM-10 samplers manufactured by Wedding & Associates Inc. and a series of models by Andersen Samplers Inc. (commonly known as Sierra-Andersen Models 321,321-A, 321-B, 321-C, 321-G, 321-AG, and 1200). Considerable controversy existed in the scientific community on the question of the "accuracy" and reliability of PM-10 concentrations obtained using these samplers. The results of these studies suggested that the PM-10 values obtained from the Andersen samplers progressively became closer to the Wedding sampler after each modification of the former. However, even with the latest Andersen sampler version, there appeared to be about a 12-19 percent difference between the PM-10 values measured by samplers from these vendors, depending on field conditions. These researchers agreed that all the samplers require some form of regular maintenance and that future intercomparison studies should include measurement precision estimates using duplicate sampling. JAPCA

The papers by Barnes et al. and Dale Shimp discussed the use of a beta attenuation monitor (BAM) for measuring PM10 and a comparison of its performance with collocated highvolume PM-10 samplers. The BAM determines PM-10 concentrations based on the attenuation of beta rays passed through a tape upon which particles are collected for about an hour. This method enables collection of PM-10 data on an hourly-average basis. Collocated sampling with BAM and commercial PM-10 samplers showed good agreement. Although the BAM is much less labor intensive than conventional PM-10 samplers, the authors noted that much additional testing remains to be completed before it can be designated as an equivalent sampler. The paper by Briggs and Spengler assessed recent trends in particulate matter concentrations measured in six U.S. cities in order to provide a historical perspective for the PM10 standards implementation process. They constructed an eight-year trend in PM-10 concentrations using regression analysis of TSP, PM-15, and PM-10 data. The analysis showed statistically significant decreasing trends in PM-10 values for three cities studied and small downward changes in others. Countess et al. discussed inequalities in the PM-10 concentrations as a result of biases introduced by measurement devices, sampling media (positive and negative filter artifacts), and sample analyses methods. The authors suggested establishment of uniform standard operating procedures, primary standards, periodic field and laboratory intercomparisons, and third party audits of sampler performance and laboratory analytical methods. The PM-10 regulations interpret the PM-10 standards in terms of a "decision rule" for determining the area's attainment/nonattainment of the standards. Allison Mason presented a statistical methodology, which takes into account variation in PM-10 measurements and the effect of autocorrelation, for testing a hypothesis on the area's probability of meeting the standards. The probability of the area's misclassification (Group I, II, or III) was also explored using statistical models. Grosser et al. presented an estimation procedure, which involved fitting a statistical distribution to the upper tail of the PM-10 concentration distribution, in order to estimate the 24-hour "design value." The results of a simulation study designed to measure the accuracy and variability of the method and illustration of its use on a set of data collected in Southern California were also discussed. In order to make statistically valid comparisons, the regulations require daily PM-10 measurements from some locations. As many sites monitor PM-10 concentrations less frequently, EPA guidelines specify procedures for estimating PM-10 values for days on which data are missing. The paper by Merlyn Hough proposed an alternate method to estimate similar "missing" values, using a regression relationship between available PM-10 and TSP data, and light scattering coefficient (as a surrogate for fine particle loadings). The study showed that both EPA and the alternate method provided identical results for annual average PM-10 values; however, the alternate method predicted values in better agreement with measurements than the EPA method for 24hour PM-10 values. Section III. Point and Area Source Emission Assessments and PM-10 Emission Factors

With the promulgation of the PM-10 standards, state and local air pollution control agencies are being required to develop PM-10 emission inventories within their jurisdictions for the ultimate purpose of designing emission control strategies. Traditionally, these agencies have used emission factor data published by EPA in "Compilation of Air Pollutant Emission Factors, AP-42" for developing emission inventories for various source categories. The paper by MartiJuly 1988

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nez et al. reviewed PM-10 emission factors already available in AP-42 for various types of point sources and area sources. The paper also identified information gaps and discussed studies currently underway to fill these gaps. Recommendations were also provided to address specific problem areas. Efforts have been under way over the past several years to develop methods to determine PM-10 emissions from point sources, primarily under EPA sponsorship. Tony Eggleston reported on an evaluation of the PM-10 particle collection characteristics of equipment traditionally used for stationary source sampling (such as in situ cascade impactors and cyclones) and ambient PM-10 samplers. The results of this analysis indicated that the average PM-10 fraction of the source's total mass emissions determined by the "classical" source testing method is 73 percent whereas, if an ambient sampler-type of equipment were used, this fraction would have been only 53 percent. The author concluded that this significant overestimation of the PM-10 fraction of source emissions would result in unnecessary emission control requirements. Farthing and Ward discussed two methods to measure PM-10 emissions from point sources—the emission gas recycle (EGR) and simulated Method 5 (SIM-5). The authors described the samplers used for inertial separation, sampling nozzle criteria to minimize measurement errors and a comparison of the precision and accuracy of the two techniques. They also discussed the need for a standardized "dilution sampler" for PM-10 emission measurements and described recent work to develop such a system. Dan Redline described a PM-10 dilution source sampler developed by NEA Inc. This sampler uses a commercially available dichotomous sampler (virtual impactor) for aerodynamic particle separation which allows sample collection on substrates suitable for various chemical composition analyses. Wendt and Garza presented the results of a regression analysis qf air quality and emissions data from various California air basins in order to estimate the contributions of automobile emissons on ambient PM-10 concentrations. This analysis attributed only 6 percent of the primary particulate matter emissions to mobile sources, although their total contributions to PM-10 (through secondary particle formation) has been determined to be between 29 and 38 percent. The regression analysis also suggested that even if all the primary emissions were reduced to zero, the average PM-10 concentrations in large areas of California would be above 24 ixg/mz, resulting primarily from particle reentrainment. Chatten Cowherd presented a refined calculation scheme to address particle emissions due to the wind erosion process from bulk storage piles. This calculation scheme incorporated the findings of recent wind tunnel studies performed in the field and laboratory. The results were provided for different particle size fractions including PM-10. The significant contributions of unpaved roads to ambient particulate matter have long been well recognized. Gary Stensland described a study to develop PM-10 emission factors for unpaved roads using both exposure profiling techniques and dispersion modeling. The results of this study showed that both methods provided similar PM-10 emission factors. The study also demonstrated that commercially available ambient PM-10 samplers can be successfully used to develop emission factors for area sources. Robert Bryan's paper reviewed particle size-specific emission factors for various operations involving processing and handling of solid bulk materials. These operations include bulk transfer, continuous transfer, crushing, grinding, screening and other size classification activities for such materials as metallic and non-metallic minerals, coal, coke, cement, grain and fertilizers. The paper described the parameters influencing emission rates and the test methods for quantifying PM-10 emissions. These methods were ranked 891

according to criteria of expected accuracy, interferences, ease of use and cost. The significant role of planned and wild forest fires in impairing visibility and fine particle loadings have long been established. Two papers by USDA Forest Service personnel discussed methods to estimate PM-10 emission factors from prescribed forest fires. In the first one, Peterson and Sandberg proposed a program containing four levels of effort and accuracy for developing a national PM-10 emission inventory from such fires. The second paper by Ward et al. presented emission factor data collected using airborne sampling, surface-based sampling using towers, and combustion hood systems. Emission factors were determined for three particulate matter size fractions—PM-2.5, PM-10 and TSP. The study showed that 40-95 percent of the TSP were in the PM-2.5-and-under size fraction, depending on the heat release rate during the burn. The last paper in this section by Huhn et al. described a particulate matter inventory generation and modeling system for Denver, Colorado. The system was designed around routinely published housing, employment, land use, and traffic data. Inventories were generated as grided area emissions indexed by source category, season, day/night, and grid coordinates. Section IV. Source Apportionment of Ambient PM-10 Samples: Dispersion And Receptor Model Applications

This section consisted of eleven papers from two of the "Overlap Sessions" of the two Specialty Conferences. In the first paper, Lurman et al., provided an overview of multivariate statistical models including receptor and dispersion models. They also discussed recent advances in gas-to-particle conversion studies and their potential impact on PM-10 concentrations. Gray et al. presented the results of an extensive analysis of coarse (2.5-10 ixm) and fine (