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Coarse PM: A Vital Policy Issue For The West. Presented by. Greg Schaefer Arch Coal Company. Coarse PM Has Been Excluded from PM NAAQS Regulation. The “fugitive dust exemption,” the “rural fugitive dust policy,” the exclusion of fugitive dust from “attainment” determinations,”
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Coarse PM: A Vital Policy Issue For The West Presented by Greg Schaefer Arch Coal Company
Coarse PM Has Been Excluded from PM NAAQS Regulation • The “fugitive dust exemption,” • the “rural fugitive dust policy,” • the exclusion of fugitive dust from “attainment” determinations,” • The lack of emission factors and models, Have All Resulted in Exempting Coarse PM from PM NAAQS Regulation Historically
How Strong Is the ScientificEvidence for Health Effects At Ambient Concentrations of Coarse PM? • “Weak” • “Limited” • “Very” or “Exceptionally Uncertain” • Most Studies Show No Effects or Marginal Effects At Levels Orders of Magnitude Above Those Proposed by EPA
DR. MCCLELLAN: “[T]he CD (EPA’s Criteria Document for PM) tries to selectively relate science to apparently meet some preconceived notations [sic: notions]. In this case, the apparent attempt is to provide the basis for a PM10-2.5 standard based on alleged associations with mortality and morbidity. In this case, the science does not exist.” CASAC letter to EPA Administrator Leavitt, August 16, 2004 at B-28 to B-29. (Emphasis added.)
DR. KOUTRAKIS: “The chapter [9 of the EPA Criteria Document] tried to make a case for a coarse . . . standard, and the case was not there. . . . FORMER CHAIR, DR. HOPKE: “Okay, but that comes across, and that’s a fair representation of the current state of the science . . . it’s going to be very difficult to build the case on the science alone for any particular coarse particle standard, . . .” Transcript of July 21, 2004 CASAC and PM Review Panel Meeting at 45-46. (Emphasis added.)
2. DR. KOUTRAKIS: “I just am not satisfied that the information put forward here is really supportive of [a coarse particle standard].” FORMER CHAIR, DR. HOPKE: “But, I think it’s a fair reflection of the literature….Now its up to OAQPS then to decide, based on other considerations besides the science, as to the need for and the nature of the standard.” Id. (Emphasis added.)
Health Effects of Coarse PM “It is my opinion that proposing a coarse PM standard is premature at this time.” “[T]he coarse PM data do not include positive findings from cohort studies, and the toxicologic data are slim. Further, there is good evidence that PM of crustal origin, as a subset of particles included in the coarse fraction, are not particularly toxic, as opposed to some other components in the coarse fraction. In many settings, the coarse fraction is dominated by crustal PM.” Dr. Sverre Vedal, CASAC Member, Written critique of EPA Staff Paper presented at CASAC Nov. 2003 meeting.
DR. MCCLELLAN: “Most of the text [of the Draft Staff Paper] appropriately summarizes the weak and inconsistent evidence for an association between urban PM10-2.5 exposure and excess health outcomes. Unfortunately, the summary portions of the chapter overstates this evidence. The nature of the evidence is at best suggestive of a weak association, it certainly does not raise to a level that can be considered suggestive of causality.”
DR. MCCLELLAN: “I have concluded that in the absence of a scientific basis specifically for a PM10-2.5 indication, the choice of such an indicator would be arbitrary and capricious.”
What is the Basis for the current 150μg/m3 PM10 Standard? Combustion PM Measured as British Smoke.
“Based on these considerations, staff concludes that a 24-hour PM 10-2.5 standard set so as to provide roughly equivalent protection to that afforded by the current PM 10 standard could provide some margin of safety against the more serious, but also more uncertain, PM 10-2.5 related mortality effects.” • SP at 5-69.
Dr. Sverre Vedal, PM Review Panel Member and Former Member of CASAC: “This attempt at equivalency, then, seems to result in a discrimination against western U.S. cities, as did the PM10 standards.”
The Result of EPA Staff’s Proposal Will Be to Impose a Coarse PM Standard That is Far More Stringent in the Arid West Where Rural Crustal PM10 Dominates Than in the Urban Areas on Which EPA Finds Limited and Uncertain Evidence to Support a Coarse PM Standard.
[EPA] Staff notes that these studies [finding weak, limited and uncertain associations] were done in areas in which PM 2.5, rather than PM 10-2.5 is the predominant fraction of ambient PM, such that they are not representative of areas with relatively high levels of thoracic coarse particles.” (Emphasis added.)
CASAC and the PM Review Panel Expressed Broad Support for Exclusion of Rural, Crustal PM from Any Coarse PM Standard at Their Meeting on April 6-7, 2005.
Health Effects of Coarse PM “The evidence clearly is much less persuasive, much less robust than for fine particles. So the option is to have a standard and not a very stringent one. Having a standard means that we’ll get a database, perhaps adequate in the next round but there’s hardly a basis for it being a very restrictive standard. So you know, practical considerations and not strictly based on scientific merit.” Dr. Mort Lippman, CASAC Transcript at 374 (Nov. 2003).