Review of the Air Quality Criteria Document for Particulate Matter

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these appendices. While the recent studies regarding the relationship of heart rate variability toPM exposure provides one possible biological mechanism for the cardiac effects that may causemorbidity and ultimately premature mortality, other potential mechanisms for cardiovasculareffects have also been identified (e.g. plasma viscosity, coagulation). The NMAPS data inAppendix 6B should be integrated into the body of Chapter 6, with the daily deaths expressed asan age adjusted rate as well as number of deaths.Pg. 6-138: The use of the term “recent” in reference to the 1997 study by Peters et. al. isinappropriate in a document that will be released in 2002. The use of this adjective with respectto studies in this entire chapter should be reviewed to ensure that only studies published in thelast year or so are referred to as “recent”, or alternatively the adjective should be eliminated fromthe chapter’s discussion of studies.Chapter 9: Integrated Synthesis: Particluate Matter Atmospheric Science, Air Quality,Human Exposure, Dosimetry, and Health Risks - General CommentsWhile this chapter is somewhat improved compared to the previous draft in terms ofwriting style and providing some integration of information from different scientific disciplines,the underlying flawed approach of providing sequential summaries of what has already beensummarized in previous chapters is retained. As such, this crucial chapter still does not providethe reader with a true integration of the key information identified in the previous chapters asbeing of major significance for the air quality standard-setting process.In my December 1999 comments on the previous draft of this chapter, I had suggested anapproach that would structure the information provided in this chapter as responses to severalkey questions regarding the health science information published since the previous CriteriaDocument. In his written comments on this current chapter, Dr. David Bates has also suggested asomewhat similar approach to structuring this chapter. As it currently is written, there is asignificant amount of repetition of information already provided and summarized in the previouschapters. Key new information regarding PM exposure, toxicology, clinical studies andepidemiology are not currently integrated in a manner that informs the standard-setting process.Specific CommentsPg. 9-65; lines 2-5: The data audit performed for the HEI Reanalysis Project was not conductedby the study investigators as currently indicated in the text. The data audit was performed by anindependent team selected by HEI to perform this function for the study.Warren White, PhD4.3 Effects on Visibility - First impressionsThe visibility portions of the March 2001 draft CD were prematurely circulated for externalreview. Their inferiority relative to other parts of the document underscores the Agency’s longstandingdisdain for this subject. I can think of no harsher criticism of the material than simplyreproducing a few of the highlights. Keep in mind that all come from fewer than two dozenpages!Some of the lines could have been written by Edward Lear:“Light absorption by aggravated carbon at visible wavelengths is enhanced by no more than 30%and diminishes if encapsulated by a nonabsorbing aerosol.” (P4-90, L 19)A - 81
“At the surface, a variable fraction of the solar radiation is reflected back upwards, referred to assurface reflectance or the albedo, illuminating the atmosphere from above and below.” (P 4-88,L 4)“The increase was largest in the summer and decreased in the winter.” (P 4-108, L 28)“Some of the visibility impairment in northern California and Nevada, including Oregon,southern Idaho and western Wyoming, ...” (P 4-109, L 16)“Horvath (1993) reported that measured light absorption efficiencies for light absorbing carbonranges from 3.8 to 17 m 2 /g. According to Horvath (1993), calculated absorption efficiencies aretoo high, ranging from 8 to 12 m 2 /g for monodispersed carbon particles.” (P 4-90, L 12)“For most rural eastern sites, sulfates accounts for >60% of the annual average light extinctionon the best days ..” (P4-108, L 23)“However, several sites are not showing steady improvements in either visibility or PM 2.5 ,particularly in the number of worst visibility days (90 th percentile).” (P 4-111, L 20) [In otherwords, the number of days in a year is holding steady at about 365 per.]There are tautologies and circular definitions of the sort associated with Lewis Carroll:“Human vision is one of the factors that affects the way an object is viewed.” (P 4-86, L 10)“Discoloration may be used as a quantitative measurement of atmospheric color changes inurban hazes.” (P 4-98, L 2) [In much the same way as morbidity can be used as an indicator ofimpaired health.]“The light-extinction coefficient is the quantitative measure of haziness, defined as σ ext =K/visual range, where K is the Koschmieder constant. The value of K is determined both by thethreshold sensitivity of the human eye and the initial contrast of the visible object against thehorizon sky. The visual range may be calculated from the light-extinction coefficient using theKoschmieder equation ..” (P 4-94, L 23)There is simple technical ignorance:“The cones, a receptor cell in the retina, govern visibility interpretations.” (P 4-86, L12) [Thisis why an eyeball can be offended by haze even after surgical removal from the head. And whywe see nothing after sundown.]“Some of the light in the sight path is absorbed or scattered towards the observer. The remaininglight is absorbed or scattered in other directions.” (P4-86, L 24) [Leaving the observersearching in vain for any transmitted image.]“The scattering and absorption efficiencies are determined by estimating the size distribution ofeach particle.” (P 4-89, L 20)“.. the extinction coefficient that is calculated from the visual range, corrected to 60% relativehumidity by the Koschmeider relationship.” (P 4-109, L 29) [Versatile guy, that K.]“Mie scattering is the scattering of all visible wavelengths equally (Shodor EducationFoundation, Inc., 1996).” (P 4-87, L 1) [Which must be why Mie theory is computationally sotrivial. Distressingly, this claim is supported by the citation, which turns out to be on-linetraining material developed for the Agency. The cited page also explains “how the shorterwavelengths which our eyes detect as blue when mixed, are scattered at a right angle. If the sunA - 82
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known, the potential causes deserve
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SCIENCE ADVISORY BOARD STAFFMr. A.
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Page 2-77, line 19-22: Should menti
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mode vs. the other. In fact, such k
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p. 7-49, l. 20 In an effort to make
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ambient PM effects. The paragraph d
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dominant, one criticism is that “
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6. Susceptible sub-populationsIt is
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is OK. But in most settings it stil
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2. There are repetitions of the sam
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15. Page 3-57 and 3-58, line 29-31
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P 7- 27, L 15: What does “compara
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there is pertains almost solely to
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studies, and is presented as observ
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P 8-47, L 23-27: These two sentence
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