Review of the Air Quality Criteria Document for Particulate Matter

Page 2-77, line 19-22: Should mention new developments in Synchotron XRF. It appears tohave much higher sensitivity that will permit much higher time resolution.Page 2-81, lines 5 and 6: The uncertainties in the reported slope and intercepts should bereported. There should always be uncertainty estimates with any reported data or data analyses.Page 2-82, line 6: There are a number of references to papers in the PM2000 issue of AerosolSci. Technol. This issue was published in January 2001 and thus, all of these references likeChow et al. need to be updated.Page 2-88, line 20: Same date problem. Also need to point out why we want better time resolveddata. We have been adjusting the time interval of the O 3 standard because we have the data toaggregated the data at various time intervals. We do not have that advantage with PM unless“continuous” monitors are more widely used.Page 2-94, lines 1-10: Fergenson et al. (In press, 2001) have shown that quantitative estimatescan be made of the aerosol composition from the single particle MS data.Page 2-96, lines 1-12: Need to add the Continuous Sulfate Monitors that are now available.There is no discussion of measurement methods for Coarse particles and how you would getsamples that could be used to characterize the particle compositions, do source apportionment,etc.Chapter 3.There needs to be a clearer focus on what is know about the concentrations, sources,distributions, compositions of coarse particles. There is too much emphasis on PM 10 and notenough on coarse. Chapters 4 and 6 single out the effects of coarse. This chapter needs tocoordinate with the background atmospheric behavior so that the context for the subsequentchapters has been created. There is only a short section on Page 3-11. If this is all theinformation that is available, then there has to be a clearer statement that information on PM 10-2.5is limited and that this is all there is that is known regarding its distribution nationwide.Page 3-19, Because of the very large variability in the relative amounts of fine and coarseparticles, it is misleading to provide only a mean PM 2.5 /PM 10 ratio. The only sensible way toprovide such information is with distributions.Page 3-26, lines 4 -10: Need to have the discussion of active homogeneous nucleation in Chapter2 and need a pointer back to that discussion here.Page 3-36, lines 10-21: A major part of secondary particles in the east and maybe elsewhere issecondary organic aerosol. Thus, there needs to be a discussion of the sources of the precursorgases that include both anthropogenic and biogenic sources.Page 3-37, lines 23-31: Should add a discussion of UNMIX. EPA has invested in getting thismodel ready for use and should be included in this discussion.Page 3-42, lines 11-28: This discussion is out of date. More recent data suggests a much moreimportant role for SOA in the eastern US ambient aerosol.Page 3-51, lines 8-11: Agriculture is a major source of ammonia. Take for example the Chinofeedlot. With dairy farming widespread in the NE and North Central US, it could be importantin the eastern US as well.A - 2