Review of the NARSTO Draft Report NARSTO Assessment of the Atmospheric Science on Particulate Matter (2002) / Chapter Skim
Currently Skimming:
4 Comments on the Assessment's Chapters and Related Appendixes
4 Comments on the Assessment's Chapters and Related Appendixes
Pages 31-50
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From page 31... ...
Indeed, an infinite number of conceptual models could be developed for different regions, times, and conditions, such as those prepared for the nine regions discussed in Chapter 10 of the draft. Once the framework for informing airborne-PM management is clearly presented in Chapter 1, attention needs to be paid to doing a better job of linking to and being consistent with the rest of the document.
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From page 32... ...
The policy-relevant points should be summanzed and re-emphasized in a concluding policy implications section, as suggested for all technical chapters. Ending the chapter with a section on PM climate effects tends to be a diversion rather than providing a focusing summary.
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From page 33... ...
The direct climate effect is actually a balance between visible and near infrared scattering and absorption. Scattering, which leads to cooling, dominates for most aerosol particle types.
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From page 34... ...
The discussion of using receptor-based and source-based models to validate emission inventories in Chapter 3 appears inconsistent with the discussion of these tools in Chapters 6 and 7. Chapters 6 and 7 seem to indicate that the modeling tools can be used in a "weight-of-evidence" mode to help to evaluate the accuracy of inventories.
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From page 35... ...
First, the research-grade instruments and deployment strategies used to gain scientific understanding are often much more sophisticated, accurate, and reliable than the instruments and techniques used to monitor compliance; to develop emission inventories, exposure assessments, and source attributions; and to evaluate program success. Thus, some measurements are of much higher quality than others.
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From page 36... ...
CHAPTER 5: "SPATIAL AND TEMPORAL CHARACTERIZATION OF PARTICULATE MATTER CONCENTRATION AND COMPOSITION"; APPENDIX C: "MONITORING DATA: AVAILABILITY, LIMITATIONS, AND NETWORK ISSUES"; APPENDIX D: "GLOBAL AEROSOL TRANSPORT" Chapter 5 is generally well done, presenting a host of PMlo and PM2 s data from a wide variety of North American monitoring networks. Recent and historical data Tom a number of
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From page 37... ...
. ~ some useful discussion ot the analytic errors that attect data accuracy and the statistical sampling and measurement errors that affect data precision in Sections C.2 and C.3 of the supporting Appendix C
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From page 38... ...
Many factors contribute to the high levels of particle concentrations that have been observed in those areas, including the nature and characteristics of the emission sources, land use and topographic characteristics, and meteorologic conditions (Muker~ee 2001; Mejia-Velazquez and Rodriguez-Gallegos 1997~. Chapter 5 should discuss the areas.
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From page 39... ...
Each chapter should present the policy relevance of the material in a parallel manner in a final "Policy Inclinations" section, as recommended for all technical chapters. The policyrelevant material in Chapter 6 is now found in Section 6.5, which addresses how modeling tools are applied in PM policy development, and in Section 6.6, which includes answers to "science questions" that are similar to but not exactly the same as the PQs used in the executive summary.
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From page 40... ...
That ambient PM2.s was predicted to be largely unaffected by fuel sulfur reductions suggests that perhaps other sources might be better emission-reduc-tions targets. It seems that one could conclude from the modeling activities that targeting the large amount of nonvehicular ammonium sulfate or vehicular emissions of organic material and nitrate may be more effective for reducing PM2.s.
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From page 41... ...
A second problematic example is the discussion of"Haze in the Grand Canyon." The modeling activities indicated that emissions of SO2 from the Mohave Power Project did not contribute much to the sulfate observed over the Grand Canyon, but a decision to install sulfur scrubbers was made nonetheless. Again, the modeling results did not seem to guide the policy decision.
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From page 42... ...
Likewise, how CTMs are used to elucidate the aspects of the framework for airborne-PM management, particularly the conceptual model for airborne-PM burden and the management scenarios, should be described. The policy-relevant material in Chapter 7 is in Section 7.4, "What Questions Can Chemical Transport Models Address and How Well?
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From page 43... ...
The committee recommends that Chapter ~ undergo major revision to correct conceptual errors, improve readability, reduce reliance on technical terminology, and highlight opportunities for interaction between health and atmospheric scientists. Ideally, this chapter should provide atmospheric scientists with a hilly accessible summary of PM health effects that helps them to frame their work better.
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From page 44... ...
Likewise, a discussion of research avenues for atmospheric scientists to pursue to assist health scientists would be useful. For example, epidemiologic analyses indicate spatial heterogeneity in PM health effects, but the extent to which the spatial variability can be explained by PM composition or atmospheric chemistry is unknown.
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From page 45... ...
Some discussion of the recently proposed regional haze rules in the United States should be included. The discussion in Section 9.5, which logically would be in the new section, would also be improved if more specific information including details about the modeling tools~ control strategies, or lessons learned were given ~ ~ , _ , _ ~ .
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From page 46... ...
CHAPTER 10: "CONCEPTUAL DESCRIPTIONS OF PM FOR NORTH AMERICAN REGIONS"; APPENDIX E: "CONCEPTUAL DESCRIPTIONS OF SELECTED NORTH AMERICAN SITES" Chapter 10 offers a summary ofthe PM problem in nine regions in North America and comprehensive descriptions of the PM problem in the San Joaquin Valley of California, the Windsor-Quebec City Corridor, and Mexico City. Appendix E provides details on the other six regions.
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From page 47... ...
Presenting the nine region-specific conceptual models in the same figure format as the framework for informing airborne-PM management, but with information in each box reflecting the regional characteristics, may be a more effective way to communicate a coherent story about each region. The figures could replace or augment Tables 10.1, 10.2, 10.3, 10.4, and 10.6, which are tedious and informal in their current form (and contain a number of grammatical and spelling errors)
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From page 48... ...
The five questions bear some resemblance to the eight policy questions (PQs) presented in the draft assessment's executive summary.
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From page 49... ...
Both uncertainty and variability pertain to issues discussed in the NARSTO assessment, and a clearer exposition of their differences would facilitate a better and more realistic understanding of the issues for deicision-makers. To frame Chapter ~ ~ better with respect to the material presented in other chapters, the authors should explicitly relate the recommendations to the policy questions, the policyimplications sections to be added at the ends of other chapters, and the limitations identified in Chapter 10.
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From page 50... ...
Recommendation 2.8 should mention the relationships between sources and health effects, rather than only constituents and health effects. A recommendation for continued and enhanced laboratory studies of aerosol atmospheric chemistry and microphysics is missing.
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