S&B.-CASAC-87-009 UNITED STATES ENVIRONMENTAL PROTECTION AGENCV WASHINGTON, D c. 20460 Deeerrber 15, 1986 The Honorable Lee _M. Thomas Administrator U.S. Environmental Protection Agency Washington, DC 20460 Dear Mr. Thomas: The Clean Air Scientific Advisory Committee (CASAC) has completed its review of two documents related to the de^uelopraent of National Anbient Air Quality Stardards {NA&QS) for Participate Matter and Sulfur Oxides, These two documents are the 1982 _AirQuality Criteria for _PartjLculate_ Hatter arrf__Sulfur__Qtii<3esy and the 1986 Se_cpn_d Addendum to Air Quality Criteria for Particulate Matter and _Sulfur C&ides__(l9S2)_, both prepared by the Agency's Environmental Criteria and Assessment Office (EOQ). The Ccnraittee was impressed with the efforts of the staff of ECAO in preparing a well written, integrated and thorough review of recent relevant scientific studies. The Committee unanimously concluded that this 1986 Addendum, along with the 1982 Criteria Document previously reviewed by CASAC, represent a scientifically balanced and defensible summary of the extensiw scientific literature on these pollutants. » Several important issues are discussed in the 1986 Addendum which the Committee believes should be emphasized, ifiese issues were raised during our review of recent studies which relate primarily to guidance at the lower bounds of the ranges for the standards* Ihese studies include the recent reanalyses of the London mortality data, two episodic lung function studies in the United States and the Netherlands, and the comparison of respiratory symptoms and puljmonary function lewis of children living in six U.S. cities. Further discussion of these studies and reanalyses, as well as a more detailed discussion of the basis for the Committee's conclusions, are contained in the attached report* Ihe Ccmtiittee also reviewed the Staff Papers for particulate matter and for sulfur cxides at the October 15-16, 1986 meeting, and is preparing separate reports reflecting its conclusions and recommendations on each of these two documents. ------- „ 2— Thank you for the opportunity to present the Conroittee's views on these important public health issues. Since rely, / J i\i^>. cc: A. James Barneg Lester Grant Vaun Newill Craig Potter Terry Yosie Morton Chairman Clean Mr Scientific Advisory Conroittee ------- SAB-CASAC-87-009 SUMMARY OF MMQR SCIENTIFIC ISSUES AND CASAC CONCLUSIONS ON THE 19S6 ADDENDUM TO THE 1982 PAKTICULATE MA1TER/SULFDH OXIDES (PM/SQx) C1ITERIA DOCUMENT The Committee concentrated its review on newer studies and analyses which relate primarily to guidance on the lower limit of the proposed ranges for the standards. In general, the Committee believes the Criteria Document -Wdendum has appropriately summarised and interpreted the designs, analyses and conclusions of studies that should be considered in the standard setting process. The following is a brief chapter by chapter summary of issues that the Committee wishes to emphasise, or which require further clarification, Chapter JL; ..Introduction In general, this chapter provides an excellent summary of the physical and chemical properties and ambient measurement methods for PM and SO^. However, the chapter could be strengthened by inclusion of a discussion of direct reading itonitors for particulate mass concentrations including beta attenuation, light scattering, or other techniques which may be the dominant measurement techniques in 'the States in the future. This was discussed at the December 1985 CASAC meeting, with ensphasis on the need to jrove to automated and continuous monitoring for particles. Chapter 2; Respiratory Tract Depositionand Fate The presentation in this chapter could be expanded by clarifying the discussion concerning the concept of impaired lungs and the deposition that would occur there as opposed to that in normal subjects. Further, the discussion of broncho-constriction being protective (Svartengren et al., 1984) and the discussion of other types of altered breathing patterns could be made clearer, perhaps by reorganizing this information by specific points. Chagter _3; Epidemiology Studies We wish to emphasize several studies and analyses discussed at the October 1986 CASAC meeting. One of these studies•(Dassen et al.) should be integrated into this chapter, as was recognized by Agency staff in their remarks at the October 1986 meeting. 1) The two episodic lung function studies show a consistency of results in Steubenville, Ohio (Dockery et al.} and Ijmond, Netherlands (Dassen et al.), lending credence to reported effects of a mixture of PM and sulfur oxides (SQX) on respiratory function in children. This is consistent with the earlier work of Stebbings. These studies provide a relatively sensitive indication of possible short term physiological responses of uncertain health significance to PM. the roles of exposure times ar*3 duration of functional decrement need tetter definition. ------- -2- 2) The London mortality studies, including recent analysis by Agency staff, provide strong evidence that particulate matter is mom closely associated with daily mortality than sulfur dioxide concentrations. The criteria document should recharacterise distinctions made between "likely" and "possible" effects levels for establishing upper bounds, 3) The Six-Cities study has reported that cough and bronchitis are twice as prevalent in children living in cities with PM^o in the range of 40-60 ug/m-3/ in comparison to cities with a range of 20-30 Chapter 4 \_ Controlled Hunan Exgosuge_Studies of _sg_2 Health Effects Although this chapter was well done, the Committee suggests that it be strengthened by Modifying its existing discussions and by addition of further discussion and tabular 'material concerning short term exposure effects presented by Drs. Horatman and Polinsbee at the October 1986 CAS&C meeting. Conclusion The 1986 Addendum to tlie 1982 Mr Quality Criteria Document on PM/SQx was prepared by EPA at the request of CASAC for the purpose of updating the knowledge of recent scientific studies and analyses. The Committee commends the Agency staff for its efforts in preparing a concise and well written document. The Addendum summarizes tey firriings from the earlier documents and provides a reasonably complete summary of newly available information concerning particulate matter and sulfur oxides, with major emphasis on evaluation of human health studies published since 1981. The Committee unanimously concludes that this 1986 Addendum, with the incorporation of the changes noted above, represents a scientifically balanced and .defensible summary of the extensive scientific literature on these pollutants. These documents fulfill the requirements under section 108 of the Clean Air Act as amended, which requires that the document (s) "...shall accurately reflect the latest scientific taiowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare..." from particulate matter and sulfur oxides in the ambient air. ------- |