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.
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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
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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.
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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.
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