SAB-CASAC-86-008
January 2, 1986
Honorable Lee M. Thomas
Administrator
U.S. EnvirOTnental Protect ion
Agency
Washington, D.C. 20460
Dear Mr. T2wnas;
The Clean Air Scientific Advisory Ccnmittee (CfiSAC) met on
December 16-17, 1981 to hold a preliminary discussion with EPA staff
and raeafcers of the public on health effects information relating to
particulate matter that has,become available since the Ccomittee's last ••
official review of such data, this new scientific information includes:'
respiratory tract regional deposition patterns? epidaniolo§ical studies
of mortality and morbidity effects associated with both short-term and
long-term particulate exposures; and health effects related to acid
aerosols.
The Conraittee's preliminary view of this body of data is that it
does not require a. fundamental alteration of the structure of the proposed
particulate standards at this tine or ftindainentally change our understanding
of the mechanisms by which particulate exposures affect public health.
These new data are consistent with naany earlier findings. However, they
lead the Cormittee and many members of the public to have serious concern
as to whether the current proposed ranges of interest are as scientifieally
stipportable as they ^re in November 19S1 when they were last ejcanined by
CASAC, Mich of- the new data suggest the need to focus consideration on
standards at or perhaps below the low. ends of the ranges proposed in the
March 20, 1§84 Federal Register Notice.
Tb resolve these and other issues raised by the new studies, CASAC
the following i
» That the staff of the Environmental Criteria and Assessment
Office prepare an addendum to the existing Mr Quality Criteria
Docua»nt for Sulfur Qaddes/Barticulates and evaluate the
scientific adequacy of new health effects data for particulate
matter and their implications and relevance to standards-setting.
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* That the staff of the Office of Air Quality Planning and
Standards prepare an addendum to the existing Staff Paper for
Particulate Matter and evaluate, in particular-, whether the
recently available scientific studies alter their thinking
on the proposed ranges of interest.
CftSAC believes that the Agency would be well served by the prepara-
tion and public and scientific review of such documents because these
data will strengthen the scientific basis of policy decisions you must
on partieulate matter; in addition, the Agency will demonstrate its
capacity to update its scientific assessments through a process which
CftSAC and the public believe is credible. It is not the Caattittee's intent
preparation of these addenda needs to result in a re-eKHnination of
all major issues previously evaluated. Rather, we hope that the Agency
can develop thai in a targeted and esqpeditious manner that would not
significantly delay the promulgation of particulate standards*
Finally, CASAC recommends that EPA formally evaluate in an issues
paper the host of scientific issues pertaining to acid aerosols and their.
applicability to setting a separate standard for this class of pollutants.
There is a growing body of 'data supporting the view that acid aerosols
are associated with health effects that, a general partieulate standard
nay not protect against. In addition, studies reported
quantitative response relationships in concentration levels beginning to
be applicable to standard setting. Because the tine requirements for
developing an acid aerosols assessment are likely to be longer than those
needed for preparing the criteria document and staff paper addenda, the
CASAC reccnmendg that EPA plan' a separate schedule Cor this issue and not
delay the partieulate standapf prcrayuLgation timetable,
the Cemnittee would appreciate hearing your views on its reccmnenda-
tions.
Sincerely,
Lipproann
Chairman
Clean Mr Scientific advisory
Ccmnittee
cc: A. James Barnes
Donald Ehreth
Charles Elkins
Gerald Emison
Lester
Terry fosie
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