United States Of flea of th* Administrator EPA-SAB-CASAC-89-0 19
Environmental prediction 5cl«nc« Advisory Board May 1983
Agency ' Washington, DC 204SO
Report of the
Clean Air Scientific
Advisory Committee
(CASAC)
Review of the NAAQS
for Ozone: Closure on
the OAQPS Staff
Paper (1988) and the
Criteria Document
Supplement (1988)
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ABSTRACT
This Is tha report of the EPA'a Clean Air Scientific Advisory
Committee (CASAC) on its review of Agency's draft
"Air Quality Criteria Document Supplement (1988)" and the "Review
of National Ambient Air Quality Standards for Ozone: Assessment
of Scientific Technical Information (198S)11. documents
were reviewed in public session on 14-15, 1988, with the
Committee reaching the conclusion that the provide an
adequate scientific and technical basis for EPA to retain or revise
primary secondary national ambient air quality standards for
ozone.
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NOTICE
This report has been written as part of the activities of the
Science Advisory Board, a public advisory group providing
extramural scientific information and advice to the Administrator
and other officials of Environmental Protection Agency. The
Board is structured to provide a balanced expert assessment of
scientific matters related to problems facing the Agency. This
report has not, been reviewed for approval by the Agency? and,
nance, the contents of this report do not: necessarily represent the
views and policies of the Environmental Protection Agency or other
agencies in the Federal Government. Mention of trade or
commercial products does not constitute a raeonmendation for use.
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U.S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY
AIR SCIENTIFIC
Chairman
Dr. Roger o. McClellan, President, Chemical Industry Institute
of Toxicology, Research Triangle Park, North Carolina
Members
Dr. Timothy Larson, Environmental Engineering Science Program,
Department of Civil Engineering, University of Washington,
Seattle, Washington
Dr. Gilbert s. Omenn, Professor and Dean, School of Public Health
and Community Medicine, University of Washington, Seattle,
Washington
Dr. Marc B. Schenker, Director, Occupational and Environmental
Health Unit, University of California, Davis, California
Dr, Mark J, Utell, Professor of Medicine Toxicology,
Co-Director, Pulmonary Disease Unit, University of Rochester
School of Medicine, Rochester, New „ork
Dr. Jerome J. Wesolowski, Chief, Air and Industrial Hygiene
Laboratory, California Department of Health, Berkeley,
California
Dr. George T. Wolff, Principal Scientist, General Motors
Research Labs, Environmental Science Department,
Warren, Michigan
Executive Secretary
Mr. A. Robert Flaak, Environmental Scientist, Science Advisory
(A-101F), U.S. Environmental Protection Agency,
401 M Straat, SW, Washington, D.C. 20460
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U, s. Environmental Protection Agency
Science Advisory Board
Clean Air Scientific Advisory Committee
chairma
Dr» Roger 0, McClellan, President, Chealeal Industry Institute of
Toxicology, Research Triangle Park? North Carolina
IJembers
Dr. Eileen G. Brennan, Professor Emerita, Plant Pathology
Department, Cook College, lutgera University, New
Brunswick, New Jersey
Dr. Edward D. Crandall, Chief, Division of Pulmonary and Critical
Care Medicine, Cornell University Medical College, New
„ork» New York
Dr. James D. Crapo, Duke University Medical Center, Department
of Medicine, Division of Allergy, Critical Care and
Respiratory Medicine, Durham, North. Carolina
Dr. Robert Prank, Professor of Environmental Health Sciences,
The Johns Hopkins School of Hygiene and Public Health,
Baltimore, Maryland
Dr. A. Myrick Freeman III, Resources for the Future, Washington,
District of Clombia
Dr. Jay S. Jacobson, Plant Physiologist, Boyca Thompson Institute,
Ithaca, New York
Dr. Jane Q« Koenig, Research Associate Professor, Department of
Environmental Health, University of Washington,
Seattle, Washington
Dr. Timothy Larson, Environmental Engineering and Science Program,
of civil Engineering, University of
Washington, Seattle, Washington
Dr. Morton Lippmann, Professor, Institute of Environmental
Medicine, New „ork University Medical Canter, Tuxedo,
New York
Dr. M. Morgan, Head, Department of Engineering and
Public Policy, Carnegie-Mellon University, Pittsburgh,
Pennsylvania
Dr. D. North, Principal, Inc., Lo« Altos,
California
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Dr. Gilbert S. Onienn, Professor of Medicine and of Environmental
Health, Dean, School of Public Health and Community
Medicine, University of Washington, Seattle, Washington
Dr. Robert D, Rowe, Senior Vice President, RCG/Hagler, Bailly,
Inc., Boulder, Colorado
Dr. Marc B. Schenker, Director, Occupational and Environmental
Health Unit, University of California, Davis, California
Dr» George E. Taylor, Jr., Group Leader, Physiological Ecology,
Environmental Sciences Division, Oak Ridge national
Laboratory, Oak Ridge, Tennessee
Dr. Mark 3, Utell, Professor of Medicine and Toxicology,
Co-Director, Pulmonary Disease Unit, University of
Rochester School of Medicine, Rochester, New „ork
Dr. Jerome j. Wesolowski, Chief, Air Industrial Hygiene
Lab, California of Health, Berkeley, California
Dr. George T. Wolff, Principal Scientist, General Motors Research
Laboratories, Environmental Science Department, Warren,
Michigan
Executive Secretary.
Mr. A. Robert Plaak, Environmental Scientist, Science Advisory
Board (A-101F), U.S. Environmental Protection Agency,
401 M Street, SW, Washington, DC 20460
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D C. 20460
May 1. 1989
The Honorable William K. Reilty
Administrator
U. S. Environmental Protection Agency
401 M Street, SW
Washington, DC
Dear Mr. Reilly:
I am pleased to transmit via this the advice of the Clear Air Scientific
Advisory Committee (CASAC) concerning the National Ambient Air Quality
Standards for Ozone. CASAC has reviewed and offered comments directly to EPA
staff on the EPA criteria document "Air Quality Criteria for Ozone and Other
Photochemical Oxidants (1986)," the "Criteria Supplement (1988)."
and the Office of Air Quality Planning and Standards staff position paper "Review
of the Air Quality Standards for Ozone Assessment of Scientific
and Technical Information (1988)" and related support documents.
CASAC previously closure on the 1986 Criteria Document. At a
meeting held on December 14-15, 1§88» CASAC came to closure on the "Criteria
(1988)" and the 1988 Staff Position Paper and concluded
that they provide an adequate scientific basis for EPA to or primary
and secondary standards for ozone. While reaching closure at this time, the
Committee did an on the effects resulting
from 6-pius hours of ozone exposure, providing evidence of the possible need for a
standard with a §-8 hour averaging time. However, it was the Committee's view
that It would be time enough of information would be
published In journals to receive full review and, thus, be suitable for
in a CASAC concluded such information can better be
considered In the next review of the ozone standards.
CASAC did not a on of the staff
position papef recommendation that "the range of 1-hour average ozone levels of
concern for standard setting purposes is 0.08-0.12 ppm for a primary standard,"
The opinion of the CASAC Ozone Review Committee with regard to
the upper range of the standard with eight individuals favoring a range with an
of 0.12 ppm, an in the range of
0,10-0,12 ppm, four individuals favored an upper bound natun no higher than
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0.10 ppm, and one Individual abstained from offering an opinion. Several
Individuals an of 0,12 ppm as well as all of the other
individuals who favored a lower value for the upper end of the range expressed the
view that at 0.12 little or no margin of safety. As you are aware,
the margin of safety Is intended to provide protection against adverse effects which
have not yet uncovered by research and effects whose medical significance is
a matter of disagreement. Finally, several members of the subcommittee favored
development of a standard with a more statistically robust upper bound on the
annual distribution of ozone concentrations rather than reliance on the current
expected exceedance form of the standard. While the Committee offers no further
advice on what form the Agency should consider, we would caution you against
any form which alters the degree of health protection afforded by the current
standard,
CASAC substantial discussion of the of what are or are not adverse
health effects. This discussion by the presentation of this issue in the
staff position paper. Within CASAC there diversity of opinion; some members
felt that healthy Individuals experience adverse effects when ozone exposure induced
any of the as moderate (i.e., >10% decrement in FEV or
mild to moderate respiratory symptoms) in the staff position paper, while a^few
members believed that adverse effects would not be experienced until ozone
induced more severe effects (i.e., >20% decrement In FEV and moderate to
severe respiratory symptoms). The view of some Individuals %n this matter was
influenced by recognition that resolution of the adverse health issue
represents a blending of scientific and policy judgments and, thus, we feel it
appropriate to inform you of the range of our views on this matter.
Of particular concern to CASAC Is the potential for arising from
exposures to ozone with daily concentrations at or near 0.12 ppm for periods
of §-8 hours co-exposure to other pollutants. This concern Is due to air
quality analyses which have shown that even in which do not repeatedly
the standard, remain to 0.12 ppm for
several hours per day for extended periods of time in summer. There was concern
based on recent controlled hyman exposure, epidemiology and toxicology studies.
that such prolonged exposures could result In increased respiratory impairment.
Further, for exposed to these ozone concentrations over a lifetime, the
possibility that chronic Irreversible effects mav result Is of concern, although such
changes hav« not been demonstrated.
The Committee noted that the Criteria Document Supplement failed to cite
and discuss a group of "ecological" epidemiologies! of the of
on various measures of human health such as for respiratory
or of problems. Although studies
have obvious limitations in establishing cause and relationships, they have
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certain strengths which can aid In regulatory decision-making. Studies of this type
should be discussed and evaluated In future criteria documents as a complementary
source of information.
While reaching closure on the staff paper recommending a i-hour
standard, CAS AC that the increased support for research
that will prove an Improved scientific basis for evaluating the need for standards
with multi-hour or times. Clearly, the obvious, research on this
critical environmental health issue must be supported now In order for results to
be for consideration In the next 5-year review cycle. CAS AC has
enumerated these research needs In some detail in a September 1987 submission
to the Agency. The Committee feels these research recommendations are still
valid and should be incorporated as expeditiousiy as Into the Agency
research program.
CASAC did not reach a consensus opinion on endorsement of the staff
position recommendation of "a 1-hour averaging time In the range
of 0.06-0.12 ppm" for a secondary standard. The CASAC Ozone Welfare Effects
matter a divided opinion; two favored a
range with an upper value of 0,12 ppm, three favored an upper value of less than
0.12 ppm, five favored an upper value of 0.10 ppm. The Committee noted
that the form of the standard was of critical importance In protecting against
ozone effects on vegetation. The Committee was of the opinion that a cumulative
seasonal standard would be more appropriate than a 1-hour standard and felt that
such a standard could be developed. CASAC favored issuance of a cumulative
seasonal standard form assuming its development would not further the
standard setting process. If this form of standard cannot be developed in time for
the current 'eview, the Committee is of the opinion you should give serious
consideration to setting a 1-hour secondary standard with a maximum
concentration of 0.10 ppm. The Committee took of the lack of information
on the of on ecosystems and urged support for research to
In closing, I would like to briefly comment on CASAC's failure to reach a
consensus as to the appropriate range for setting the ozone standards. This lack
of consensus Is reflective of major deficiencies In our knowledge regarding health
and welfare of long-term exposure (beyond a few hours) to ozone. The
data bas« is very targe and adequate for knowledgeable individuals to reach
agreement on the effects of exposure to In the for
setting a i-hour standard. However, there Is not an on the
of or to as
whether such may produce chronic health effects. This is especially
troubling long-term to occur in many parts of the
United and involve many millions of people and thousands of of crop
and lands. As a result, continues to be concern for the public health
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and welfare threat which may be posed by chronic exposure to ozone. It is
critical that the data base on health and welfare effects to multiple hour.
seasonal and lifetime exposures of ozone be increased through an accelerated and
expanded research effort. This must be done so that future considerations of
ozone standards will derive from a stronger scientific base.
CAS AC that your statutory responsibility to set standards requires
public health policy judgments In addition to determinations of a strictly scientific
nature. While the Committee is willing to further advise you on the ozone
standards, we see no need, in view of the already extensive provided, to
review the proposed ozone standards prior to their publication in the Federal
Register. In this Instance, the public comment period will provide sufficient
opportunity for the Committee to provide any or that
may be necessary.
CASAC would appreciate being kept informed of progress on establishing
revised or new ozone standards and plans for research on ozone effects. Please
do not to contact me if CASAC be of further assistance on this
matter.
Sincerely,
O. McCWIan, D.V.M.
Chairman, Clean Air Scientific Advisory
Committee
ROMrewb
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