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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                                       -2-
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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                                       -3-


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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