UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D,C. 20460
EPA-SAB-LTR-90-006
September 18, 1990
Honorable Will 1am K. Rellly OFFCEOF
THE ADMINISTRATOR
Admtnlstrator
U.S. Environmental Protection
Agency
401 M Street, SW
Washington, D,C. 20460
Re: CASAC Recommendations on the
Pollutant Standards Index
Dear Mr. Reilly:
During the May 8, 19iO meeting of the Clean Air Scientific
Advisory Committee CCASAC) the members expressed concern over the
adequacy of the EPA's recommended cautionary statements for public
reporting of the air quality Pollutant Standards Index (PSD.
The EPA and CASAC have labored to establish a firm scientific
basis for setting National Ambient Air Quality Standards {NAAQS)
particularly for ozone. However, we realize that it is highly
unlikely that the ozone standard will be met in all regions of the
country in the foreseeable future. Given the present NAAQS, we
anticipate that millions of U.S. citizens will be subject to ozone
levels above the standard for many days each year. The Clean Air
Act, anticipating this possibility, requires that the States adopt
contingency plans to prevent concentrations from reaching
"Significant Harm Levels1 and to take appropriate actions 1f those
levels are reached or are expected to be reached. The plans are
based on two or more "episode criteria" stages, i.e., situations
where the ambient concentrations are or are expected to be
progressively above the NAAQS, EPA establishes significant harm
levels and proposes the episode criteria levels as guidelines for
the States.
The actions taken when Episode Criteria Levels (or Alert
Levels) are reached or expected to be reached Include the issuance
of health advisories (or cautionary statements) to the public.
Since EPA's advice is intended to be applied by local air pollution
agencies in preparing dally air quality summaries which are
disseminated to the media, it is important this advice reflect
current adverse health effects knowledge.
Printed On Rtcycltd Paper
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Attached Is a copy of the cautionary statement from EPA's
guidance document (EPA-450/2-76-013). Neither this table nor the
document as a whole has been updated since 1976. As a result the
health effects statements and cautionary language do not represent
current knowledge, particularly for ozone. For example, ozone
toxicity has been demonstrated to occur in some healthy exercising
individuals at and below the existing Federal standards. Also, the
particulate matter standard refers to the old TSP standard.
Therefore, we recommend that EPA update this 1976 document
with particular emphasis on the cautionary statements. Although
we do not anticipate that this would be major undertaking, we
believe this is an important task that should be done soon. Put
simply, the NAAQS will mainly protect future generations, but
correct cautionary language is needed to minimize health effects
to the present generation.
We look forward to your reply and are willing to assist in
this task as you deem necessary.
cerely,
Roger O. McClellan, D.V.M.
Chai rman
Clean Air Scientific Advisory
Commlttee
Attachment
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TABLE 3. COMPARISON OF PiJ VALUES WITH POLLUTANT CONCENTRATIONS, DESCRIPTOR WORDS
GENERALJ26D HEALTH EF FECTS, AND CAUTIONARY STATEMENTS
INDtX
VALUi
MO
«0
— -MO—
— §a— —
— a
AIR QUALITY
LEVfL
*
_*IO»IFlC*l)f_
HARM
-fMEfHIfNCV-
—WW RHINO —
ALCBT
MftQf NAAOf-
fOLLUTAHT if Vf L«
TO
1M4MM*},
j«A*»
— 1M» —
— ••»-—
— - *»• —
3I§— •
2tO
__ jrs11"— -
____&
»1
tf*4KK*},
Hiftn*
MM
— *UH» —
—MM
— 800 —
— MS —
__ Mb —
0,
CO
H-hMit),
4ftth*3
i?J|
— 4AA— — •
»4,«
__ tJ,0—
__ 100-^
— &* —
0—
«i
lUtOMl,
Ptfafl
1200
MO —
— 400"
1« —
W —
0
H03
|1xl ¥ Mid p«* uni with. *» i n inj
diMiiu ihauld itur indowi «rxJ
«t«id phy Hcvt •*« IK»I G«n«r«l
^«pyl*lian ihould JvQEd i)uldlH>f
^CliVII^,
Chf«i}v *nd pifiQJll wilh iNiicin^
^*4«l til Eking ^IKUM ihould MAy
indiHH* Ind Hduc* phytaci*
actinty.
fl'iooi wilh muling hurl or
HKIMJIOJV »iim«nli ihould nduc*
pliyiitil tutilton and oulduM
*tli«il»
*il
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August 1990
U.S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
CLEAN AIR SCIENTIFIC ADVISORY COMMITTEE
Chaiman
Dr* Roger o. MeClellan, President, Chemical Industry Institute
of Toxicology, P.O. Box 12137, Research Triangle Park,
North Carolina 27709
Members
Dr. Timothy Larson, Environmental Engineering and Science Program,
Department of Civil Engineering FX-10, University of
Washington, Seattle, Washington 98195
Dr. Gilbert S. Omenn, Dean, School of Public Health and
Community Medicine, SC-30r University of Washington,
Seattle, Washington 98195
Dr. Marc B. Schenker, Division of Occupational and Environmental
Medicine, I.E.H.R. Buildling, University of California,
Davis, California 95616
Dr, Mark J. Utell, Pulmonary Disease Unit, Box 692, University of
Rochester Medical Center,, 601 Elmwood Avenue, Rochester,
New York 14642
Dr. Jerome J, Wesolowski, Chief, Air and Industrial Hygiene
Laboratory, California State Department of Health services,
2151 Berkeley Way, Berkeley, California 94704
Dr. George T. Wolff, General Motors Research Laboratories,
Environmental Science Department, Warren, Michigan 48090
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Science Advisory Board Staff
Mr, A. Robert Flaak, Federal Official and Assistant Director,
Science Advisory Board (A-1Q1F), U.S. Environmental Protection
Agency, 401 M Street, SW, Washington, DC 20460
Ms. Carolyn Osborne, Staff Secretary, Science Advisory Board
(A-101F), U.S. Environmental Protection Agency, 401 M Street,
SW, Washington, DC 20460
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