United States       Science Advisory       EPA-SAB-CAACAC-95-022
      Environmental       Board (1400)          September 1995
      Protection Agency

v>EPA AN SAB REPORT: PHYSICAL
     EFFECTS REVIEW
      DOCUMENTS FOR THE CAA
     RETROSPECTVE BENEFIT-
     COST ANALYSIS
     REVIEW OF THE PHYSICAL EFFECTS
     DOCUMENTS FOR CRITERIA AIR
     POLLUTANTS AND METHODOLOGY
     FOR QUANTIFYING HEALTH EFFECTS
     FOR THE CLEAN AIR ACT (CAA)
     SECTION 812 RETROSPECTIVE
     BENEFIT-COST ANALYSIS

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                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
        1                      WASHINGTON. D.C. 20460
        o
                                 Sentemher 29  1995                 OFFICE OF THE ADMINISTRATOR
                                 septemoer zy, iyyo                  SCIENCE ADVISORY BOARD

EPA-SAB-CAACAC-95-022

Honorable Carol M. Browner
Administrator
U.S. Environmental Protection Agency
401 M Street,  SW
Washington, DC 20460

       Subject:      Clean Air Act Compliance Analysis Council (CAACAC) Physical Effects
                    Review Subcommittee (CAACACPERS) Initial Review Pertaining to the
                    Physical  Effects Review  Documents for Criteria Air Pollutants  and
                    Methodology for Quantifying Health Effects for the Clean Air Act (CAA)
                    Section 812 Retrospective Benefit-Cost Analysis

Dear Ms. Browner:

       In response to the Congressional mandate of Section 812, of the CAA and at the
request of the Agency's Office of Policy Analysis and Review (OPAR) and the Office of
Policy Analysis (OPA), the Clean Air Act Compliance Analysis Council (CAACAC)
Physical Effects Review Subcommittee (CAACACPERS) reviewed the draft physical effects
documents and the methodology pertaining to quantifying health effects for the Clean Air Act
(CAA) Section 812 retrospective benefit-cost analysis.

      The CAACACPERS  met on November 15 and 16,  1994 to receive briefings from
Agency staff and discuss issues with the Agency staff and the public.  In addition, the
CAACACPERS held  a public teleconference on  April 12,  1995  and a public meeting on May
18, 1995  to review Agency drafts of additional sections of its overall analysis of the Section
812 Retrospective Benefits and Costs,  and to finalize the Council's report.  Most of the
findings and recommendations contained in this report were conveyed verbally to  the Agency
staff during the second day of the November 15-16,  1994 meeting.

       We note that the Agency is attempting to respond to a Congressional directive to
conduct a national assessment.  However, it has  been recognized from the outset by all the
parties  involved that the Agency clearly has limited resources provided to it for this daunting
task, and  that many of the actions required of the Agency go beyond the capabilities of
current state-of-the art assessments. Further, while significant human health, human welfare,
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and ecological benefits result from controlling many air pollutants, it is very difficult to
achieve a credible, much less a thorough and unambiguous evaluation, of the human health,
human welfare, and ecological benefits and costs without a sustained program over the long-
term.  In our view, it is clear that the major commitment necessary to make any significant
progress in this area has not yet been made.

       Congress and the Agency have to ask themselves whether they want to commit the
time and resources needed for more comprehensive evaluations.  The Subcommittee believes
that this exercise is worthwhile,  and indeed necessary.  Without evaluation, how can the
Agency and the Congress tell which programs are working, which need attention, and which
need to be cut or expanded?  In  doing such an evaluation,  it is important to give a complete
list of effects.  Where there is any ability to do so, it is important to quantify and monetize
the benefits - at least within an order of magnitude.

       We offer the following specific comments in the belief that constructive advice at  this
stage can help the Agency make significant improvements in the assessment process needed
for the Section 812 and other future mandates.  We also note  that neither Congress nor the
EPA implemented  the CAA in a way designed to expedite evaluation.  It is not surprising,
therefore, that quantifying benefits and costs is so difficult and uncertain at this point.

       a)     Coordination and Management:  The CAA Section 812 retrospective analysis
             and the subsequent prospective analysis are very substantial and important
             exercises.  However, the retrospective study does not presently appear to be
             sufficiently coordinated - either  across the various physical effects  assessments,
             or across all  major model components.  Various EPA offices and researchers
             (and their contractors) have used different strategies to address problems,
             which  limit the linkages in the study and the consistency of presentation.
             Although this study should be pushing the frontiers  of benefits assessment,  it
             is, in fact,  well behind many similar studies performed for other governmental
             entities in terms of coordination, use of available knowledge, and assessment
             of uncertainty.

             The project needs more emphasis on careful and forceful coordination, plan-
             ning, and consistency.  The Agency needs a modeling team leader to  structure
             model frameworks for physical effects quantification and linkages to other
             model components.  The leader can assure that the team identifies  and ad-
             dresses specific critical modeling strategies and issues.

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b)     A Comprehensive Assessment:  In Section 812, Congress specified that the
       assessment should be "comprehensive" and that it should "consider all of the
       economic, public health, and environmental benefits... [emphasis added]."  We
       interpret this to mean that Congress was directing the Agency not to be
       conservative in the sense of minimizing the likelihood that benefits would be
       overstated.  Rather, Congress appears to have been asking the Agency to
       produce an Assessment that was  inclusive of not only well documented and
       measured effects and values, but also those effects and values for which there
       is limited information. In other  words, Congress was asking the Agency to
       take some risks by listing and quantifying effects that are not well documented
       in the literature so as to reduce the likelihood that it would produce an  under-
       estimate of the true benefits.

       With the notable exception  of the analysis of the association between ozone
       and mortality, the draft document is not responsive  to this congressional
       directive.  Rather, it appears to have been prepared with an emphasis on
       statistical and scientific conservatism.  Although this is an  understandable,
       defensible position for the Agency to adopt for many circumstances (for
       example in setting regulations that have to be defended in a legal arena), it
       may not inform Congress about all of the possible benefits (or lack of benefits)
       associated with implementation of the CAA.

c)     Uncertainty Analysis; A major  deficiency in the draft document is the  lack of
       any adequate treatment of uncertainty.  The manner in which  uncertainty is
       treated has important implications for the way in which physical-effects dose-
       response  functions are developed and expressed.  And it is important that the
       Assessment present a clear picture of the degree of confidence, or lack
       thereof, that readers can place on the components of the Assessment.

d)     Ecological Effects;  The effects of air pollutants on human health have
       dominated this analysis thus far,  and it does not appear that ecological effects
       will catch up  within the short time and  limited budget that remain for this
       project. However, one of EPA's  missions is to protect ecosystems from
       adverse effects of pollutants.  By definition, a benefit-cost  analysis is stated in
       terms of dollars.  However, some quantification involves effects that cannot be
       monetized by current methods. Protocols will be needed to express ecological
       and other non monetary values and to compare them to values  expressed in
       monetary terms.  For many of the human health effects, valuation in monetary
       terms may be all that is needed.  However, when ecological effects eventually

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              are addressed, many ecological values (including non-use values) may not
              easily be expressed in monetary terms.  Although ecological effects are
              difficult to comprehensively quantify and value in economic terms, the absence
              of at least a qualitative analysis that is on equal footing with a human health
              analysis will be conspicuous and will leave EPA open to sharp criticism.

       The enclosed report also provides comments on a number of more technical issues
including: the selection of impacts for quantification; omissions, biases, and uncertainty
analyses; sensitivity analysis; and the over-reliance on clinical, as opposed to  epidemiologi-
cal, data.

       Lastly, the Council strongly recommend that the Administrator and the Congress
allocate adequate resources to the Agency and other entities to build a core of expertise to
continue the difficult, but necessary exercise pertaining to quantifying health,  welfare and
ecological effects. It is important that this effort be sustained over the long term.  Such
expertise could logically focus on the many challenges  identified in  this report to you and the
Congress.

       We look forward to receiving  your reactions to  our recommendations as we continue
our reviews of the documents pertaining to the health effects of air toxics, and to ecological
and welfare effects.
                                           Sincerely,
                                   Jr.'Ricnard Schmalensee
                                  Chair, Clean Air Act Compliance
                                    Analysis Council
                                  Science Advisory Board
ENCLOSURE
                                  Dr. Morton Lipr/mAnn
                                  Chair, CAACAC Physical Effects
                                   Review Subcommittee
                                  Science  Advisory Board

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                                        NOTICE

       This report has been written as a part of the activities of the Science Advisory Board, a
 public advisory group providing extramural scientific information and advice to the Administra-
 tor and  other officials  of the 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; hence,  the comments
 of this report do not necessarily represent the views and policies of the Environmental Protection
 Agency or of other Federal agencies.  Any mention of trade names or commercial  products does
 not constitute endorsement or recommendation  for use.

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                                     ABSTRACT

       The Physical Effects Review Subcommittee (CAACACPERS) of the Clean Air Act
Compliance Analysis Council (CAACAC) of the Science Advisory Board (SAB) has
reviewed the Agency's draft physical effects documents and the methodology pertaining to
quantifying health effects of criteria air pollutants for the Clean Air Act (CAA) Section 812
retrospective benefit-cost analysis.  CAACAC responded to five specific questions raised in
the charge to the Subcommittee and also provided more general comments and suggestions
relating to this topic.

        CAACACPERS believes that, despite considerable shortcomings in these documents,
the Agency has laid out a useful framework. The Subcommittee identified a number of
technical issues requiring resolution, and made a number of specific recommendations,
including: more systematically identify and document the selection of impacts to be specifi-
cally included and excluded; conduct sensitivity and uncertainty analyses; more  carefully
balance and specify the uses of epidemiological and clinical data; identify a method comple-
mentary to the standard valuation endpoints, so endpoints that do not lend themselves to
monetary valuation can also be considered equitably in a cost-benefit analysis; rectify
inconsistencies in the selection of coefficients; and investigate mitigation behavior.  The
Subcommittee offers many other comments and emphasizes where fundamental improvements
are needed.

       The Subcommittee strongly  recommends that the Administrator and the Congress
allocate adequate resources to the Agency to enhance its core of expertise to  continue the
difficult, but necessary exercise pertaining to quantifying human health, human  welfare, and
ecological effects over the long term. Such expertise could logically focus on the many
challenges inherent in  cost-benefit analyses.
Key Words: Clean Air Act, Cost-Benefit Analysis, Physical Effects, Air Pollutants, Ozone,
Particulate Matter, Lead, Carbon Monoxide, Sulfur Dioxide,  Nitrogen Dioxide, Economic
Valuation.
                                           11

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                          SCIENCE ADVISORY BOARD
              CLEAN AIR ACT COMPLIANCE ANALYSIS COUNCIL
                PHYSICAL EFFECTS REVIEW SUBCOMMITTEE

 CHAIR
 Dr. Morton Lippmann, Nelson Institute of Environmental Medicine, New York University
 Medical Center, Tuxedo, NY

 VICE-CHAIR
 Dr. A. Myrick Freeman, Department of Economics, Bowdoin College, Brunswick, ME

 MEMBERS AND CONSULTANTS
 Dr. David V. Bates, Department of Health Care and Epidemiology,  University of British
 Columbia, Vancouver, BC, CANADA

 Dr. Gardner M. Brown, Jr., Department of Economics, University of Washington, Seattle,
 WA

 Dr. Timothy V. Larson, Department of Civil Engineering, University of Washington,
 Seattle, WA

 Dr. Lester B. Lave, Graduate School of Industrial Administration, Carnegie Mellon
 University, Pittsburgh, PA

 Dr. Joseph S. Meyer, Department of Zoology and Physiology, University of Wyoming,
 Laramie, WY

 Dr. Robert D. Rowe, Hagler Bailly, Inc., Boulder,  CO

 Dr. George E. Taylor, Jr., Department of Environmental and Resources  Sciences,
 University of Nevada, Reno, NV

 Dr. Bernard Weiss, Department of Health Science, University of Rochester Medical Center,
 School of Medicine and Dentistry, Rochester, NY

Dr. George T. Wolff, Environmental and Energy Staff, General Motors Corporation,
 Detroit, MI

 SCIENCE ADVISORY BOARD STAFF
Dr. K. Jack Kooyoomjian, Designated Federal Official, U.S. EPA,  Science Advisory Board
 (WOOF), 401 M Street, S.W., Washington, D.C. 20460

Mrs. Diana L. Pozun, Staff Secretary,  U.S. EPA, Science Advisory Board (HOOF), 401 M
Street, S.W.7 Washington, D.C. 20460
                                      111

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                         TABLE OF CONTENTS


 1. EXECUTIVE SUMMARY  	  1

-2. INTRODUCTION AND OVERVIEW  	  6

 3. METHODOLOGY AND OVERVIEW OF APPROACH  	  7

 4. OVERALL CONCLUSIONS AND RECOMMENDATIONS	  8
      4.1  Coordination and Management	  8
      4.2  Selection of Effects for Inclusion in the Assessment	  8
      4.3  Selection of Pollutant Species for Analysis	9
    .  4.4  Health-Effects End Points Selected   	  10
      4.5  Omitted Physical Effects	  12
      4.6  Uncertainty Analysis	  12
      4.7  Peer-reviewed literature	  12
      4.8  Additional Issues and Recommendations  	  13

 REFERENCES	R-l

 APPENDIX A - SPECIFIC TECHNICAL COMMENTS  	A-l

 APPENDIX B GLOSSARY OF TERMS AND ACRONYMS	B-l
                                                                                I
                                    IV

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                         1.  EXECUTIVE SUMMARY
       In response to the Congressional mandate of Section 812 (Appendix A, CAA, 1990),
and at the request of the Agency's Office of Policy Analysis and Review (OPAR) and the
Office of Policy Analysis (OPA), the Clean Air Act Compliance Analysis Council
(CAACAC) Physical Effects Review Subcommittee (CAACACPERS) reviewed draft physical
effects documents and the methodology pertaining  to quantifying health effects for the Clean
Air Act (CAA) Section 812 retrospective benefit-cost analysis for criteria pollutants.

       In addition to answering the questions in the Charge (see section 2), the Subcommittee
also focused on the broader mandate from Congress regarding the Section 812 study. The
following highlights summarize the main points of this  review and are offered in  the belief
that constructive advice at this  stage can help the Agency make significant improvements in
the assessment process needed  for the Section 812  and other future mandates.  We also note
that neither Congress nor the EPA implemented the CAA in a way designed to expedite
evaluation.  It is not surprising, therefore, that quantifying benefits and costs is so difficult
and uncertain at this point.  Congress and the Agency have to ask themselves whether they
want to commit the time and resources needed for  more comprehensive evaluations.  The
Subcommittee believes that this exercise is worthwhile, and indeed necessary.  In doing  such
an evaluation, it is important to give a complete list of  effects, and when possible, to
quantify and monetize the benefits - at least  within an order of magnitude.

       The Agency's draft documents reviewed are a first step toward confronting the
challenge of the Congressional  mandates of Section 812 of the CAA of 1990. The following
points are offered as a summary of the findings and recommendations of the Subcommittee as
it dealt with the charge and identified major issues:

       a)     A Comprehensive Assessment: In, Section 812, Congress specified that the
             Assessment should be "comprehensive" and that it should "consider all of the
             economic, public health, and environmental benefits... [emphasis added]."
             With the notable exception of the analysis of the association between ozone
             and mortality,  the draft document is not responsive  to this congressional
             directive.  Rather, it appears to have been prepared with an emphasis on
             statistical and scientific conservatism. Although this is a defensible position
             for the Agency to adopt for many circumstances (for example in setting
             regulations that have  to be defended  in a legal arena), it may not inform
             Congress about all of the possible benefits associated with implementation of
             the CAA.

                                          1

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b)     Coordination and Management:  The CAA Section 812 retrospective analysis
       and the subsequent prospective analysis are very substantial and important
       exercises.  However, the retrospective study does not presently appear to be
       sufficiently coordinated - either across the various physical effects assessments,
       or across all major model components.  Various EPA participants have used
       different strategies to address problems, which limit the linkages  in the study
       and the consistency of presentation.  This study should be pushing the frontiers
       of benefits assessment, bit it is, in fact, well behind many similar studies in
       terms of coordination, use of available knowledge, and assessment of uncer-
       tainty.

       The project needs more emphasis on careful and forceful coordination, plan-
       ning,  and consistency, particularly in the area of modeling.  The  Agency needs
       to assure that specific modeling strategies and issues are identified and ad-
       dressed

c)     Selection of Effects for Inclusion in the Assessment: Balancing  the objective of
       performing a comprehensive analysis against the cost of completing the
       assessment requires a systematic approach to the selection of effects— one that
       focuses resources on the most substantial effects for which literature exists  for
       benefits assessment,  while not ignoring other effects of potential interest or
       concern.  We recommend a more comprehensive approach to the screening  of
       potential effects and  the selection of effects for quantification and valuation.
       Specifically, we recommend:

       1)     Providing a more complete listing and identification of known and
              suspected physical effects.
       2)     Screening known and suspected physical effects to  formally identify and
              focus on the most substantial impacts for which there is  literature to
              develop a damage assessment.
       3)     Employing  a  consistent format for reporting omissions, biases, and
              uncertainties in all study components, and especially in all physical-
              effects components.

d)     Selection of Pollutant Species for Analysis:  The analyses  received initially
       were restricted  not only to the criteria pollutants but, within them, to the
       specific entities monitored in  the ambient air, i.e., SO2, NO2, and the mass
       concentrations of PM10 and PM2 5.  This is inappropriate for sulfur oxides
       (SOJ, nitrogen oxides (NOJ,  and particulate matter (PM). There were

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       essentially no analyses made for the effects of other SOX, such as sulfuric acid
       aerosol and its neutralization products, of other NOX)  such as nitric acid vapor
       and nitrate salts, or of other PM components,  such as trace metals or toxic
       organic particles.

e)     Selection of Health End  Points:  Given that the purpose of this Assessment is
       to estimate the economic value of air quality changes resulting from  the
       implementation of the CAA of 1970, the Subcommittee has reservations  about
       the specific health endpoints selected for detailed quantitative analysis. An
       example of an  effect given too much attention  is reduced lung function follow-
       ing short-term  peaks in exposure to ozone.  In some instances, recent epidemi-
       ological evidence of more adverse effects that are also  more readily monetized
       was overlooked.

f)     Omitted Physical Effects: The documents presented to the Subcommittee
       specifically address only  the health effects of the index pollutants within the
       criteria pollutant category.   In addition to omitting any discussion of other air
       pollutants within the criteria pollutant category, the documents reviewed did
       not address health effects of air toxics, welfare effects, and ecological effects.
       Although  recognizing the limited resources available to EPA to complete this
       project, we urge EPA to perform some sensitivity analyses to prioritize the
       levels of efforts to be invested in air toxics, and welfare and ecological effects
       assessments.
e>
g)     Uncertainty analysis is not adequately treated:  A major deficiency in the draft
       document is the lack of any adequate treatment of uncertainty.  It is not too
       late to make a decision about how uncertainty will be handled in the assess-
       ment.  The manner in which uncertainty is treated has important implications
       for the way in which physical effects dose-response functions are developed
       and expressed.

h)     Ozone:  The Ozone Section of the document is seriously unbalanced.  There is
       an inappropriate emphasis on the findings from clinical studies,  as well as
       questionable interpretation  of the clinical study implications.  The Assessment
       needs to link more closely  the results of the clinical,  field, and epidemiologic
       studies to provide a firmer basis for the health costs of ozone exposures based
       on the exposure-response relationships  from the studies of exposed popula-
       tions.

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i)     Sulfur Oxides:  The stated goal of limiting the analysis to the gaseous sulfur
       oxides has not been explained or justified.  Most importantly, this section does
       not come to grips with:

       1)     The role of SO2 as a precursor of acidic aerosol formation;
       2)     The ways in which SO2 emission controls have affected exposures to
              acidic  sulfate aerosols; and
       3)     The health benefits of the reductions in such exposures.

j)     Paniculate Matter: The mortality effects of particulate matter are likely to be
       the dominant ones in  terms of economic impact. It is unfortunate that the draft
       is incomplete  as it stands in several respects.  First, it needs to account for
       other acute-mortality  studies  that satisfy the selection criteria.  Second, it must
       address the nature and significance of acute mortality in terms of the extent of
       life-shortening for those who die in excess on polluted days.  Third, it should
       consider evidence on  differences in mortality risk across age groups, e g,
       under 65 years vs. 65 and older.  Finally, the biggest deficiency is that it
       ignores the differences in annual average (cross-sectional)  mortality rates
       among communities.

k)     Carbon Monoxide: The section on CO presents, in a clear manner, the
       current information pertaining to the  health risks of exposure. As it notes, the
       most consistent data relating low-level concentrations to health measures come
       from studies based on latency to anginal pain induced by exercise.  Linking
       these findings to mortality from heart disease or to accelerated myocardial
       damage is a difficult speculative exercise, but offers the most reasonable way
       to assess the benefits  of reduced exposure.  If the lower-bound estimate
       includes zero, this can be stated. At  a minimum, the Agency should conduct a
       preliminary assessment using worst-case assumptions to establish an upper
       bound.

1)     Nitrogen Oxides:  It is defensible to exclude aerosol forms of NOX from this
       Section, if they are adequately discussed in Section 3 on Particulate Matter.
       However, such an exclusion needs to be stated more explicitly.  In the case of
       NOX,  that still leaves  all  of the vapor-phase nitrogen oxides to be  discussed in
       this Section.  Thus, this  Section is obligated to review the health effects
       associated with nitric  acid, and possibly nitrous acid (as well as those associ-
       ated with NO2).

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m)    Lead:  This is one of the better-written products provided by the Agency. The
       Subcommittee notes that the Agency's draft document recognizes the broad
       spectrum of lead toxicity and attempts to provide quantitative risk assessments
       for a variety of endpoints.  This aim, however, misses some of the subtleties
       of the lead literature.  Specifically:

       1)     No explicit role is accorded to other measures of neurotoxicity;
       2)     Cross-sectional and other studies fail to exploit the relevant dose-
              response behavioral data;
       3)     Inadequate attention is paid to the interaction of social class and the
              expression of lead toxicity;
       4)     Effects in adults are accorded a narrow point-of-view
       5)     Observations of other effects of lead are important to understanding
              fully the risk factors
       6)     Remobilization of stored lead has been ignored
       7)     The document gives inadequate discussion to the doses and responses
              chosen,  the approximate nature of the functional form, the perils of
              extrapolating very far from the median of the data, and  the question of
              thresholds
       8)     There is no discussion of how changes in mean blood lead levels in
              adults will be predicted as a function of changes in lead  emissions

n)     Ecological Effects: The effects of air pollutants on human health have domi-
       nated this analysis thus far; and it does not appear that ecological effects will
       catch up  within the short time and limited budget that remain for this project.
       However, one of EPA's  missions is to protect ecosystems from adverse effects
       of pollutants.  Protocols  will be needed to express ecological and other
       nonmonetary values and  to compare  them to values expressed in monetary
       terms.  Currently, the documents only discuss valuation in monetary terms.
       For many of the human health effects,  this may be all that is needed. How-
       ever, when ecological effects eventually are addressed, many ecological values
       (including non-use values) may not easily be expressed in monetary terms.
       Although ecological effects are difficult to comprehensively  quantify and
       monetize, the absence of at least a qualitative analysis that is on equal footing
       with a human health analysis will be conspicuous and will leave EPA open to
       sharp criticism.

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                    2.  INTRODUCTION AND  OVERVIEW

       The CAACACPERS met on November 15 and 16, 1994 to receive briefings, and
have discussions with the Agency staff and the public.  The Subcommittee also conducted a
public  teleconference on April 12, 1995 and held a public meeting on May 18, 1995 to
review additional draft documents related to this topic.

       The basic charge presented to the Subcommittee is as follows.

       a)     Are each of the elements of the methodology  developed by EPA sufficiently
             valid and reliable from a scientific standpoint for purposes of the CAA Section
             812 assessments?

       b)     The Congress and the EPA intend that  the CAA Section 812 retrospective
             analysis  should provide the most comprehensive possible statement about
             potential benefits of historical reductions  in air pollution.   This includes
             reporting on the potential significance of  effects for which there may be no
             scientific consensus regarding the magnitude or even the existence of a specific
             effect.  Given this statutory and administrative goal, is the methodology
             developed by EPA sufficiently comprehensive in  terms of plausible physical
             health, welfare, and ecological consequences of exposure to the relevant air
             pollutant?

       c)     If the answer to question 2 (above) is negative, what are the physical outcomes
             of pollutant exposure which the Agency has omitted?

       d),'   For the physical outcomes already included in the methodology paper, as well
       f      as those  which  should be considered for inclusion pursuant to question 2
             (above), are there potentially relevant data pertaining to quantitative or qualita-
             tive estimation  of the effect which should be considered for inclusion in the
             methodology?  What specifically are the scjurces of these data and how might
             they be best utilized?

       e)     What is the strength of the scientific evidence underlying each of the physical
             effects functions or models already included in the methodology paper?  What
             is the strength of each  element of additional scientific evidence suggested for
             inclusion pursuant to questions 3 and 4  above?

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          3.  METHODOLOGY AND  OVERVIEW OF APPROACH

       One question posed to the SAB was whether EPA's proposed approach is suitable for
 quantifying health effects pertinent to Section 812 of the CAA,  with the stated goal of
 providing the basis for a benefits analysis that is "sufficiently comprehensive in terms of
 plausible health, welfare, and ecological consequences of exposure to the relevant air
 pollutant."  Unfortunately the current draft of the Overview document fell short of these
 aims.  The Introduction to the document refers to welfare  and ecological effects as well as
 health effects, and several passages in the document are applicable to these broader aims.
 However, most of the document discusses issues pertinent only  to the quantification of a
 limited number  of effects on human health. We recommend that the title of the Overview be
 changed  to reflect the  limited aims of the present Section  812 Assessment, or that the
 analyses  be broadened to be consistent with the original aims.

       The health overview beginning on page 3 did not accurately describe  the approaches
 used or say anything about the comparative advantage of each.  Toxicological and clinical
 studies are needed to establish causality.  Quantification is generally a combination of
 toxicology (causality, functional form, and sensitive populations) and epidemiology (i.e.,
 "real  world"  conditions and quantification of population response rates).

       The issue of mitigation behavior was not addressed in the general methods section or
 in any of the chapters provided.  Individuals in controlled  exposure  studies cannot mitigate
 exposures,  whereas individuals in real life situations sometimes  can affect their exposures.
 Thus,  the results of clinical studies may overstate damages.  On the other hand, ignoring
 mitigation in epidemiologic studies results in understated damage.  For example, the  number
 of observed health effects per capita for any pollutant level is reduced by mitigation,  but
 mitigation results in  some costs to the affected individuals, such as reduced activities  and
 increased use of medication.

       In redrafting  the overview chapter, one option that  could be considered is to reorga-
 nize by effect rather than by pollutant.  This would naturally lead  to a discussion of real
 world  exposures of mixed pollutants as well as to 'secondary' pollutants  formed in  the
atmosphere.  It may allow for a better assessment of the dose/response relationships
discussed at the end of each chapter and avoid the issues associated with  "double counting"
of effects.  This reorganization of the material would not affect  the air quality analy-
ses/modeling activities also associated with this exercise. Perhaps, more importantly, it
could place the modeling exercise in context, because the actual model outputs of a pollutant
mixture could be used  rather than the pollutant-by-pollutant output.
                                           7

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       4.  OVERALL CONCLUSIONS AND RECOMMENDATIONS

4.1  Coordination and Management

       The CAA Section 812 retrospective analysis and the subsequent prospective analysis
are very  substantial and important exercises.   However, the retrospective study does not
presently appear to be sufficiently coordinated - either across the various physical effects
assessments, or across all major model components.  Various EPA offices and researchers
(and their contractors) have used different strategies to address problems, which limit the
linkages in the study and the consistency of presentation.  Although this study should be
pushing the frontiers of benefits assessment, it is, in fact,  well behind many similar studies
performed for state and other federal agencies, in terms of coordination,  use of available
knowledge, and assessment of uncertainty.

       The project needs more emphasis on careful and forceful coordination, planning, and
consistency.  With consistency,  important linkages will be made between major study
components, appropriate comparisons of costs and benefits can be made,  uncertainty can be
treated in a like manner in all study components, and the level of professionalism will be
consistent in all work elements.

       The Agency needs a modeling team leader to structure model frameworks for physical
effects quantification and linkages to other model components.  The leader can assure that the
team identifies and addresses specific modeling strategies and issues.

4.2 Selection of Effects for Inclusion in the Assessment

       Balancing  the objective of comprehensiveness against the cost of completing the
assessment requires a systematic approach to the selection of effects that focuses resources on
the most  substantial effects  for which literature exists for benefits assessment, while not
ignoring other effects of potential interest or concern.  The draft overview chapter provides a
good, short summary of the approach that was taken, and provides reasonably good justifica-
tion for the options selected within that narrowly defined approach.  However, we recom-
mend a more comprehensive approach to the screening of potential effects and the selection
of effects for quantification and valuation. Specifically, we recommend:

       a)      Providing a more complete listing and identification of known and suspected
              physical effects.

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       b)     Screening known and suspected physical effects to formally identify and focus
              on the most substantial impacts for which literature to develop a damage
              assessment exists.  Ample research to assist with this screening exists.  It is
              important that a clear statement be provided on what is included in the
              quantification and what is not. Substantiation for the selections of the literature
              should also be provided.  The selection process should focus on key health,
              ecological, and welfare impacts that are defended by the  screening, with the
              other effects left to be addressed later, if and when additional resources
              become available.  The Subcommittee would also like to  emphasize that both
              monetary and non-monetary values should be looked at; that is, dollar benefit
              impacts should  not be the only basis for selecting and evaluating impacts.

       c)     Employing a consistent format for reporting omissions, biases, and uncertain-
              ties in all study components, and especially in all physical-effects components.
              This reporting can be in tabular form, listing the omission, bias, or uncer-
              tainty, the direction of bias (if known), and any comments on the potential
              significance of the omissions.

4.3  Selection of Pollutant Species for Analysis

       Another major problem with the overview chapter and companion documents is the
lack of any apparent strategic  planning leading to a comprehensive framework for analysis.
This is evident from the analyses being not only restricted to the criteria pollutants but,
within them,  to the specific entities that are monitored in the ambient air.  This is a  suitable
limitation for carbon monoxide (CO), but not for sulfur oxides (SOx), nitrogen oxides
(NOx), and particulate matter (PM).  Within these pollutant classes, analyses were largely
restricted to the effects of SO2, NO2, and the mass concentrations of PM10 and PM2.5.  As a
consequence, essentially no analyses were made  for the effects of sulfuric acid aerosol and its
neutralization products, of nitric acid vapor and  nitrate salts, of trace metals, or of toxic
organics  as either vapors or particles.

       The reductionist approach taken also complicates and obscures the opportunities to
take some promising approaches to  determining the benefits resulting from the 1970  CAA.
The control costs incurred have largely been associated with source-strength reductions
regarding criteria pollutants themselves and precursors of secondary pollutants.  Imposed on
motor vehicles, power plants,  space heating, and fuel processing, these  controls have led to
known or calculable source reductions in emissions of CO, hydrocarbons, SO2, NOX, and
coarse particles.  The SO2 and NOX reductions have also led to  less well defined,  but
calculable reductions in secondary pollutants such as  SOX and NOX aerosols and ozone  (O3).

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Furthermore, the efforts to control ambient concentrations of O3 and PM have led to
reductions in ambient concentrations of CO, as well as much greater reductions in source
emissions of trace metals and hydrocarbons (as both vapors and aerosols) than any efforts  to
control them through NESHAPS (National Emission Standards for Hazardous Air Pollutants)
as hazardous or toxic air pollutants.  Analyses should be done to show the effects of: a) NOX
source controls on ambient concentrations of O3 and nitric acid; b) the effect of SO2 and NOX
source controls on ambient concentrations of acidic aerosols and on acidic deposition in the
environment; and c) the effects of reductions in  O3 on the formation of acidic aerosols.  Such
an analysis most likely would show,  for example, that the benefits from NOX source control
lie more in their effect on O3 formation, formation of air toxics through photochemical
reactions, and acidic deposition, than on reduction of  health effects directly attributable  to
NO2. The overview chapter is incomplete without a discussion of such interrelationships
between the various pollutants within and among the categories of the National Ambient Air
Quality Standard (NAAQS) and NESHAPS pollutants.

4.4  Health-Effects End Points Selected

       Given that the purpose of this Assessment is to estimate the economic value of air
quality changes resulting from the implementation of the CAA of 1970, we have reservations
about the specific health endpoints selected for detailed quantitative analysis.  An  example of
an effect given too  much attention is the changes in lung function following short-term  peaks
in exposure  to ozone.  No economic data or methods  were identified for estimating the
economic values of such effects.  Furthermore, to the extent that changes in lung  function are
associated with other symptoms and endpoints  that are being modeled, there is a potential  for
double counting of  effects.

       On the other hand, several health end points of potential economic significance were
not  modeled.  Both economic valuation  studies and epidemiological studies support the
development of dose-response functions for a)  respiratory hospital admissions,  minor
restricted activity days,  and acute respiratory symptoms due to exposures to ozone and  b)
asthma, restricted activity days, and  childhood bronchitis due to exposures to paniculate
matter.

       Also, the discussions of health effects for each pollutant were inconsistent  and
incomplete.  The material is presented with limited indication of how it will be used and
integrated into the overall assessment.  For example:
                                           10

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 a)      The introductory chapter noted the limited usefulness of clinical (controlled
        human exposure) studies for this assessment, yet the ozone chapter focused on
        clinical studies with little explanation as to why. The fundamental purposes for
        including controlled-exposure studies are to  establish a basis for the effects
        observed in epidemiologic studies and to establish evidence for effect thresh-
        olds.  The fundamental reasons for not requiring controlled exposure studies
        are the costs to conduct valid exposure analyses (which are not required with
        the use of epidemiologic studies) and the limited usefulness of the endpoints
        that are measured.  These reasons, and others, were not sufficiently discussed.

 b)      The selection of studies, or of dose-response parameters, was inconsistent.  In
        some cases a best study  was selected by judgement, while in other cases meta-
        analysis was used.  In these cases, the criteria for selection of studies for
        inclusion  into the meta-analysis were not  made clear.  A consistent analysis
        framework should be adopted.

 c)      Inconsistent and limited  treatment was given to  portraying the  range of dose-
        response results for use in uncertainty analysis.  In some health sections, the
        highest and  lowest coefficient were reported. In others, a meta-function
        standard  error was reported (or appeared  likely  to be the strategy that would
        be used).  These two approaches have a considerably different interpretation.
        Without consistency  in the treatment of uncertainty, in the physical-effects
        study component, and across all other major analysis components, any propa-
       gation of  uncertainty  may be of limited meaning.

d)     Evidence  for and against thresholds for health effects was often not discussed.
       What are  the assumptions EPA uses for the base case, and why?  What
       sensitivity analysis will be done, and why?  Base-case threshold assumptions
       can be made and defended,  and the analyses  can be conducted  with alternative
       assumptions about what are  practical thresholds  (below which effects may  still
       occur but where the dose-response curve may become very flat or where there
       is little basis to extrapolate existing data to low levels).

e)     Some health effects may overlap.  The treatment of double counting should be
       addressed in each chapter.
                                     11

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4.5  Omitted Physical Effects

       The documents presented to the Subcommittee specifically address only the health
effects of the index pollutants within the criteria pollutant category.  Discussion of other air
pollutants within the criteria pollutant category, health effects of air toxics,  welfare effects
such as effects on forests crops, visibility and materials, and ecological effects was omitted.
Although recognizing the limited resources available  to EPA to complete this project,  we
urge EPA  to perform some sensitivity analyses to prioritize the levels of efforts to be
invested in air toxics, and welfare and ecological effects assessments.  No plan to handle this
challenge was apparent in the Methodology Overview document.  Expert opinion may
provide the only way to approach this challenge.

4.6 • Uncertainty Analysis

       A major deficiency in the draft document  is the  lack of any adequate treatment of
uncertainty. It is now past time  to make a decision  about how uncertainty will be handled in
the assessment. The manner in  which uncertainty is treated has important implications for
the way in which physical-effects dose-response functions are developed and expressed.

       The options for dealing with uncertainty include the formal specification and propaga-
tion of uncertainty using probability distributions  on key variables and applying Monte Carlo
simulations or  other related techniques; the specification of high and low values for key
parameters and the calculation of upper and lower bounds based on them; and sensitivity
analysis.  We prefer the formal  analysis of uncertainty because it generates  much more
information about the overall uncertainty that results from  the combinations of uncertainties
about components of the assessment.  For example, using high and low values will usually
lead to unrealistically wide bounds around the true  value, at least if the individual component
uncertainties  are independent of each other,  as  they often will be.  We also  recommend that
important omissions, biases, and uncertainties be  listed  and their potential significance to the
assessment be discussed.

       We note that the CAACAC also discussed this set of issues in its letter of March 24,
1993 to the Administrator (SAB, 1993).

4.7  Peer-reviewed literature

       The document clearly presents the case  that  the analysis will include data from  some
literature that is not peer-reviewed. While this is necessary in some instances, we would
strongly argue that the window for inclusion of non peer-reviewed literature be restricted to
                                           12

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about two years, sufficient for it to be published.  For example, we suggest limiting the use
of non-peer-reviewed literature to supportive analyses rather than core components.  Clearly,
if a critical component of the  analysis methodology is based on non-peer reviewed literature,
the analysis is suspect.  Some explicit criteria for inclusion and exclusion of "gray" literature
needs to be formulated.

4.8  Additional Issues and Recommendations

       In addition to answering the specific questions in the Charge, the Subcommittee
broadened its scope of coverage to focus on the broader mandate from Congress regarding
the Section 812  study.

       Attempts to quantify the costs of air pollution have been undertaken over the past
three decades, beginning with Ridker and Henning (1967),  Ridker (1967), and Lave and
Seskin (1970).  These efforts led to more active discussion  on the reliability of assuming a
causal relationship from statistical associations. In 1989, a Congressional Research Service
Report to Congress (Congressional Research Service Report, 1989) noted, in the summary:

              "..we conclude  that though there is no doubt that significant health benefits
              result from controlling some air pollutants, it is not currently feasible to
             produce an unambiguous evaluation of the health benefits."

       In Section 812, Congress specified that the Assessment should be "comprehensive"
and that it should "consider all of the economic, public health, and environmental benefits...
[emphasis added]." We interpret this to mean that Congress was directing the Agency not to
be conservative in the sense of minimizing the likelihood that benefits would be overstated.
Rather Congress appears to have been asking the Agency to produce an assessment that  was
inclusive of not only well documented and measured effects and  values, but also those effects
and values for which limited information exists.  In other words, Congress was asking the
Agency to take some risks of overstating benefits so as to reduce the likelihood that it would
produce an underestimate of the true benefits.

       With the notable exception of the analysis of the association between ozone and
mortality, the draft document is not responsive to this Congressional directive.  Rather,  it
appears to have been prepared with an emphasis on statistical and scientific conservatism.
Although this is an understandable, defensible position for the  Agency to adopt for many
circumstances (for example in setting regulations that have to be defended in a legal arena),
it may  not inform  Congress about all of the possible benefits (or lack of benefits) associated
with implementation of the CAA.  The Methodology Overview should discuss  the issues of
conservatism  in the face of limited information about some  effects and describe its approach
to meeting the mandate of Congress to avoid undue conservatism.
                                           13

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       The Council offers the following comments in the belief that constructive advice at
 this stage can help the Agency make significant improvements in the assessment process
 needed for the Section 812 and other future mandates. We also note that neither  Congress
 nor the EPA implemented the CAA in a way designed to generate a database that could be
 used to expedite evaluation.  It is not surprising,  therefore, that quantifying benefits and costs
-in the absence of much relevant data is so difficult and uncertain at this point.

       Congress and the Agency have to ask themselves  whether they want to commit the
 time and resources to future evaluations.  The Subcommittee believes that this effort is
 worthwhile, and indeed necessary.  Without evaluation, how can the Agency and  the
 Congress tell which programs are working, which need attention, and which need to be cut
 or expanded?   In doing such an evaluation, it is important to give a complete list of effects.
 Where there is any ability to do so, it is important to quantify and monetize the benefits - at
 least, by an order of magnitude.

       The Agency should focus its resources on  estimating the important benefits within
 each program.  For example, the Agency can neglect effects that are a factor of ten smaller
 than  the largest effects in a category — They are unlikely to make a significant contribution.
 This rule-of-thumb will allow the Agency to focus its resources on the categories of interest
 and not waste time or effort on categories that would not affect the policy implications of the
 evaluation.

       Currently,  the documents only discuss valuation in monetary terms.  For many of the
 human-health  effects, this may be all that is needed.  However, when ecological effects
 eventually are addressed,  EPA might be forced to conclude that many ecological values
 (including non-use values) cannot easily be monetized. EPA and the Congress will  need
 protocols  for expressing values in non-monetary terms, and for comparing them to those
 values that will be expressed in monetized terms.   In effect, a methodology is needed  to
 decide how to maintain two complementary benefits columns — monetary  and non-monetary
 values.

       Another major problem is that the documents failed to confront the challenge of
 Section 812 in the CAA of 1990.  The overall need is clearly stated in the first two pages of
 the overview chapter (October 11 draft). Thereafter, the focus suddenly narrows  to "effect
 categories that have a direct effect on human health." Furthermore, the balance of  the
 overview chapter,  and the content of the following six Sections on criteria pollutants,  makes
 it evident that analyses are focussed almost entirely on acute health responses, with  consider-
 ably less attention  to  cumulative tissue damage resulting from long-term, low-level exposures
 and their benefits in terms of chronic health-care  costs, lost time from work or school, and
 diminished quality-of-life in people with chronic health damage.

       In  order for EPA to be responsive to the mandate of Section 812 of the CAA,  its final
 report will need to take a broader view of not only human-health effects of criteria  pollut-
 ants, but also  other major class of pollutants and  their effects. These include the effects of

                                           14

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hazardous air pollutants on human health, as well as the effects of air pollution on visibility,
ecosystems, forest and agricultural productivity, and on welfare effects such as soiling and
damage to materials and equipment.  It should be noted that the SAB's CAACACPERS
received draft documents in April, 1995 related to the above topics, discussed them in an
open public meeting on May 18,  1995, and  will provide a future advisory document to the
Agency on these issues.
                                         15

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       Paul, MN.  Arch. Environ. Health 49:366-374.

Schwartz, J., Dockery,  D.W., Neas, L.M., Wypij, D., Ware, J.H., Spengler,  J.D.,
       Koutrakis, P., Speizer, F.E.,  and B.G. Ferris,  Jr.  1994.  Acute effects of summer
       air pollution on respiratory symptom  reporting in children.  Am. J.  Respir. Crit.  Care
      Med. 150:1234-1242.
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 SAB (Science Advisory Board).  1995.  Beyond the horizon: protecting the future with
       foresight. EPA-SAB-EC-95-007.

 SAB (Science Advisory Board).  1995.  Futures Methods and Issues, Technical Annex to
       "Beyond the Horizon: Protecting the Future with Foresight."  EPA-SAB-EC-95-007a.

 SAB (Science Advisory Board).  1994.  Clean Air Scientific Advisory Committee comments
       on air quality modeling  for the section 812 retrospective study. EPA-SAB-CASAC-
       LTR-94-009.

 SAB (Science Advisory Board).  1993.  Science Advisory Board's Review of the Office of
       Policy, Planning, and Evaluation's (OPPE) and the Office of Air and Radiation's
       (OAR) progress on the retrospective study of the impacts of the Clean Air Act. EPA-
       SAB-CAACAC-LTR-93-006.

 SAB (Science Advisory Board).  1990a. Reducing  risk:  setting priorities and strategies for
       environmental protection.  EPA-SAB-EC-90-02.

 SAB (Science Advisory Board).  1990b. Report of the ecology and welfare subcommittee:
       relative risk reduction project.  EPA-SAB-EC-90-02 la.

 SAB (Science Advisory Board).  1988.  Future risk: research strategies for the 1990's.
       EPA-SAB-EC-88-040.

 Small,  K.A., and C. Kazimi.  1995. On the costs of air pollution from motor vehicles. J.
       Transport. Economics and Policy 29:7-32.

 Strand, V., Svartengren, M., Rak, S., and G. Bylin.   1994.   Effects of N02 exposure on
       immediate and late response to inhaled allergen  in subjects with asthma. Am J Respir
       CritCareMed. 149: A154.

 Suter, G.W., II (editor).  1993.  Ecological Risk Assessment, Lewis Publishers,  Boca Raton,
       FL.

Thurston,  G.D., Ito, K., Hayes, C.G., Bates, D.V., andM. Lippmann.  1994.  Respiratory
       hospital admissions and  summertime haze air pollution in Toronto, Ontario: consider-
       ation of the role of acid  aerosols. Environ. Research  65: 271-290.

Thurston,  G., Lippmann, M., Bartoszek, M.,  and J. Fine.  1994. Summer haze associations
       with asthma exacerbations, peak flow changes, and respiratory symptoms  in children
       at a summer asthma camp  In: Program Abstracts of the Sixth Conference of the
       International Society for Environmental Epidemiology: Research Triangle Park, NC
       September 18-21, 1994.  Abstract 227.
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Thurston, G., and P. Kinney.  1992.  Daily respiratory hospital admissions and summer haze
       air pollution in several New York metropolitan  areas.  Am. Rev. of Respir. Dis.
       145(4:2):A429.

U.S. EPA.  1995.  Revised air quality criteria document for ozone and related photochemical
       oxidants (CASAC Review Draft,  February, 1995). Environmental Criteria and
       Assessment Office,  U.S. EPA Office of Research and Development.

U.S. EPA Memorandum. 1994. CAACAC Review of Section 812 Retrospective Analysis.
       from R.D. Brenner, Director, Office  of Policy Analysis and Review and R.D.
       Morgenstern, Director,  Office of Policy Analysis, to D.G. Barnes, Director, Science
       Advisory Board, October 5, 1994

U.S..EPA.  1986.  Ozone  Criteria Document.  EPA-600/8-84-020aF-eF.  Washington, DC

U.S. EPA.  1995.  Revised air quality criteria document for ozone and related photochemical
       oxidants: CAS AC review draft.  Environmental Criteria and Assessment Office, U.S.
       EPA, Ofice of Research and Development.

U.S. GAO.  1994. Air Pollution: EPA's Progress in Determining the Costs and Benefits of
       Clean Air legislation, U.S. General Accounting Office, Report to Congressional
       Committees.

Ware, J.H. Spengler, J.D., Neas, L.M., Samet, J.M., Wagner, G.R., Coultas, D.,
       Ozkaynak, H. and M. Schwab.  1993.  Respiratory and irritant health effects of
       ambient volatile organic compounds: the Kanawha County Health Study.  Am. J.
       Epidemiol. 137: 1287-1301.

White, M.C., Etzel, R.A., Wilcox, W.D., and C. Lloyd. 1994.  Exacerbations of childhood
       asthma and ozone pollution in Atlanta.  Environ. Research 65:56-68.

Winneke, G., Hrgina,  K.,  and  A. Brockhaus.  1982.  Neuropsychological studies in children
       with elevated tooth-lead concentration.  Int. Arch. Occup. Environ. Health 51:  169-
       183.

Yule,  W., Lansdown, R. Millar, I., and M. Urbanowicz.  1981. The relationship between
       blood lead concentration, intelligence, and attainment in a school population:  a pilot
       study. Dev. Med. Child Neurol. 23: 567-576.
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             APPENDIX A-SPECIFIC TECHNICAL COMMENTS

 OZONE

 General Comments

       The Ozone Section of the document is seriously unbalanced. The specific reasons for
 this conclusion are provided in the detailed critique that follows, but the imbalance is
 primarily the consequence of inappropriate emphasis  on the findings from clinical studies, as
 v/ell as questionable interpretation of the clinical study implications. The clinical studies are
 very important, because they confirm  that the functional and symptomatic effects reported in
 field studies of natural populations engaged in outdoor recreational activities and/or vigorous
 work schedules can be seen  under rigorously controlled experimental conditions. They are
 also important, because they demonstrate that concurrent lung inflammation, not detectable in
 field studies, occurs and that it persists during repeated daily exposures despite the attenua-
 tion of functional and symptomatic responses.  This provides mechanistic support for the
 epidemiological associations observed  between repeated exposures and the exacerbation of
 asthma.  By more closely linking the results of the clinical, field, and epidemiologic studies,
 a revised document could provide a firmer basis for the health costs of ozone exposures
 based on the exposure-response relationships from the studies of exposed populations.

       In this revised discussion, the authors need to  recognize that the paradigm for the
 quantitative assessment of the pulmonary function responses of humans to exposure to ozone
 has recently shifted,  as agreed by CASAC (Clean Air Scientific Advisory Committee)
 consensus during their meeting in July, 1994 and by the WHO-EURO  (World Health
 Organization, European Region) Working Group on Air Quality Guidelines at their meeting
 in Bilthoven, The Netherlands, October,  1994 (Lippmann,  1995, personal communication).
 There is now a body of credible data from field studies on human populations in natural
 settings to establish  the nature  and extent of human pulmonary function responses to ambient
 ozone exposures, and their uncertainty.  In this new paradigm, the  findings  in controlled
 laboratory studies provide support for  the observed effects  in natural populations, rather than
 the other way around, as stated in the  draft chapter.

       The effect of ozone on  mortality remains to be established, but  warrants careful
 attention. Although  the Kinney and Ozkaynak (1991)  studies report positive ozone effects,
 other mortality  studies have not found  a  statistically significant ozone relationship.   EPA does
 not address  how it would use the Kinney  and Ozkaynak results.  Will the coefficient from
 LA or  NY be used?  Or would they be averaged? Will these values be the central coefficient
 (ignoring or giving little of no weight  to other negative studies)?  What confidence will be
given to the selected coefficients and why?

       The macro-epidemiology studies are noticeably absent, including those for restricted
activity days (e.g., Ostro et al.,  1989; Portney et al,  1986), acute respiratory symptom days
 (Krupnick et' al., 1990), and respiratory  hospital admissions (Burnett et al., 1994; Thurston

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etal., 1992, 1994, Pope, 1991; Schwartz, 1994a,b).  This omission is noticeable because
these endpoints and studies are easier to use than the selected controlled exposure studies,
these endpoints and studies are regularly used in other benefit analyses, and because many of
these endpoints and studies are included in the particulate matter chapter.  Related to these
points is our concern  with the emphasis in this Section of the draft on physical effects of
uncertain significance for human health and for which there is little or no empirical data on
people's willingness to pay to avoid these effects.

       As noted in the prior CAACAC Subcommittee review on transport and transformation
modelling, a potentially major issue arises when attempting to reconstruct historical O3
exposure via simple urban plume (box) models.  Historical emissions of NOX were higher
than today. Therefore the spatial distribution of NOX emission densities in urban  areas would
be different today in the absence of controls, and thus the  spatial distribution of maximum
hourly O3 values would also be different.  Simple urban plume  models may not adequately
capture this shift in O3 and therefore may improperly  characterize the control versus no-
control population exposure difference.  One possible approach  is to use the 03 predictions
from the RADM (Regional Acid Deposition Model) model exercise to predict the control/no-
control ratios of O3 exposure and then use these ratios to adjust current (present day) O3
levels.  This would provide a spatially averaged  O3 exposure difference for use in retrospec-
tive  analyses.

       This section also needs other significant revisions.  It must address: standard issues of
thresholds; double counting; omissions, biases, and uncertainties; and the selection of central
dose-response function coefficient values.

Specific Comments

Page 1-3: Line 9 from top: "the average changes in lung function are generally small and are
a matter of controversy in regard to their medical significance." As noted below, the issue is
whether an FVC  (Forced Vital Capacity) change is indicative of induced inflammation.
Fuller discussion is needed.

Page 1-8: bottom of page: A  recently presented study by Thurston et al. (1994).   A full text
of this manuscript would be important, as the abstract does not  mention all the important
findings. The authors studied asthmatic children at a summer camp for a week in three
consecutive years. The children  had to report to an office (where there was doctor and  a
nurse) if they felt they needed medication.  Air pollutants were measured at the camp.  The
usual decrements in lung function with 03 levels were noted,  but in addition there was a
monotonic  relationship between the requests for medication and the ozone level at concentra-
tions lower than 100 ppb. This study should also be included in Table 1-3.

Page 1-12: Section 1.2.2: This extended discussion of symptoms does not include any
mention of whether the induction of symptoms is important.  Does it indicate that inflation
has occurredT Why does the FVC fall early in ozone exposure? As it stands, it is clinically

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incomplete.  See below.  Also, the review should cite the recent paper on symptoms in
children participating in the Harvard six-cities study (Schwartz et al., 1994).

Page 1-12: A new section is needed to summarize and discuss the evidence of induced
inflammation in the human lung after ozone exposure.  On page 1-21 in section 1.2.7, it is
noted, that :  "Indications of ongoing tissue inflammation of subject exposed to O3 have been
reported in several studies."  This is far too weak a statement for the contemporary evidence.
The time course of the induced inflammation has been well summarized by Koren and Devlin
and their associates ( Koren, et al., 1991).  This reference is useful in this regard.

Page 1-22 (first paragraph): The following statement is quoted from the criteria document:
"However, the time course of this inflammatory response and the O3 exposures necessary  to
initiate it, have not yet been fully elucidated" . This is entirely unsatisfactory in the light of
present evidence (Koren, et. al., 1991). Furthermore,  the statement at the end of the second
paragraph on page 1-22 referring to Devlin's work states: "However these results have not
yet been fully evaluated."   What does this mean?  We recommend that the authors revisit
these issues with experts at HERL (Health Effects Research Laboratories) laboratories of
EPA.  One would have expected an up-to-date and sophisticated discussion of these issues in
this document.

A more suitable summary  would state:

       "It has been well established that an early effect of ozone is to cause an inflammatory
       response in the human lung. The pattern of increases in the cells in bronchoalveolar
       lavage specimens after ozone exposure in normal subjects, followed by the appearance
       of inflammatory mediators for as long as 18 hours after the exposure, has been
       convincingly shown."
       The relationship between the onset of symptoms and the reduction in FVC, with the
onset of inflammation is less clear. It appears that the magnitude of induced function defect
and the severity of the inflammatory response are not closely associated (Frampton et.  al.,
1994); if this is the case, then the question arises of whether the use of the function test
response as a guide to safe exposure level is appropriate.  What is the clinical significance of
an induced inflammatory response? in normal subjects? in"asthmatics?  These question  must
be directly addressed.

       It should also be noted that the effect of ozone (120 or 240 ppb) in inducing a
inflammatory response in the nose of asthmatic and non-asthmatic subjects has been studied
(McBride et.  al.,  1994).  This showed that an inflammatory response was found in asthmatic
but not in normal subjects.

Page 1-14: Section 1.2.5:  Aggravation of existing respiratory disease:
This section  should contain a synthesis of information on asthma. The statement quoted here

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 from the 1986 Ozone Criteria Document is inappropriate, as it is seriously out of date.  The
 Draft Ozone Criteria Document (U.S. EPA, 1995) recently submitted by EPA to CASAC
 includes a full and up-to-date summary of the known effects of ozone; the clinical and
 epidemiological data bases are well covered.  Additionally,  a synthesis of present data on
 asthma would have told the reader:

       a)     Exacerbations of asthma (including fatal asthma) are now believed to be due to
             acute inflammation in the airways  (Laitinen et. al.,  1993; Kuwano et. al.,
             1993).

       b)     The early and prolonged induction of airway  inflammation by ozone is well
             documented.

       c)     Although in quantitative terms the  function test response and the bronchial
             reactive response in asthmatics to ozone may  be similar to that in normals, the
             effect in asthmatics is exerted on an already depressed level of function, and
             an already aggravated airway responsiveness.  Thus the inference invited from
             the quotation from the 1986 Ozone Criteria Document, that ozone is not more
             of a risk to asthmatics than to normals, is not an accurate representation of the
             circumstances.   Kreit's  1989  paper (Kreit et al.,  1989) is quoted, but misinter-
             preted.

       d)     Based on the nasal lavage studies,  asthmatics show  an  inflammatory response
             to ozone that is not shown by non-asthmatics  (McBride et. al., 1994).

       e)     There is now strong epidemiological evidence (see below) that  asthma is made
             worse by existing ozone levels.

       In the light of these observations, the comment on Page 1-28  in the second line:
"However,  there is no consensus about the magnitude of the difference in sensitivity between
asthmatics and other individuals" should be  deleted.

Page 1-17:  Section 1.2.6: This section is seriously out of date. References in Tables 1.5 and
 1.6 include several as abstracts which  have  now been completely published (White,  et. al.,
 1994; Cody,  et. al.,  1992; Thurston, et. al., 1994; Burnett et. al., 1994; and Lipfert and
Hammerstrom,  1992), and one that is  not mentioned (Schwartz, 1994a).  To  summarize this
very large bank of epidemiological data:

       a)     The Ontario data has now been  analyzed by four different groups of investiga-
             tors (Bates and Sizto, 1987):  Lipfert and Hammerstrom, 1992: Thurston et.
             al.,  1994b: and Burnett et. al.,  1994). All find a strong association of respira-
             tory hospital admissions with ozone.
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       b)     Although in the eastern Great Lakes region, ozone is associated with peaks of
              acid aerosol, several studies indicate that the primary effects relationship is
              with ozone.  PM10 effects appear to be additional and separate.

       c)     In Burnett's analysis of admissions to 168 hospitals in Ontario between 1983
              and 1988 (Burnett, et. al., 1994), there is a monotonic relationship between
              respiratory  admissions and ozone the day before.  These data should be used
              in economic estimates and assumed to apply in the Northeast of the continent.

       d)     White's data (White et. al., 1994) show a direct association between hospital
              emergency visits and ozone levels in Atlanta.  The levels of acidity here are
              not much different from those in New Jersey.  Together with Cody's data
              from eight New Jersey hospitals (Cody et. al., 1992), the conclusion should be
              drawn that ozone at levels below 120 ppb is aggravating asthma.

       e)     Schwartz's recently published data on hospital admissions for pneumonia in the
              elderly in Detroit (Schwartz, 1994a) are supportive.  He has been able to show
              separate effects for PMio and for ozone.
       This document should have analyzed the Lipfert, Burnett, Thurston,  Cody, and White
and Schwartz data, and presented a synthesis of ozone impact on emergency visits and on
hospital admissions as a basis for cost estimates.

Page-1-22: Section 1.2-8: The effect of ozone on macrophage is noted here, but this should
be under Section  1.1. The discussion is also incomplete because the reader is not told the
possible significance of this experimental finding.  Does it indicate that ozone levels might
affect the incidence or severity of pneumonia? (See comment under Page  1-17 above on
Schwartz's recent study of pneumonia in Detroit).

Page 1-22: Section 1.2.9: It is true that animal-exposure data are important for estimating the
likelihood of chronic effects of ozone.  But the point should be mentioned that it  is difficult
to extrapolate from rat data to humans, because the rat  lung has been shown to be less
sensitive to ozone than the human lung, probably because a lower concentration of ozone is
delivered to the periphery of the rat lung than to the human.  See Hatch et.  al. , (1994) for a
recent discussion of this.   This important work was done at the HERL in  North Carolina.

Page 1-28: Section 1.4.1.  It is surprising to find the development of complex formulae to
calculate pulmonary function test responses to ozone, together with symptomatic responses in
Section  1.4-2, when the strength of the epidemiological data has been denied.  An individual
does not go to a hospital  emergency department, much less get admitted,  complaining of a
2% loss of FEV, (Bates,  1992).  This misplaced emphasis represents a serious lack of
balance.
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SULFUR OXIDES

       The stated goal of restricting this section to the gaseous sulfur oxides has not been
explained or justified. It could be justified by a disclaimer that the particulate sulfur oxides
would be fully covered in Section 3 - Particulate Matter, if that were indeed the case. This
issue will be addressed further in our comments on Section 3. In any case, the stated goal is
not followed because an extensive,  if inconclusive text on the historic PM-SO2 epidemiology
is included in  this section.

       Most importantly, this section does not come to grips with: (1) the role of SO2 as a
precursor of acidic  aerosol formation; (2) the ways in which SO2 emission controls have
affected exposures to acidic sulfate aerosols;  and (3) the health benefits of the reductions in
such exposures.  Without such considerations, this section is  woefully inadequate.

PARTICULATE MATTER

General Comments
       There is little doubt that particulate matter (PM) causes health problems.  The
questions are:  Which particles?  Which effects?  And what is the dose-response relationship?
Recent reviews which address particulate matter should be cited, and the following points
should be noted:

       a)      In  the past, PM dose-response studies have focused on total PM10 and health
              effects (or even TSP), although a few had started to look at constituents of
              PM10.  EPA takes this approach, as well, in its draft  document.

       b)      In  the past year, considerable new evidence allowed investigation into the
              relative significance of some constituents (e.g., SOX aerosols),  and

       c)      This  issue should be  investigated by the Agency.  There will still remain issues
              of  attribution, verification, and double counting; however, considering the
              newer literature will  provide a much clearer picture of the likely health effects.

       The mortality effects are likely to dominate in terms of economic impact.  It is
unfortunate that the draft is incomplete as it stands in several respects.   First, it needs to
account (as does Table 3-13) for other acute-mortality studies that satisfy the selection
criteria.  Second, it  must address the nature and significance  of acute mortality in terms of
the extent of life-shortening for those who die in excess on polluted days. Third, it should
consider evidence on differences in mortality risk across age  groups, e g., under 65 years  vs.
65 and older.  Finally, the biggest deficiency  is that it ignores the differences in annual
average (cross-sectional) mortality rates among communities (Dockery  et. al., 1993, Pope et
al, 1995).
                                          A-6

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       The secondary aerosols formed in the atmosphere from SO2 and NOX precursors can
often account for 25 to 40% of the ambient PM. While the NOX aerosol health effects
literature is meager and inconclusive, the SOX aerosol literature is not.  Extensive evidence of
health effects associated with exposure to strong acid aerosol (H+) exists,  and even more
literature relating exposures  to health effects associated with exposures to  S04= exists.
Whether SO4= itself produces such effects is an open question, because ambient SO4= may
simply indicate the presence of H+. In any case, SO4= often shows closer associations to the
effects, than do simultaneous measurements of PM10 or PM2 5, and is  often a major mass
fraction of PM2 5.

       The Sox aerosol health-effects literature cannot be ignored in the benefits analysis.
Either it must be included in a revised Section 3, or alternatively in a revised Section 2.

     .  Although a consensus regarding the effects of PM on certain health endpoints,
including mortality, is rapidly evolving, a major issue still remains regarding the  application
of the results to a retrospective benefits analysis. Specifically, how are we to estimate
historical PM,0 concentrations in  the U.S. given the fact that we only  have TSP (Total
Suspended Particulates) values  for most of the past 25 years? One approach is to bound the
PM10 values over time. A reasonable lower bound on historical  PM10 is to assume that it  has
remained constant at present-day  values.  An upper bound can be derived  assuming that
present-day PM10 to TSP ratios, on a city-by-city basis, have remained constant over time.
This would allow a reconstruction of historical PM10 based on historical TSP.  This latter
approach  represents an upper limit on historical PM10 because it  is certain  that emissions of
larger  particles (> 10 /xm) have been controlled more than emissions of smaller particles
(< 10  /*m) over the past 25  years in the U.S.

       An alternative approach would be to use historical measurements of sulfate to assess
fine particle concentration trends  over time.  Particulate sulfate measurements do  exist over
time,  as well as site-specific  comparisons with various fine-particle mass measurements.
This analysis presumably would fall within the bounds described  above. The danger with
this approach is that it could be misconstrued as supportive of a hypothesis that sulfate
particles  are the causative agent.

CARBON MONOXIDE

       The CO document presents, in a clear manner, the current information pertaining to
the health risks of exposure.  As it notes,  the most consistent data relating low-level  concen-
trations to health measures come from studies based on latency to anginal pain induced by
exercise.  Linking these findings to mortality from heart disease or to  accelerated  myocardial
damage is a difficult speculative exercise but offers the most reasonable way to assess the
benefits of reduced  exposure.

       Behavioral effects, which played a large role in the earlier CO  literature, have
diminished in~ importance with the inability of investigators to reliably  reproduce such effects.

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 Exercise performance in healthy subjects suggests diminished capacity at environmentally
 relevant CO levels, but the data are rather sparse and the question has been pursued only at

 high levels of activity in standardized situations.  The document should point out the potential
 importance of modifications in voluntary exercise.

       Overall, this Section seemed on track and well done until it concluded (p. 4-14, #1
 lines, 5, 6) that: "A concentration- response function based on the Allred et al. (1989) data
 will not be developed and used in  the current assessment."  Why not?  The results of this
 multi-center controlled human exposure study are important, along with the results of other
 related and consistent clinical lab studies,  because they address cardiac ischemia, a significant
 risk to health, and show that subjective responses are correlated with objective measures.
 Specifically, the time to  onset of angina is linked to changes apparent on electrocardiograms.
 Much, weaker and less conclusive results were used for this purpose in  other Sections. If the
 lower-bound estimate includes zero, this can be stated.  At a minimum, the Agency should
 conduct a preliminary assessment to either establish order of magnitude values, or a worst
 case bounding analysis .

 NITROGEN OXIDES

 General Comments

       As noted in Section 2 on Sulfur Oxides, it is defensible to exclude aerosol forms of
 NOX from this Section, if they are adequately discussed in Section  3 on Paniculate Matter.
However, such an exclusion needs to be stated more explicitly.  In the case of NOX, that still
leaves all of the vapor-phase nitrogen oxides to be discussed in this Section.  Thus,  this
 Section  is obligated to review the health effects associated with nitric acid,  and possibly
nitrous acid (as well as those associated with NO2).  It fails to do so and  is, therefore,
 deficient.  The draft is also deficient in its treatment of NOX chemistry.  It  should be noted
 that the only relevant equilibrium is between NO and NO2, not the other  nitrogen oxides.

      The conclusion that outdoor NO2 concentrations are "poor predictors of personal
exposures" ignores the recent work done in Los  Angeles (Neas, et al., 1991).  They co-
located NO2 passive monitors both indoors and outdoors and regressed these weekly values
against personal badge values.  The outdoor values accounted for between 40 and 50 percent
of the personal exposure; the remainder was attributed to indoor values.  These recent results
temper the conclusions of the chapter.  Additionally, recent European work on NO2 showing
detrimental effects on asthmatic children, should also be looked at  by the Agency (Moseler et
al, 1994).

 Detailed Comments

      Page 5-2: Section 5.2-1:  The recent work from HERL showing that preexposure to
NO2 in healthy women increases the effect of a subsequent  exposure to O3,  should be cited

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(Hazucha et. al., 1994,). It is important to note that NO2 pre-exposure exerts an effect not
only on the subsequent 03 effect on FEY^ but also in increasing the airway responsiveness.

       The recent Swedish work should be noted (Strand et. al., 1994), even though it is still
only in Abstract Form.  In studies of 18 asthmatics sensitive to birch or timothy grass,
-exposure to 0.5 ppm NO2 at rest for 30 minutes was shown to increase the late asthmatic
reaction when the subject was subsequently exposed to the allergen. The immediate reaction
was unchanged.

Page 5-9: Section 5.3:
       The reasons for thinking that asthmatics may be a sensitive group have been described
above.  In an 8-month panel study of asthmatics in Denmark, Moseholm and his colleagues
(Moseholm et.  al., 1993) found that both SO2 and NO2 exposures were associated  with
worsening  of the  asthmatic state.  This paper might be quoted.

Page 5-11: Last paragraph:

       Surely it would be useful to develop a risk estimate regardless of the sources and
nature of the exposure to NO2. It  will never be possible to determine exactly, for each
individual in society, what made up the cumulative exposure.  The quotation from the  NO2
Criteria Document at the head of this page stresses the consistency  of the observations, and
recent  work provides a basis for estimating the exposures.  Outdoor N02 can only add to
indoor levels.

       The Subcommittee agrees that some recent data showing an  increased risk of asthma
exacerbation in Birmingham, England,  associated with closer residence to a  major  highway
(Edwards et. al.,  1994) do not allow identification of the nature of the hazard (which might
as well be  PM10 as NO2), far less an estimate of exposure.  Nor does the note that the
asthma associated with exposures to the dust from soybeans in Barcelona only occurred after
several days of NO2 being elevated (Castellsague et. al., 1992) permit a risk estimate.  The
significant  correlation that was reported between outdoor NO2 levels and hospital emergency
visits for acute  respiratory disease  in the elderly in Vancouver (Bates et al.,  1990) can be
used in cost estimates, however, because the regression can be computed.

       If none of these strategies is deemed solid enough to compute a damage associated
with outdoor NO2 levels, the document should end with some such  statement as:

       The contemporary data indicate that raised NO2 levels (both indoor and outdoor) are
       associated  with adverse health outcomes. Currently, the data are not solid enough to
       permit a damage  estimate -  but it is clear that any damage estimates which ignore
       completely the effects of N02 are necessarily underestimates.

       With the above caveats, this section provides a useful and generally well-balanced
review of a notoriously difficult pollutant.

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LEAD

General Comments

       This is one of the better-written products provided by the Agency. The Subcommittee
notes that the Agency's draft document recognizes the broad spectrum of lead toxicity and
attempts to provide quantitative risk assessments for a variety of endpoints.  This aim,
however, misses some of the subtleties of the lead literature.  Specifically:

a)     No explicit role is accorded to other measures of neurotoxicity:  The document
focuses on IQ (Intelligence Quotient) as "the predominant measure of neurotoxicity."  Other
indications of adverse central nervous system (CNS) actions are recognized indirectly, but no
explicit role is accorded them. For example, Section 6.1 emphasizes effects on hematopoie-
sis, but fails to mention the even more critical effects on neuro-chemistry. We do not expect
a comprehensive review of such data in a document of this kind, but they should be
acknowledged given that the primary developmental effects are expressed in  behavioral
toxicity.

b)     Cross-sectional and  other studies fail to exploit the relevant dose-response behavioral
data:  Section 6.2.2-2.2 (Cross- Sectional and Other Studies) mentions conduct disturbances
as one criterion of toxicity, but fails to cite some relevant data.  For example, Needleman et.
al, (1979) demonstrated a  clear dose-response relationship between tooth lead levels and
items on a teacher rating scale describing such disturbances.  Yule et. al. (1981) observed a
similar relationship.  Such data provide  transparent connections between exposures and
adverse effects that supplements the IQ data. The data of Needleman et. al.  (1990a,b;  1979)
which show a correlation between  tooth lead values in the early primary grades and subse-
quent success in high school, are also important guides to the evaluation of risks and
benefits.

c)     Inadequate attention is paid to the interaction of social class and the expression of lead
toxicity:  Although  mentioned (page 7), inadequate attention is paid to the interaction of
social class and the expression of lead toxicity.  It is not solely the Cincinnati studies (Carson
et al., 1989; Rae, 1983) that demonstrate such a phenomenon. Winneke et al, (1982),  in
Dusseldorf, reported similar results. Such interactions should be included in any attempts to
describe benefits.

d)     Effects in adults are accorded a narrow point-of-view: Section 6.2.2.1 (Effects in
Adults) focused on evidence for a  threshold.  In  other sections, a Lowest Observed Adverse
Effect Level (LOAEL), which is actually the criterion under discussion,  was modified by
uncertainty factors.   Why was lead treated differently?
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 e)     Observations of other effects of lead are important to understanding fully the risk
 factors:  Section 6.2.3 notes a relationship between higher prenatal blood lead levels and
 reductions in gestational age and birth weight.  Such observations are important not only for
 estimating lead's contribution to infant mortality but for examining the contributions of lead
 to reduced IQ scores.  Lowered gestational age and birth weight are risk factors  for a variety
 Of developmental disturbances.

 f)     Remobilization of stored lead has been ignored:  The document notes the transfer of
 lead from mother to fetus but does not fully describe the hazards of excessive bone stores in
 the mother which may be recruited during pregnancy.  Similarly, the release of bone stores
 of lead during aging may provide  another kind of risk.

 g)     Dose-response relationships:  The dose-response relationships are the key to benefits
 estimation, because this provides the basis for quantification.  The documents give inadequate
 discussion to the doses and responses chosen and the appropriate caveats.  The approximate
 nature of the functional form, the  perils of extrapolating very far from the median of the
 data,  and of the question of thresholds need to be discussed. Much more attention should be
 given to  discussing the quantification of the dose-response function and what legitimate uses
 of the equations are.

 h)     Modeling adult lead uptake and changes in blood lead levels: There is no discussion
 of how changes  in mean blood lead levels in adults will be predicted as a function of changes
 in lead emissions.

 ECOLOGICAL EFFECTS

       The following comments are based on our review  of several reports from  an  outside
 contractor (Industrial Economics, Inc.) that reviewed valuation methods and their applicabil-
 ity to this Assessment.  These reports were provided to the Subcommittee as background.
 Their review was not part of the charge to Subcommittee.

 General  Comments

       The objective of the documents delivered prior to  the review meeting was to present
 the elements of the methodology by which the EPA will provide a comprehensive analysis of
 the potential benefits and liabilities from changes in air quality  in the United States.  The
 research  is designed to evaluate in  an aggregate and comprehensive manner impacts due  to
 air quality on: (i) human health; (ii) natural and intensively-managed ecosystems (and at-risk
cohorts); (iii) visibility; and (iv) materials.  The documents provided by the Agency  excluded
 items ii - iv. Comments are offered relative to items ii-iv in anticipation of how the Agency
plans  to develop the methodology.

       As it often appears to happen in other cost-benefit analyses, human health has
dominated this analysis thus far; and it does not appear that ecological effects will catch up

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within the short time and limited budget that remain for this project. However, one of EPA's
missions is to protect ecosystems from adverse effects of pollutants.  No other Federal
agency has this as a primary mandate (U.S. EPA/SAB,  19905), whereas other agencies  share
the mandate to protect human health. It seems likely that this Assessment will once again
highlight our lack of information to quantify ecological effects with adequate certainty.

       This Subcommittee is concerned that natural resource valuation is likely to be simply
an addendum to the evaluation provided for human health.  If so, it would inaccurately
reflect the mission of the Agency, the overwhelming data demonstrating a linkage between
human health and sustainability of natural  resources, and the intrinsic value of natural
ecosystems (U.S. EPA/SAB, 19905).

       Although consideration of issues of economic valuation is beyond the scope of the
Subcommittee charge from the Agency, the Su5committee offers this additional commentary
for consideration.  Ecological effects are difficult to comprehensively quantify  and value in
economic  terms.  However, the a5sence of at least a qualitative analysis that is on equal
footing with a human health analysis will 5e conspicuous and will leave  EPA open to sharp
criticism.  Quantitative valuation clearly has difficulties associated with translating ecological
effects into monetary terms in the valuation process (U.S. EPA/SAB, 1990a).  Congress and
the EPA Administrator should be reminded of this continuing deficiency.  Although the  value
assigned to a single human life and other morbidity effects might at first appear to be so high
as to overshadow any other possi51e cost-5enefit  categories, some people 5elieve non-use
ecological values might be significant relative to  the monetary  value of human  lives — if only
enough effort was expended to fully valuate ecosystem functions in monetary and non-
monetary  terms.  Until such efforts are supported, Congress will not be  presented with a
truly comprehensive view of the benefits associated with implementing the CAA.  Quantita-
tive ecological risk assessment (Suter, 1993) might provide an approach  to deriving a
valuation methodology.   We encourage the Agency not to ignore this quantitative methodol-
ogy.

       The effort to address physical (including biological and ecological)  effects can best
proceed if the exposure modeling is done in a way that complements the effects research.  In
the past, most of the exposure modeling has been done from the perspective  of the atmo-
spheric sciences community,  whereas most of the effects research  is done from the perspec-
tive of the biologists. The isolation of the disciplines has resulted in analyses that often  can
not be linked in the respective camps.

       Finally, it was clear that the Congress anticipated that the research  would be compre-
hensive, exhaustive and integrative. However,  the picture that  emerged in  the documents and
discussions was one of isolated, fragmented activities without a cohesive framework.   Given
the scope  of the project,  it is imperative that the  fragmentation be replaced with an approach
that is far more integrated.  Otherwise, inadequate results are predictable.
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 Specific Comments

       Specific comments on quantification and assessment of ecosystem impacts follow:

 a)  Wildlife: Wildlife were not mentioned in the background documents provided to the
 Subcommittee, even though surface-water quality and fisheries were mentioned. If human
 health is a concern regarding  rural air pollution, it seems reasonable to believe that at least
 some mammalian and perhaps non-mammalian wildlife species might also be adversely
 affected by rural air pollution.  Although little is known about wildlife toxicology, it is likely
 that there are adverse effects of air pollution on wildlife. This assessment should acknowl-
 edge the probability of some adverse effects; therefore, some positive expected benefits of
 reduced air pollution,  benefits of reduced air pollution will not be counted).

 b)  Pollutants: For aquatic ecosystems, acidification  (an indirect effect of SOX and NOJ and
 air toxics are much more important than CO,  O3 and PM.  The background document
 appeared to implicitly recognize this.  The roles of SOX and NOX should be made clear.  And
 the importance of airborne toxics (e.g., metals in addition to lead) to ecosystems should be
 emphasized.  Ecological risk assessment techniques that recently have been developed at Oak
 Ridge  National Laboratory appear to be the most appropriate methods for evaluating the
 effects of air toxics that are transferred into aquatic ecosystems.  Such techniques were not
 mentioned in the documents available to the committee.

 c)  Ecological services: It is  difficult to decipher how this issue is being handled, and we
 encourage  that the document be specific.  Ecological  systems provide "services" that need to
 be addressed including nutrient cycling, water processing, air cleansing, recreation, wildlife
 habitats,  pollutant degradation, etc.  These are benefits that society derives and values.

 d)  Food-web  transport: Ecological systems process pollutants in the environment.  In
 many cases, the processing degrades chemicals to innocuous forms.  In other cases, transport
 and transformation of chemicals through terrestrial and aquatic food webs result in increasing
 toxicity and in biomagnification. Notable cases are mercury (via methylation) and polycyclic
 aromatic hydrocarbons (via food web contamination).

 e) Geographical scale: The  scale of the evaluation was not discussed, and the  issue is not
 trivial.  Many of the pollutants have residence times that result in their distribution being
 hemispherical and/or  global (e.g., ozone,  mercury,  trace organics).  If the scale of the
analysis is  simply regional or  continental,  the assessment process will not capture the
 significance of changes outside of the continental United States.

 f) At-risk cohorts:  It is widely recognized that there is a standard of error or margin of
 safety used as a basis for air quality standards,  particularly with respect to human health
 (i.e., appropriate to protect sensitive members of the population).  The same concept is also

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appropriate in some aspects of welfare effects but is handled in separate legislation (e.g.,
PSD legislation, Endangered Species Act).  The emphasis was supposed to be on at-risk
cohorts in both human and non-human effects.  Although at-risk cohorts were supposed to be
considered in evaluating human and non-human effects, the ecological-effects reports ignored
the concept of at-risk  cohorts.

g)  Aggregate effects across pollutants: Will the effort appropriately address interactions
among pollutants? The literature strongly suggests that a pollutant-by-pollutant analysis is
inaccurate and too simplistic. This also applies to human-health and welfare effects.

h)  Concept of sustainability:  Ecological sustainability involves "impacts on the environ-
ment that are irreversible or of long duration compared to human perspectives" (U.S.
EPA/SAB, 1990b, p.  35); furthermore, the sustainability of human  activities is determined
by the  resilience of the ecological systems on which economies depend (Arrow et al., 1995).
In the ecological literature, this concept has emerged as one means of developing a better
appreciation for the value of ecosystems. We encourage EPA  to be cognizant of this
approach.
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