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i EPIDEMIOLOGY AND AIR POLLUTION Committee on the Epidemiology of Air Pollutants Board on Toxicology and Environmental Health Hazards Commission on Life Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1985
ii NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the Councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Research Council was established by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of further- ing knowledge and of advising the federal government. The Council operates in accordance with general policies determined by the Academy under the authority of its congressional charter of 1863, which establishes the Academy as a private, nonprofit, self-governing membership corpora- tion. The Council has become the principal operating agency of both the National Academy of Sci- ences and the National Academy of Engineering in the conduct of their services to the government, the public, and the scientific and engineering communities. It is administered jointly by both Academies and the Institute of Medicine. The National Academy of Engineering and the Institute of Medicine were established in 1964 and 1970, respectively, under the charter of the National Academy of Sciences. The study reported in this publication was conducted at the request of and funded by the U.S. Envi- ronmental Protection Agency under Contract 68-02-4073. Illustrations: Cover, Dr. Clarence C. Gordon, (c) National Geographic Society; page 20, Jodi Cobb, (c) National Geographic Society; page 36, Dr. Arnold Brody, National Institute of Environmental Health Sciences; page 88, Dr. Clarence C. Gordon, (c) National Geographic Society; page 126, Jodi Cobb, (c) National Geographic Society; page 162, Martin Rodgers, (c) National Geographic Soci- ety; page 190, Barrie Day School. Available from: National Academy Press, 2101 Constitution Ave., N.W., Washington, D.C. 20418.
iii Committee on the Epidemiology of Air Pollutants MAUREEN M. HENDERSON, Chairman, Department of Epidemiology, University of Washington, Seattle, Washington PHILIP J. LANDRIGAN, Co-Vice-Chairman, Environmental Sciences Laboratory, Department of Community Medicine, Mt. Sinai Medical Center, New York, New York PAUL D. STOLLEY, Co-Vice-Chairman, Clinical Epidemiology Unit, University of Pennsylvania, Philadelphia, Pennsylvania JOHN C. BAILAR, III, Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, and Office of Disease Prevention and Health Promotion, Department of Health and Human Services, Washington, D.C. DAVID V. BATES, Department of Health Care and Epidemiology, University of British Columbia, Vancouver, British Columbia, Canada INGE F. GOLDSTEIN, Division of Epidemiology, School of Public Health, Columbia University, New York, New York ROGENE HENDERSON, Inhalation Toxicology Research Institute, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico MARVIN S. LEGATOR, Division of Environmental Toxicology, Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, Texas PAUL J. LIOY, Institute of Environmental Medicine, New York University Medical Center, New York, New York SAMUEL C. MORRIS, Department of Energy and Environment, Brookhaven National Laboratory, Upton, New York PAUL R. PORTNEY, Resources for the Future, Washington, D.C. CARL SHY, Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, North Carolina JOHN D. SPENGLER, Department of Environmental Science and Physiology, Harvard School of Public Health, Boston, Massachusetts BAILUS WALKER, Department of Public Health, The Commonwealth of Massachusetts, Boston, Massachusetts National Research Council Staff PETER H. GANN, Project Director DEVRA LEE DAVIS, Executive Director, BOTEHH MARY ELLEN SCHECKENBACH, Staff Assistant J AMES LANEAR, Administrative Secretary NORMAN GROSSBLATT, Editor BARBARA MANDULA, Consultant
iv Board on Toxicology and Environmental Health Hazards GERALD N. WOGAN, Chairman, Department of Applied Biological Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts DONALD HORNIG, Co-Vice-Chairman, Harvard School of Public Health, Boston, Massachusetts PHILIP J. LANDRIGAN, Co-Vice-chairman, Environmental Sciences Laboratory, Department of Community Medicine, Mt. Sinai Medical Center, New York, New York JOHN DOULL, Department of Pharmacology, University of Kansas Medical Center, Kansas City, Kansas HERMAN N. EISEN, Department of Biology and Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts EMMANUEL FARBER, Department of Pathology, University of Toronto, Toronto, Ontario, Canada RICHARD MERRILL, School of Law, University of Virginia, Charlottesville, Virginia EMIL PFITZER, Department of Toxicology and Pathology, Hoffmann-La Roche Inc., Nutley, New Jersey LIANE B. RUSSELL, Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee ELLEN SILBERGELD, Toxics Program, Environmental Defense Fund, Washington, D.C. PETER SPENCER, Institute of Neurotoxicology, Albert Einstein College of Medicine, Bronx, New York Ex Officio ROY E. ALBERT, Institute of Environmental Medicine, New York University Medical Center, New York, New York GARY P. CARLSON, Department of Pharmacology and Toxicology, Purdue University School of Pharmacy and Pharmacal Science, Lafayette, Indiana THOMAS CHALMERS, Mt. Sinai Medical Center, New York, New York ARTHUR B. DUBOIS, John B. Pierce Foundation Laboratory, Yale University, New Haven, Connecticut ALAN M. GOLDBERG, School of Hygiene and Public Health, The Johns Hopkins University, Baltimore, Maryland MAUREEN M. HENDERSON, Department of Epidemiology, University of Washington, Seattle, Washington
v ROGER O. McCLELLAN, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico DANIEL B. MENZEL, Department of Pharmacology, Duke University Medical Center, Durham, North Carolina NORTON NELSON, Institute of Environmental Medicine, New York University Medical Center, New York, New York Board Staff DEVRA LEE DAVIS, Executive Director JACQUELINE PRINCE, Staff Associate
ACKNOWLEDGMENTS vi Acknowledgments Many persons provided the Committee and staff with helpful information, suggestions, and the benefits of their experience during preparation of this report. We wish especially to express our gratitude for contributions made by Edward Baker, Roger Detels, Jack Hackney, Carl Hayes, Kaye Kilburn, Brian Leaderer, Samuel Marcus, Jean McRae, Rene Mendes, Paul Morrow, Marvin Schneiderman, Kirk Smith, and Warren Muir. We also wish to thank Barbara Mandula, who helped organize the project in its early stages and contributed substantially to its completion; Danny Kao and Christopher Wendel, who also helped finish it; Edna Paulson and Victor Miller, of the Toxicology Information Center, who provided continual access to the literature; and Gunther Craun, of the Environmental Protection Agency (EPA), our project officer. Devra Lee Davis, Executive Director of the Board on Toxicology and Environmental Health Hazards, provided valuable assistance in review throughout this project, and Alvin G. Lazen, Executive Director of the Commission on Life Sciences, offered much helpful advice. Without the support of Bernard Goldstein and Roger Cortesi of EPA, the project would not have been possible. Without the editorial work of Norman Grossblatt, it would have been a great deal more difficult to read about; he edited the entire report with the utmost degree of efficiency and professional judgment. Finally, the extraordinary skill and unselfish dedication of James Lanear and Mary Ellen Scheckenbach were evident to all who witnessed or participated.
PREFACE vii Preface The Committee on the Epidemiology of Air Pollutants dealt with a difficult charge under severe time constraints. That it completed its task well and on time is a credit to both its members and its dedicated and outstanding National Research Council scientific staff colleagues. Dr. Peter Gann in particular assumed major responsibility for coordinating, translating, and negotiating ideas, opinions, and insights among and between Committee members, consultants, and responsible NRC executives. The Committee's report is about epidemiology, but is not written for epidemiologists. It is a written answer to a specific charge from EPA administrators. In the Committee's view, the report to the EPA administrators is likely to be of interest to a much wider audience of federal and state air pollution control program directors, as well as to a variety of scientists concerned with air and industrial pollution questions. These scientists will mostly be in other scientific disciplines and have a need either to work with epidemiologists or to use epidemiologic strategies. The Committee members met and shared a wide variety of opinions about the match between pertinent air pollution research questions and current epidemiologic concepts and strategies. These individuals had been chosen for their diversity of expertise, experience, and opinions, and they devised a work plan that would use this diversity to full advantage. The Committee established a common base of state-of-the-art knowledge through the circulation and discussion of background papers prepared by its own experts. It then implemented its functional plan that depended upon meetings of small ad hoc working groups of members. These interdisciplinary working groups developed conceptual and operational approaches to assigned segments of the work at hand. The work was carried out in three phases, which moved from the most general to the most specific subject matter and from development of consensus to the preparation of the first drafts of chapters of the report. The composition and leadership of the groups were deliberately changed as work progressed. Every effort was made to concentrate attention on critical issues and ideas that had not been fully explored or reviewed in the recent literature and to avoid either discussing or writing about subjects for which good recent reviews were available. Some of the Committee's working concepts and guidelines mentioned in the report itself are worth highlighting here. It concentrated on long-term respiratory morbidity in relation to ambient air pollution. This was an expedient choice based on past and present research priorities and without reference to any changes in the relative importance of short-term respiratory effects and short- and long-term effects in other organ systems as smoking habits change. It concerned itself more
PREFACE viii with public than with personal health and more with morbidity than with mortality. This was another decision taken to expedite and focus the Committee's effort. It does not imply that clinical observations and mortality data should be disregarded by future investigators. The full Committee agreed upon the most important research questions in air pollution and used them to test the practicality of its conclusions and recommendations. Some of this work is included in the report to illustrate ways in which epidemiologic methods can be applied to current air pollution research questions. The Committee's conceptual approach is a little different from the usual. It used a working concept of ambient air as âthe air breathed in 24 hoursâ and ambient pollution as âthe pollutants in breathed air.â In its thinking, it did not try to separate that part of the air breathed in and out each day by an average man or woman that comes from indoor, outdoor, or occupational sources. This definition accepted a very heterogeneous exposure to pollutants, pollutant mixtures, and their concentrations. The synergistic as well as additive effects of mixtures of pollutants were an important facet of this heterogeneity. Another working concept made explicit by the Committee is that irritants like cigarette smoke reach the lungs in the medium of breathed air, which can potentiate or reduce their biological impact. A public health perspective is maintained throughout the report with reference to attributable risk and to effects that are harder to distinguish among individuals than among populations. Finally, the Committee conducted its own deliberations about research strategies and methods keeping in mind total sources of bias in any epidemiologic air pollution research project. The report itself was prepared and edited by Committee members before it was sent to consultants and reviewers. The distributed responsibilities for writing put an additional burden on the entire staff of the Committee. The report could not have been completed in time without their uniform and continual responsiveness and patience. Maureen Henderson Chairman Committee on the Epidemiology of Air Pollutants
CONTENTS ix Contents Executive Summary 1 1 Introduction 21 2 Assessment of Health Effects 37 3 Exposure Assessment 89 4 Concepts and Strategies in Planning Epidemiologic Stud- 127 ies on Air Pollution 5 The Application of Epidemiology to Selected Research 165 Questions 6 Conclusions and Recommendations 191 Appendix A Morbidity and Mortality From Respiratory Disease in the 202 United States Appendix B National Ambient Air Quality Standards 204 Appendix C Pitfalls in Design, Analysis, and Interpretation 205
CONTENTS x
