Haze in the Grand Canyon: An Evaluation of the Winter Haze Intensive Tracer Experiment Committee on Haze in National Parks and Wilderness Areas National Academy Press i Haze in the Grand Canyon An Evaluation of the Winter Haze Intensive Tracer Experiment Committee on Haze in National Parks and Wilderness Areas Board on Environmental Studies and Toxicology Board on Atmospheric Sciences and Climate Commission on Geosciences, Environment, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1990 About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. ii NATIONAL ACADEMY PRESS 2101 Constitution Ave., N.W. Washington, D.C. 20418 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 competencies 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 Sci- ences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, non-profit, self-perpetuating society of distin- guished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the fed- eral government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sci- ences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy mat- ters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal govern- ment and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine. The National Research Council was organized 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 advising the federal government. Functioning in accordance with general poli- cies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is adminis- tered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. This study was supported by contract numbers 14-01-0001-89-C-39 between the National Academy of Sciences and the Department of the Interior, DE-FG01-90FE62072 from the Depart- ment of Energy, (Purchase Order Number) 0D1447NANT from the Environmental Protection Agency, and VN-08016CAS from the Arizona Salt River Project. Library of Congress Catalog Card No. 90-62765 International Standard Book Number 0-309-04341-7 S226 Additional copies of this report are available from the National Academy Press ,2101 Constitution Avenue, N.W., Washington, D.C. 20418 Cover art by Terry Parmelee. Printed in the United States of America About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. iii Committee on Haze in National Parks and Wilderness Areas ROBERT A. DUCE, Chairman, University of Rhode Island, Narragansett JACK G. CALVERT, Vice Chairman, National Center for Atmospheric Research, Boulder, CO GLEN R. CASS, California Institute of Technology, Pasadena ROBERT J. CHARLSON, University of Washington, Seattle JOHN E. CORE, Oregon Department of Environmental Quality, Portland WILLIAM H. ELDER, Tennessee Valley Authority (retired), Muscle Shoals, AL PETER H. MCMURRY, University of Minnesota, Minneapolis PAULETTE B. MIDDLETON, State University of New York, Albany CRAIG N. OREN, Rutgers (State University of New Jersey) School of Law, Camden JOSEPH M. PROSPERO, University of Miami, Miami PERRY J. SAMSON, University of Michigan, Ann Arbor IAN M. TORRENS, Electric Power Research Institute, Palo Alto JOHN TRIJONIS, Santa Fe Research Corp., Bloomington, MN WARREN H. WHITE, Washington University, St. Louis F. SHERWOOD ROWLAND, Liaison Member for the Board on Environmental Studies and Toxicology, University of California, Irvine Project Staff ROBERT B. SMYTHE, Program Director KATHLEEN DANIEL, Project Director RAYMOND A. WASSEL, Staff Officer LEE R. PAULSON, Editor RUTH E. CROSSGROVE, Copy Editor ANNE M. SPRAGUE, Information Specialist SANDRA W. FITZPATRICK, Administrative Assistant FELITA S. BUCKNER, Project Assistant BOYCE N. AGNEW, Project Assistant About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. iv Board on Atmospheric Sciences and Climate JOHN A. DUTTON, Chairman, Pennsylvania State University, University Park JON F. BARTHOLIC, Michigan State University, East Lansing RAFAEL L. BRAS, Massachusetts Institute of Technology, Cambridge MOUSTAFA T. CHAHINE, California Institute of Technology, Pasadena ROBERT A. DUCE, University of Rhode Island, Narragansett MICHAEL H. GLANTZ, National Center for Atmospheric Research, Boulder THOMAS E. GRAEDEL, AT&T Bell Laboratories, Murray Hill, NJ DAVID D. HOUGHTON, University of Wisconsin, Madison RICHARD G. JOHNSON, Los Altos, CA EUGENIA KALNAY, National Meteorological Center, Washington, D.C. SYUKURO MANABE, Princeton University, Princeton GERALD R. NORTH, Texas A&M University, College Station JAMES J. O'BRIEN, Florida State University, Tallahassee Ex-Officio Members ROBERT DICKINSON, National Center for Atmospheric Research, Boulder ROBERT E. SIEVERS, University of Colorado, Boulder PETER S. RAY, Florida State University, Tallahassee DONALD J. WILLIAMS, John Hopkins University, Laurel, MD About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. v Board on Environmental Studies and Toxicology GILBERT S. OMENN (Chairman), University of Washington, Seattle FREDERICK R. ANDERSON, Washington School of Law, American University JOHN C. BAILAR, III, McGill University School of Medicine, Montreal LAWRENCE W. BARNTHOUSE, Oak Ridge National Laboratory, Oak Ridge GARRY D. BREWER, Yale University, New Haven JOANNA BURGER, Nelson Laboratory, Rutgers University, Piscataway, NJ YORAM COHEN, University of California, Los Angeles JOHN L. EMMERSON, Lilly Research Laboratories, Greenfield, IN ROBERT L. HARNESS, Monsanto Agricultural Company, St. Louis ALFRED G. KNUDSON, Fox Chase Cancer Center, Philadelphia GENE E. LIKENS, The New York Botanical Garden, Millbrook PAUL J. LIOY, UMDNJ-Robert Wood Johnson Medical School, Piscataway JANE LUBCHENCO, Oregon State University, Corvallis DONALD MATTISON, University of Pittsburgh, Pittsburgh NATHANIEL REED, Hobe Sound, FL F. SHERWOOD ROWLAND, University of California, Irvine MILTON RUSSELL, University of Tennessee, Knoxville MARGARET M. SEMINARIO,AFL/CIO, Washington, DC I. GLENN SIPES, University of Arizona, Tucson WALTER J. WEBER, JR., University of Michigan, Ann Arbor Staff JAMES J. REISA, Director DAVID J. POLICANSKY, Program Director for Natural Resources and Applied Ecology ROBERT B. SMYTHE, Program Director for Exposure Assessment and Risk Reduction RICHARD D. THOMAS, Program Director for Human Toxicology and Risk Assessment LEE R. PAULSON, Manager, Toxicology Information Center About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. vi Commission on Geosciences, Environment, and Resources* M. GORDON WOLMAN (Chairman), The Johns Hopkins University ROBERT C. BEARDSLEY, Woods Hole Oceanographic Institution B. CLARK BURCHFIEL, Massachusetts Institute of Technology, Cambridge RALPH J. CICERONE University of California, Irvine PETER S. EAGLESON, Massachusetts Institute of Technology, Cambridge GENE E. LIKENS, New York Botanical Gardens, Millbrook SCOTT M. MATHESON, Parsons, Behle & Latimer, Salt Lake City JACK E. OLIVER, Cornell University, Ithaca PHILIP A. PALMER, E.I. du Pont de Nemours & Co., Newark, DE FRANK L. PARKER, Vanderbilt University, Nashville DUNCAN T. PATTEN, Arizona State University, Tempe MAXINE L. SAVTTZ, Allied Signal Aerospace, Torrance, CA LARRY L. SMARR, University of Illinois at Urbana-Champaign, Champaign STEVEN M. STANLEY, Case Western Reserve University, Cleveland SIR CRISPIN TICKELL, United Kingdom Mission to the United Nations KARL K. TUREKIAN, Yale University, New Haven IRVIN L. WHITE, New York State Energy Research and Development Authority, Albany JAMES H. ZUMBERGE, University of Southern California, Los Angeles Staff STEPHEN RATTIEN, Executive Director STEPHEN D. PARKER, Associate Executive Director JANICE E. GREENE, Assistant Executive Director JEANETTE A. SPOON, Financial Officer * This study was begun under the Commission on Physical Sciences, Mathematics, and Resources, whose members are listed in Appendix 4, and completed under the successor Commission on Geosciences, Environment, and Resources. About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. PREFACE vii Preface Many delightful experiences can be enjoyed in our nation's numerous national parks and wilderness areas, but among the finest are the beautiful views of nature found in these locations. Particularly spectacular are the often distant and majestic scenes of mountains, deserts, plains, and ocean. Our concern for maintaining the clarity of views in these areas is reflected in the Clean Air Act, which specifically addresses the protection of visibility in our national parks and wilderness areas. Early in 1990, the National Research Council (NRC) established the Committee on Haze in National Parks and Wilderness Areas to address issues related to visibility degradation in these protected regions. In particular, the committee was asked to consider the relative importance of human-derived and natural emissions that contribute to visibility reduction in these locations and to evaluate possible source-control approaches. As part of its charge, the committee was also asked to evaluate a recent scientific study by the National Park Service (NPS) of visibility degradation and its causes in one of our most beautiful national parks, Grand Canyon. This publication is the committee's evaluation of the NPS report on the Winter Haze Intensive Tracer Experiment (WHITEX) and its conclusion that the Navajo Generating Station (NGS) contributed to wintertime visibility impairment in Grand Canyon National Park during the study. The committee's task was not an easy one. Source apportionment is a rather inexact but very complex component of the atmospheric sciences. New techniques and approaches are constantly being designed and tested, and personal judgment and experience often play significant roles in evaluation processes. However, I have never worked with a committee more dedicated to the development of a fair, objective, and honest evaluation of what has become a controversial issue. Everyone involved in this NRC project, including the sponsoring organizations, cooperated in every way possible. The committee met at Grand Canyon National Park from March 28-31, 1990. We were provided with extensive written and oral information by feder About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. Page breaks are true to the original; line lengths, word breaks, heading styles, and other typesetting-specific formatting, however, cannot be retained, and some typographic errors may have been accidentally inserted. Please use the print version of this publication as the authoritative version for attribution. PREFACE viii al personnel and other project sponsors, including the National Park Service, the Bureau of Reclamation, the Department of the Interior's Office of Environmental Quality, the Department of Energy, the Environmental Protection Agency, the Forest Service, and the Arizona Salt River Project (operators of NGS) and their consultants. We were also given an extensive tour of the NGS and of the atmospheric monitoring station at Hopi Point in Grand Canyon National Park. After this meeting, the federal liaison group—representing the sponsoring agencies—and the Arizona Salt River Project continued to provide the committee with information promptly whenever it was requested. This was greatly appreciated. In addition to the committee's formal meetings, committee members and NRC staff spent many hours in conference calls and in individual conversations. The committee's heartfelt thanks must go to the NRC staff who devoted themselves so thoroughly to this report. Dr. James J. Reisa, the director of the Board on Environmental Studies and Toxicology, and Dr. Robert Smythe, the program director, provided us with guidance, perspective, and oversight. The project director, Kathleen J. Daniel, worked closely with committee members through all phases of the report preparation. Her enthusiasm, knowledge of the field, sense of humor, commitment to a quality report, and true concern about the issues being addressed played a major role in the committee's efforts, and in particular, in our development of a consensus on this controversial issue. We also thank staff member Raymond Wassel, who contributed significantly to the committee's efforts, and Felita Buckner, Boyce Agnew, and Sandi Fitzpatrick, who worked closely and effectively with the committee throughout report preparation and production. Finally, Lee Paulson took our often-tangled prose and provided clear renditions and editorial revisions. The committee hopes this report will provide useful suggestions and guidance as the nation continues efforts to protect and preserve the natural visibility in our national parks and wilderness areas for ourselves and future generations. ROBERT A. DUCE CHAIRMAN OCTOBER 3, 1990 About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. 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CONTENTS ix Contents Executive Summary 1 Background 9 The NRC Committee Study 15 The Committee, Its Charge, and Its Approach, 15 The Committees Specific Interpretation of Its Charge, 16 Evaluation of WHITEX 16 WHITEX Overview, 16 WHITEX Source-Atribution Models, 18 Critical Aspects of WHITEX Techniques and Design, 19 Qualitative Assessment, 19 Quantitative Assessment, 23 Limitations of the WHITEX Study, 24 Weaknesses in the Data Base, 24 Departures from Statistical Assumptions, 25 Formulation of Statistical Models, 26 Simplifications in the DMB Model, 31 Potential Covariance of NGS and Other Source Con- 32 tributions, Estimates of the Range of Possible Impacts of NGS 33 Emissions at Hopi Point, The Committee's Conclusions in Perspective 37 Conclusions 37 References 39 About this PDF file: This new digital representation of the original work has been recomposed from XML files created from the original paper book, not from the original typesetting files. 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