Will the circle be unbroken: a history of the U.S. National Ambient Air Quality Standards.

INTRODUCTION

Following is the 2007 A & WMA Critical Review (1-3) Discussion: "Will the Circle Be Unbroken: A History of the U.S. National Ambient Air Quality Standards." In the review, John D. Bachmann traces the regulatory history of U.S. air pollution from the beginning of the 20th century to the present. The review divides this progress into four segments: (1) 1900-1970, from smoke abatement to federal involvement and the establishment of air quality management (AQM) in the 1970 Clean Air Act (CAA); (2) 1971-1976, when the first National Ambient Air Quality Standards (NAAQS) were promulgated and implemented; (3) 1977-1993, which included the first NAAQS revisions, major CAA amendments, and the evolution of AQM; and (4) 1993-2006, the second and third waves of NAAQS revisions and their implementation in the context of the 1990 CAA amendments.

Invited and contributing discussants agree with, contest, and add to topics treated in the review. Each discussion is self-contained, and joint authorship of this article does not imply that a discussant subscribes to the opinions expressed by others. A discussant's commentary does not necessarily reflect the position of his or her respective organization. In particular, Mobley's comments have not been reviewed by the U.S. Environmental Protection Agency (EPA) and do not reflect official positions or policy of the agency.

This Critical Review Discussion was compiled from written submissions and presentation transcripts that were edited for conciseness, to minimize redundancy, and to provide supporting and instructional citations. Substantial deviations from the intent of a discussant are unintentional and can be addressed in a follow-up letter to the Journal. The invited discussants are as follows:

* Mr. Howard J. Feldman is director of regulatory and scientific affairs for the American Petroleum Institute (API). He is charged with developing and promoting credible, cost-effective policies, strategies, positions, standards, and practices; supporting federal and state regulatory and legislative initiatives; and developing and managing relevant, scientifically sound research. He has served as the co-chairman of the NARSTO Executive Steering Committee, which addresses the management of regional and urban air quality in North America.

* Ms. Janice E. Nolen is assistant vice president of national policy and advocacy for the American Lung Association. She directs the development of policy positions on lung disease, air quality, and tobacco control for the nationwide organization and represents the Lung Association with its partner organizations and with federal agencies in policy and regulatory issues. Part of her work involves producing the Lung Association's widely read annual report on air pollution, the State of the Air. She serves on EPA's CAA Advisory Committee (CAAAC).

* Dr. Barry Wallerstein is executive officer at the South Coast Air Quality Management District (SCAQMD). He has over 20 yr of experience in urban planning and environmental studies, with an emphasis in air pollution control and public policy development. He has served SCAQMD in various positions since 1984 and was appointed Acting Executive Officer in August 1997. The Governing Board unanimously elevated him to executive officer in November 1998. He has also worked as an environmental control administrator for Northrop, and was a member of the rule development staff in the Mobile Source Division of the California Air Resources Board (CARB).

* Dr. John G. Watson is a research professor in the Division of Atmospheric Sciences at the Desert Research Institute, a part of the Nevada System of Higher Education. He has more than 30 yr of experience in conducting decision-making air quality studies to determine major contributions to excessive concentrations and the effects of emission reduction strategies. He is currently chair of a National Academy of Engineering committee on "Energy and Air Quality Futures in Urban China and the United States."

The contributing discussants are as follows:

* Dr. George M. Hidy is primary of Envair/Aerochem. He has served as an advisor to the electric utility industry and government on air quality issues, and has authored reviews on airborne particles and atmospheric chemistry. His research interests include atmospheric aerosols and their environmental consequences, including health effects. He is Co-Editor of this Journal.

* Dr. Paul J. Lioy is a professor in the Department of Environmental and Occupational Medicine, Robert Wood Johnson Medical School, (RWJMS) University of Medicine and Dentistry, New Jersey (UMDNJ), and Deputy Director of Government Relations and Director of the Exposure Science Division of the Environmental and Occupational Health Sciences Institute, RWJMS-UMDNJ and Rutgers University. His research covers environmental health, exposure science, and air pollution problems. He is a member of the EPA Science Advisory Board, and has served as a member or chair of National Research Council (NRC) committees.

* Dr. Herbert McKee is an environmental consultant and 52-yr member of A & WMA. He served approximately 40% of that time as a state or local regulatory official. His experience includes many research projects on ozone ([O.sub.3]) measurement and control, among other topics.

* Mr. David Mobley, P.E., is associate director of the Atmospheric Modeling Division of the EPA's Office of Research and Development. He served as coordinator of the NARSTO Emission Inventory Assessment.

* Mr. Keith Baugues, P.E., is technical leader of air services for KERAMIDA Environmental and is past chair of A & WMA's AM-1 Committee on Emission Factors and Inventories.

The musical contributions from Mr. Bachmann and Dr. Watson presented at A & WMA's 100th anniversary meeting in Pittsburgh, PA, will be available on the A & WMA Web site: www.awma.org.

INVITED COMMENTS FROM MR. HOWARD J. FELDMAN

The stated goal of the 2007 A & WMA Critical Review1 is to summarize AQM since 1900, with an emphasis on the U.S. NAAQS. The review presents lessons learned, key issues, and challenges for future AQM, as well as possible improvements and alternative approaches for the future. It provides an excellent history of the NAAQS, and it will become one of the fundamental resources on this subject for air quality experts and others. The review could be enhanced with additional attention to the lessons learned and possible new AQM approaches.

The review highlights three key NAAQS issues that are still part of today's decision-making paradigm: (1) establishing protective thresholds for criteria pollutants, (2) setting NAAQS with an adequate margin of safety, and (3) protecting the public health and welfare from any known or anticipated adverse effect.

In 1979, the EPA Administrator stated, "the Administrator recognizes, however, that controlling [O.sub.3] to very low levels is a task that will have significant impact on economic and social activity. It is thus important that the standard not be any more stringent than protection of health demands." (4) The current science has led experts to question whether thresholds exist, whether there is an adequate margin of safety, and how "public health" and "adverse effects" are defined. The review could have more critically addressed how these issues should affect the [O.sub.3] standard (5) to be promulgated in 2008 and future NAAQS reviews.

To enhance current and future AQM, several issues need more attention and analysis than given in the review. These include: (1) how AQM has been executed in the last 30 yr and how it will be conducted in the future, (2) the quality of emission inventories, (3) monitoring technology and human exposure, (4) background levels, and (5) accountability.

With respect to AQM execution, state implementation plans (SIPs) have not always achieved the intended air quality gains; in many cases, SIP control measures failed to achieve the predicted attainment with the NAAQS. (6) SIPs did not show attainment because photochemical models were not "data constrained"--modelers could always replicate [O.sub.3] to within [+ or -]30% of monitored values.

In some cases, attainment dates extend well beyond the NAAQS review cycle. The ramifications are that a state could design an attainment program for a given NAAQS, later to have that NAAQS modified or vacated. This could lead to the non-optimum use of planning and control resources and could further delay NAAQS attainment. For example, a state could design an [O.sub.3] attainment strategy focused on volatile organic compound (VOC) emission reductions, only to be later confronted with a revised [O.sub.3] standard for which oxides of nitrogen (N[O.sub.x]) reductions would have been preferable.

Emission inventories, anthropogenic and biogenic, have been flawed, (7) despite major advances over the last 30 yr. Higher than estimated in-use vehicle emissions were detected through two different approaches: (1) the 1987 Southern California Air Quality Study (SCAQS) tunnel experiment revealed that measured carbon monoxide (CO) and VOC emission rates were three and four times higher, respectively, than estimated by available emission models (8); and (2) on-road vehicle emission monitors revealed that most vehicles were low emitters, with a small fraction producing a large fraction of light-duty vehicle emissions. (9) As described in greater detail below, NARSTO has completed a comprehensive emission inventory assessment. (10) The highest priority should be to reduce emission uncertainties associated with poorly characterized sources.