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The Intended Roles of NARSTO and Its Ozone Assessment Report

WHY NARSTO?

The U.S. Clean Air Act (CAA) Amendments of 1970 mandated National Ambient Air Quality Standards (NAAQS) for a range of air pollutants, including photochemical oxidants, a class of chemicals formed by reactions in the atmosphere. In 1978, the NAAQS for photochemical oxidants was narrowed to target ozone specifically, and was relaxed to allow 50% higher ambient concentrations. Between 1982 and 1990, the number of urban areas failing to meet the ozone NAAQS never dropped below 63, and in 1990 it stood at 98 (NRC 1991). Two decades after the initial NAAQS, it was clear that many urban areas would not be able to attain the national standards despite strong efforts.

Anticipating the need to reauthorize the CAA, the U.S. Office of Technology Assessment (OTA) issued in 1989 a major study of the effectiveness of actions taken under the CAA and a discussion of possible alternative strategies. Entitled Catching Our Breath—Next Steps for Reducing Urban Ozone (OTA 1989), this report concluded that “obviously, local controls on VOCs [volatile organic compounds] cannot solve the Nation's ozone problem.” After reviewing efforts in the 1970s and 1980s to control urban ozone by VOC emissions reductions, the OTA report discussed the interaction of VOC and oxides of nitrogen (NOx) as ozone precursors, the role of rural and regional ozone enhancements, and the possibilities of NOx controls and more aggressive VOC controls. A range of potential policy options for further precursor controls were presented. The OTA report summary went on to opine, “New control methods will be needed, but looking beyond the traditional controls raises challenging new technical and political issues.”

Following the OTA report, the U.S. Congress requested a study of the urban ozone problem by the National Research Council (NRC) and a formal report by U.S. EPA on the same topic. NRC (1991) presented a detailed analysis of the atmospheric chemistry and meteorology of tropospheric ozone formation. It highlighted the weaknesses in the U.S. strategy of relying on VOC reductions alone to attain ozone standards. The NRC report was very critical of the quality of U.S. EPA's emissions inventories for both NOx and VOCs, the lack of ambient VOC monitoring data to determine if VOC control strategies were actually reducing urban VOC concentrations, and the deficiencies in photochemical air-quality models used to design attainment strategies. It also strongly recommended a focused and sustained urban and regional tropospheric ozone research program designed to develop atmospheric-process knowledge, to improve emissions inventories, and to enhance the research and monitoring tools and strategies required for developing better attainment strategies to meet air-quality targets.



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REVIEW OF THE NARSTO DRAFT REPORT: AN ASSESSMENT OF TROPOSPHERIC OZONE POLLUTION–A NORTH AMERICAN PERSPECTIVE 2 The Intended Roles of NARSTO and Its Ozone Assessment Report WHY NARSTO? The U.S. Clean Air Act (CAA) Amendments of 1970 mandated National Ambient Air Quality Standards (NAAQS) for a range of air pollutants, including photochemical oxidants, a class of chemicals formed by reactions in the atmosphere. In 1978, the NAAQS for photochemical oxidants was narrowed to target ozone specifically, and was relaxed to allow 50% higher ambient concentrations. Between 1982 and 1990, the number of urban areas failing to meet the ozone NAAQS never dropped below 63, and in 1990 it stood at 98 (NRC 1991). Two decades after the initial NAAQS, it was clear that many urban areas would not be able to attain the national standards despite strong efforts. Anticipating the need to reauthorize the CAA, the U.S. Office of Technology Assessment (OTA) issued in 1989 a major study of the effectiveness of actions taken under the CAA and a discussion of possible alternative strategies. Entitled Catching Our Breath—Next Steps for Reducing Urban Ozone (OTA 1989), this report concluded that “obviously, local controls on VOCs [volatile organic compounds] cannot solve the Nation's ozone problem.” After reviewing efforts in the 1970s and 1980s to control urban ozone by VOC emissions reductions, the OTA report discussed the interaction of VOC and oxides of nitrogen (NOx) as ozone precursors, the role of rural and regional ozone enhancements, and the possibilities of NOx controls and more aggressive VOC controls. A range of potential policy options for further precursor controls were presented. The OTA report summary went on to opine, “New control methods will be needed, but looking beyond the traditional controls raises challenging new technical and political issues.” Following the OTA report, the U.S. Congress requested a study of the urban ozone problem by the National Research Council (NRC) and a formal report by U.S. EPA on the same topic. NRC (1991) presented a detailed analysis of the atmospheric chemistry and meteorology of tropospheric ozone formation. It highlighted the weaknesses in the U.S. strategy of relying on VOC reductions alone to attain ozone standards. The NRC report was very critical of the quality of U.S. EPA's emissions inventories for both NOx and VOCs, the lack of ambient VOC monitoring data to determine if VOC control strategies were actually reducing urban VOC concentrations, and the deficiencies in photochemical air-quality models used to design attainment strategies. It also strongly recommended a focused and sustained urban and regional tropospheric ozone research program designed to develop atmospheric-process knowledge, to improve emissions inventories, and to enhance the research and monitoring tools and strategies required for developing better attainment strategies to meet air-quality targets.

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REVIEW OF THE NARSTO DRAFT REPORT: AN ASSESSMENT OF TROPOSPHERIC OZONE POLLUTION–A NORTH AMERICAN PERSPECTIVE Following the 1991 NRC report, U.S. EPA issued its report to Congress. The U.S. EPA report accepted many of the points made by the 1991 NRC report, including the need for a coordinated national research program on tropospheric ozone (EPA 1993). In June 1994, U.S. EPA, the U.S. National Oceanic and Atmospheric Administration, and the Electric Power Research Institute hosted over 120 atmospheric scientists from governmental agencies, industry, universities, and private-sector research organizations in Canada, Mexico, and the United States to discuss and design a North American Research Strategy for Tropospheric Ozone (NARSTO). The research strategy designed by this group was extensive and comprehensive (NARSTO 1994). It corresponded closely to the research emphases recommended by NRC (1991). This initial NARSTO strategy document was later supported with a more-detailed NARSTO Strategic Execution Plan (NARSTO 1997). However, although governmental and private-sector funding have allowed some important, large-scale field studies to proceed (e.g., NARSTO 1995; Chameides and Cowling 1995), most of the NARSTO research plan has not yet been implemented. NARSTO MISSION The primary mission of NARSTO is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric ozone behavior, with the central programmatic goal of determining workable, efficient, and effective strategies for local and regional ozone management. In accomplishing this goal, NARSTO is charged with establishing and maintaining effective communication channels between its scientific effort and its client community of planners, decision-makers, stakeholders, and strategic analysts. It is also charged with providing a cross-organization planning process to determine the most-effective strategies for scientific investigation. NARSTO coordinates the allocation of financial resources to implement those strategies, and monitors progress of its effort toward fulfillment of its programmatic goal. NARSTO sought to focus its implementation of this mission by adopting sets of scientific and policy questions in its Strategic Execution Plan to direct its research efforts (NARSTO 1997). These questions are reproduced in Appendix C of this report. The questions, taken one by one, are inherently interesting, and their resolution would advance knowledge about the ozone issue. However, it is not clear how well these questions interact to frame a coherent program that would result in a fundamental strategy for a path forward in meeting ozone-control goals. Because the committee was not asked to evaluate the Strategic Execution Plan itself in this report, the committee did not review the plan in detail. The Strategic Execution Plan provided for a major assessment of the current understanding of tropospheric ozone, the NARSTO assessment document, which is the focus of the committee's attention. THE ROLE OF THE NARSTO ASSESSMENT DOCUMENT The NARSTO assessment document was assigned as the first major synthesis report to be undertaken by NARSTO. It is intended to incorporate advances in scientific understanding developed after the previous reports (already mentioned) and through research undertaken under NARSTO auspices. The document's intended audience is the policy-makers charged with implementing workable, effective control strategies in North America. The audience is intended to include the scientific community with the purpose of providing a broadened and holistic understanding of the ambient ozone situation. The 24 critical review papers commissioned by NARSTO (Appendix B) are intended to provide a major scientific basis for the document. In summary, the NARSTO assessment document is intended to “compile and evaluate the state of

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REVIEW OF THE NARSTO DRAFT REPORT: AN ASSESSMENT OF TROPOSPHERIC OZONE POLLUTION–A NORTH AMERICAN PERSPECTIVE knowledge of tropospheric ozone and related chemical and physical processes” (NARSTO 1997). Beyond this, it is intended to provide “wisdom” to those charged with administrating ozone research and management programs. The purpose of the NARSTO assessment document is summarized in four objectives dictated by the NARSTO Strategic Execution Plan (NARSTO 1997): Provide a synthesis and evaluation of policy-relevant scientific findings, methods, and recommendations that are timely and useful for regulatory initiatives and mid-course corrections Provide guidance for setting NARSTO priorities for long-term research that will extend beyond the 2- to 3-year time frame Examine alternatives to current technical approaches for achieving ozone compliance Ensure that information on ozone-precursor chemistry is well integrated with related pollutant issues, such as fine particulate matter, visibility impairment, and acid deposition. En route to meeting those objectives, the authors of the NARSTO assessment document were given specific scientific and policy questions that they were to address. These are reproduced in Appendix D of this report. The following chapter reviews the NARSTO assessment document and identifies some of its successes and shortcomings in meeting the daunting challenges presented to its authors.