7
Conclusion
The importance of enhancing the understanding of the relationship between airborne particulate matter (PM) and health has led the nation to embark on a multiyear, multidisciplinary research program designed to inform decisions on the PM NAAQS and to evaluate the effectiveness of source control strategies. During its tenure, the committee has had the opportunity to propose a research agenda, monitor its implementation, and gauge initial progress in reducing key scientific uncertainties. This 5-year experience has provided an opportunity to make observations concerning the process of initiating and subsequently managing a large multidisciplinary research program. Through this process, the committee identified some strengths and weaknesses of research and management approaches. The committee has also seen some of the initially recommended studies reach publication and then enter into EPA’s process of NAAQS review.
Overall progress to date on several of the committee’s priority research topics is encouraging and demonstrates that some of the key uncertainties can be addressed quickly by using targeted research initiatives, as in the example of research on outdoor concentrations versus actual human exposure (topic 1). It is not surprising that much research remains to be done from the committee’s original research agenda, as detailed in Chapters 3 and 4. That conclusion is especially true for the related topics of characterization of emission sources (topic 3) and air quality model development and testing (topic 4), which are critical to informing future decisions, as well as assessment of hazardous PM components (topic 5).
Beyond continuing to seek the answers to these specific questions, the committee has identified seven important scientific challenges that need to be addressed as implementation of the committee’s research portfolio proceeds:
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Completing the PM emissions inventory and developing and testing air quality models for the implementation of current and possible future PM NAAQS.
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Developing a systematic program to assess the comparative toxicity of different components of the PM mixture and of the mixture itself.
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Planning and implementing new studies on the effects of long-term exposure.
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Improving the relevance of toxicological approaches.
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Enhancing the ability of the air quality monitoring system to track progress and serve as an element for estimating exposure for future health research.
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Moving beyond PM to a multipollutant approach to improve air quality overall in a health-relevant manner.
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Integrating disciplines.
Some progress has been made in addressing these challenges (for example, the implementation of the nationwide speciation monitoring network), but these seven issues need careful attention as the PM research program continues. By addressing these issues directly, it is the committee’s judgment that the pace of scientific gain should be quickened, and the quality of research evidence strengthened.
These issues also pose important challenges to the management of science. To be able to address them effectively, Chapter 6 has identified a series of steps that must be taken to effectively manage this complex scientific enterprise, which can be grouped into three broad categories:
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An even higher level of sustained integration and interaction both among the scientific disciplines and among the full range of public and private research funding organizations will be needed to complete the research portfolio.
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Much stronger tools will be needed to compile and synthesize the large amounts of new information being developed in this research program.
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Perhaps most important, sustained and substantially enhanced management of this program by EPA, accompanied by a continuing mechanism for independent review and oversight of the program, will be the only way to ensure that the investment in the research is being made. EPA has taken steps toward better management, but recent transitions in the management of that effort and a substantial need for new management systems and
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administrative mechanisms for supporting research, especially on the topic of assessment of hazardous PM components, suggest that EPA will need to enhance its efforts. Equally important will be the development of some form of a successor to this committee to provide continued monitoring and guidance to the efforts of EPA and others.
Much has been learned since 1998 research investment, and the evidence gained by the investment is already being used in the decisions that will continue to be made even with the uncertainties. Much is still to be learned. A failure to invest in advancing the understanding of the effects of PM and air pollution on health risks would result, in general, in not taking full advantage of the substantial research investment to date and limiting the nation’s ability to make evidence-based health policy and air quality regulatory choices in the future. Alternatively, continued enhancement of the air pollution and health research effort will undoubtedly yield substantial benefits for years to come. It is clearly the latter choice that offers the most promise to the nation in its effort to improve air quality and public health.