The Way Forward
The expanded particulate matter (PM) research program recommended by the present committee was prompted by a widespread scientific and policy concerns that current PM exposures in the United States can cause adverse public health effects. The PM National Ambient Air Quality Standards (NAAQS) promulgated in 1997 were based on the scientific evidence of public health risks from inhaling particles. At the same time, gaps in the available evidence raised questions concerning the scientific basis for the standards that needed to be addressed to strengthen the base of evidence for future PM NAAQS setting and implementation.
Beginning in 1998, with guidance from this committee, the U.S. Environmental Protection Agency (EPA), other agencies, and the scientific community initiated an expanded national effort to address high-priority research needs for PM by targeting research for key gaps in the scientific evidence. This effort was expected to require over a decade-long investment. The pace and scope of PM research have accelerated, and new research findings are available for policymakers engaged in reviewing the scientific basis for the PM NAAQS. There is increasing multidisciplinary exchange involving epidemiologists, toxicologists, exposure assessors, and atmospheric scientists on how best to integrate the work of the various disciplines. A new national monitoring system has been installed that is beginning to provide data on ambient concentrations of PM2.5 across the United States, and the sites will soon provide additional detail on particle characteristics across the country. As shown in previous chapters, the research effort is now starting to yield important dividends while raising new questions for further research. The experience to date has also provided lessons in the effective management of research.
However, important issues need to be addressed to ensure sustained
progress most notably the important scientific challenges identified in Chapter 5: developing a systematic program to assess the toxicity of different components of the PM mixture, planning and implementing new studies of the effects of long-term exposure, improving the relevance of toxicological approaches, enhancing the nation’s air quality monitoring system, and ultimately moving beyond PM to a multipollutant approach. A shift towards these objectives will require enhanced, multidisciplinary research, and although progress has been made in improving the management of PM research and the gathering and synthesis of information, significant science management challenges remain to be addressed before the goals of the research plan recommended by the committee can be reached. In this chapter, the committee provides guidance on scientific management issues that it expects to be relevant for successfully addressing key priorities for PM research in the future. These issues need to be addressed if the questions identified for continuing research in the previous chapters are to be answered successfully and in a timely fashion.
Specifically, this chapter addresses
Enhancing and sustaining research and its management at EPA and across the broader research enterprise.
Tools needed for enhancing the tracking and synthesis of the science going forward.
SUSTAINED RESEARCH MANAGEMENT
The management of any multidisciplinary, multiyear research program is challenging and requires strategic planning, leadership, commitment of a wide range of expertise, and resources. Such management is often more difficult in large public and private institutions where conflicting and changing priorities, institutional fragmentation, and administrative restrictions limit effective program implementation. Yet, sustained, creative management is essential for producing timely results that will provide answers to the key questions posed.
In its previous reports, the committee, recognized the need for this type of management and called for sustained efforts at EPA and other organizations. Management of the PM research program requires the following elements:
Broadening the scope of and setting priorities for the full range
of issues to be addressed. (The committee’s PM research portfolio was a first step toward this goal.)
Developing and implementing a plan to deploy resources—funding, intramural and extramural researchers, and multiple scientific disciplines—to address the highest priority issues.
Providing for aggregation and integrative analysis of results and data.
Tracking and iteratively reviewing progress.
Communicating issues, approaches, and progress internally and externally.
Ensuring that PM research is integrated into a broader perspective that encompasses other pollutants.
Although many agencies and organizations have been and must continue to be involved in planning and implementing PM research, EPA has appropriately applied the largest single body of resources and has played the lead role in coordinating the national research effort. The conduct of research at EPA on PM and other major pollutants is a multifaceted undertaking involving the Office of Research and Development (ORD) (intramural research at EPA and extramural research funded through its competitive programs) and the (OAQPS) Office of Air Quality Planning and Standards (air quality monitoring to characterize attainment of the NAAQS and ambient concentrations). Over the past 6 years, in response to funding from Congress and the reports of this committee, EPA took a number of steps toward implementing a multiyear, multidisciplinary PM research program. At the same time, continuing challenges remain for EPA and for the broader scientific community in accomplishing the kind of sustained, creative management that will be necessary to complete the PM research program outlined in the first two reports. The remainder of this chapter pursues the following objectives:
Briefly review progress to date at EPA.
Identify key challenges going forward for EPA.
Consider the need for broader, multiagency implementation.
Propose the development of a new scientific committee to provide continuing monitoring and advice.
Progress to Date at EPA
Science management at EPA takes place in the context of a large
agency with multiple scientific and regulatory interests and diverse funding priorities. The National Research Council, in its report Strengthening Science at the U.S. Environmental Protection Agency (NRC 2000), identified a series of challenges for improving the quality of EPA science (for example, the frequency of changes in goals, priorities, practices, structure, and funding) and called for broad improvements to those efforts, including enhanced ability to identify the most important science issues, the need for effective leadership at all levels, flexibility and accountability for agency research managers, and improved partnerships with the full range of other research entities.
Against this background, EPA applied and redeployed resources and made some progress in implementing the PM research program. Progress included establishment of a formal management structure for PM research, including a top official of EPA’s ORD and a national program director for EPA’s PM research program to manage the entire intramural and extramural research program; development and implementation of a multiyear research budget; implementing a dramatically expanded monitoring system, including the first nationwide speciated network at over 50 sites; refocusing of key requests for applications for STAR1 grants to address the priorities set forth in this committee’s portfolio; and integration of intramural and extramural efforts in some key areas, especially addressing the elements of the committee’s topic 1 (that is, personal, indoor, and outdoor exposures).
In part as a result of EPA’s efforts, the PM research program made progress in several areas described in Chapters 3 and 4. At the same time, the continuing need to address still unanswered questions and the challenge of maintaining momentum in the face of changing leadership and priorities require continued attention to enhance EPA’s management of this research undertaking. Specific suggestions to accomplish that are discussed in the next section.
Enhancing EPA Research Management
Although progress has been made in implementing the PM research program at EPA, the challenges of implementing an important air quality and public health program and placing it in the context of other pollutants over the long term call for an even greater level of emphasis on science management at EPA. Specifically, in considering the elements of success-
ful management described above, the committee identified several key challenges for EPA:
Program Management and Leadership: In response to the committee’s earlier reports, EPA for the first time appointed a top official of ORD and a national program director to plan for and coordinate the implementation of the PM research program, and in the first several years of the program, such actions helped to shape a better integrated approach. However, in the past 2 years, the position of national program director, while continuing, has been filled by several individuals on an acting basis for relatively short terms. Although the individuals involved have brought expertise and commitment to these roles, the frequent change-over will substantially undermine the long-term vision and coordination necessary to ensure the program’s success if the change-over continues over the long run. Looking forward, the committee sees the continued critical importance of sustained central management and leadership and urges the identification of longer-term appointments to this key position. The functions to be filled by the research will require the sustained appointment of individuals who can, at a minimum, provide sensitive leadership, maintain communication and coordination among agency personnel and investigators in a progressive research agenda, serve as a focal point for communication across the government and outside the government, and redirect the research agenda as needed.
Modern Management Tools: Sustained leadership from talented managers alone will not be sufficient to ensure that a complex research program, involving people from many disciplines working in multiple laboratories in government, academic, and private institutions, is managed in an efficient and effective manner. The program manager and leader and the participating scientists and support personnel need modern program and project management tools that facilitate management. Modern computer-based systems exist that can link goals, financial resources, human resources, and measures of progress together for tracking progress and making mid-course adjustments. Such an approach is of critical importance to the successful management of multiple projects oriented to achieving interrelated goals. EPA does not appear to have such a computer-based management system. When requests were made by the committee to EPA for information on project goals, allocation of resources, past expenditures, or measures of progress (manuscripts published or presentations given), the agency was always responsive, but the response each time appeared to be generated in an ad hoc fashion. Ideally, if a modern management system
were in place, such information could be generated almost instantaneously because it was already in hand. The value of such a system does not relate to responding to external requests but to facilitating the work of program researchers as they work toward common goals in a loosely affiliated network and team.
Administrative Flexibility to Deploy Resources: Any successful research program must have the ability to pursue a mix of research approaches, with investigator-initiated research to capture the fullest creativity of the scientific community balanced with more structured research strategies in key areas where systematic approaches across diverse laboratories and disciplines will be necessary. Through the STAR program, EPA has done much to improve its efforts to fund investigator-initiated research (NRC 2003) and has targeted the research requests in that program to a number of topics identified in the committee’s research portfolio. However, while EPA has moved forward on the investigator-initiated aspects of such a program, it has not balanced those efforts with the kind of fully interactive approach that is likely to be needed to accomplish the reduction of key uncertainties, especially those involving the identification of the toxicity of the different components of the PM mixture (topic 5). The imbalance is in part due to the current preference of EPA to use primarily grant and more cooperative agreement mechanisms in managing their research efforts, mechanisms that limit its ability to manage and coordinate the research more actively and to make mid-course corrections as the program evolves. Although these mechanisms are preferred for a reason—to ensure that federal agencies are not unduly directing, and perhaps stifling, scientific investigation—the complex nature of the tasks ahead for PM researchers suggests that the judicious use of more active research management strategies could be appropriate to complement the investigator-initiated approaches. EPA might do that directly or through other mechanisms.
Implementing NAAQS for PM: As discussed in previous chapters, emissions inventory development and air quality model testing and development are two particularly critical issues for the implementation of current and possible future NAAQS for PM. The committee has identified the need for faster progress in these areas, given the upcoming implementation deadlines for the PM2.5 NAAQS. EPA should provide more guidance, leadership, and coordination among the groups carrying out air quality modeling and emissions inventory work, particularly those conducting emissions characterization. Some of the needed emission characterizations will be carried out by the states, industry, and other stakeholders. Therefore, EPA will need to assume a leadership role in the development of
testing methods and source-testing performance, the coordination and compilation of results from other source-testing activities, and the updating of the source chemical composition profiles library. The committee’s second report recommended that EPA systematically characterize those sources that contribute 80% of the primary particle emissions nationally. Although EPA personnel indicated to the committee that they have ranked sources by their contribution to primary PM emissions, it is unclear whether they are using such information to set priorities for source testing. EPA will also need to ensure that the information developed through this work is quickly made available to state and local agencies as they prepare their SIPs.
EPA’s (2001) SIP attainment-demonstration guidance recognizes the uncertainties inherent in air quality simulation efforts by emphasizing a weight-of-evidence approach for showing that emission-control plans will result in sufficient air quality improvements. The attainment-demonstration guidance also emphasizes the complementary application of both source and receptor models to develop a conceptual model that can help guide the selection of appropriate controls. Despite that flexibility, the committee is concerned that the implementation of emission controls to attain the NAAQS may occur without models that have been properly evaluated and have uncertain validity. The committee previously commented that emissions tracking, air quality modeling, and ambient monitoring activities should be viewed as a set of integrated processes, each component supporting the others. Those activities will need to be given some prominence within EPA’s research program to facilitate continuous improvement in each of those areas.
A Special Effort to Address the Assessment of Hazardous PM Components: The need for enhanced science management becomes especially important when one considers the extraordinary scientific challenge posed by the assessment of the hazardous components of the PM mixture. The committee urges EPA to assume strong scientific leadership in relation to this topic. Sustained and intensive management by EPA should be substantially beyond its efforts to date, and it should have an effective mechanism for the active involvement of the full range of public and private sector research organizations. Integrated planning and augmented management structure are needed within the Agency and across the scientific community. These efforts should not be only an expanded version of “business as usual.” They will require the active and coordinated management of science in a way reminiscent of other major national scientific initiatives to develop key new technologies or to find cures and treatments
for important diseases. Although this undertaking will be costly and time consuming, the large size of the public health benefits and the potential private sector control costs will make the cost of such a research initiative small by comparison. Implementing such overarching management will benefit science and public policy substantially. But at the same time it must be implemented in a way that both brings together the scientific community in a coordinated fashion, even while ensuring that the individual innovation and creativity that different scientists can bring to the task can still contribute to the results. Maintaining this balance will be essential to the successful conduct of this important undertaking.
To implement such a program, a specific plan is needed that approaches the matrix of particle characteristics by health outcomes in an organized and tiered fashion, screening across the matrix with common approaches so that priorities can then be set for a second stage of more focused investigation. Beyond a plan, mechanisms are needed for the integrated implementation of research in a public and private partnership. An umbrella organization of the involved institutions might be needed to ensure coordination as well as efficiency in assessing hazardous PM components. Outside scientists should be involved from the outset, most likely through a steering or coordinating committee for this topic that draws on both intramural scientists, including health researchers and exposure and monitoring experts, and extramural scientists from the full range of appropriate disciplines and institutions.
Developing Future Human Resources: Accomplishing this objective requires not only talented leadership at the top but also development and renewal of trained investigators prepared to work in the required multidisciplinary arenas to meet the key scientific challenges identified in Chapter 5. Training a new generation of scientists is an essential part of any future sustained effort to explore health effects and atmospheric research in a PM or broader air pollution program. Training will need to be supported and fostered at the doctoral and post-doctoral level and within the research community of the federal government, particularly EPA. EPA had a training fellowship program that has been helpful, but budgetary support for that program has not been stable. Beyond that program, the need for such training and the mechanisms to implement it were described in valuable detail in the NRC report on strengthening science at EPA (NRC 2000).
Data Aggregation and Analysis: One key role for EPA, as a central manager of this program, is to ensure the timely collection, importation into accessible central databases, and analysis of the results and data produced by the PM research program. This role cuts across the entire
program and has been pursued in some cases, such as the multiparty efforts to collect and synthesize data on personal exposure. However, the development of such integrated approaches has been more difficult in other cases, for example, in the Supersites Program. Both the committee in its first reports and others (for example, a workshop on monitoring airborne PM [Albritton and Greenbaum 1998]) recommended that the Supersites Program be designed from the start as an integrated program that could meet the needs of multiple monitoring technology, modeling, exposure assessment, and health. Although the program has produced useful data on a site-by-site basis, and efforts have been made to compile the data in a central database, the program was not designed and implemented in an integrated and systematic manner with analysis plans built in from the beginning. This substantially limits the future usefulness of its results. To date, little funding has been made available for research efforts to analyze the wealth of data across all the sites and cooperating programs.
Beyond these specific challenges, tracking and synthesis of the scientific literature need to be substantially enhanced as the results of this PM program continue to appear (see Improved Tools for Science Tracking and Synthesis below).
Developing a Broader Multiagency Research Program
Research on PM has expanded substantially over the past decade. Support has come from a wide range of government agencies and other research funding organizations. Although EPA has been the single largest investor in such research, and its program has been a focus of the committee’s attention, the PM research community includes many other U.S. federal and state government agencies (for example, the U.S. Department of Energy [DOE], the National Institutes of Health [NIH], the National Oceanic and Atmospheric Administration [NOAA], National Science Foundation [NSF], and the California Air Resources Board [CARB]), a number of international funding organizations (for example, the European Union), several nongovernment funding organizations (for example, the Electric Power Research Institute [EPRI] and the Health Effects Institute [HEI]), and industry. Planning and management of research across government agencies and other organizations present a number of continuing challenges, including (1) specific agency missions and differing needs and priorities for research; (2) variability in planning processes and management
systems; (3) differing standards and expectations for ensuring research quality and applying research to policy development; and (4) competition among agencies for resources and influence.
Those and other challenges affect the coordination of PM research across funding agencies, and a lack of sufficient coordination could undermine the effectiveness of research. Coordination has been enhanced through several mechanisms, including (1) EPA as the lead agency in PM research planning can leverage ideas and have some influence on other funding organizations; (2) Congress can participate actively through appropriations, oversight, and staff interest in PM research planning; (3) in part in response to the committee’s earlier reports, an interagency mechanism, the PM workgroup of the Air Quality Research Subcommittee of the Committee on Environment and Natural Resources (CENR), was created to exchange information and plans. Other organizations, such as NARSTO,2 have also provided opportunities for exchange among diverse federal, state, and private organizations, and the online PMRA.org research database developed by EPA and the Health Effects Institute (HEI) has provided a central inventory of the many different activities in the United States and elsewhere.
The CENR PM workgroup and 19 other agencies participate in PM research activities. To date, the workgroup’s activities have focused primarily on sharing information about the PM research activities of federal agencies. It has, however, stopped short of the type of integrated planning and implementation called for in the committee’s reports.
CENR’s efforts have also been limited to federal agencies, leaving the broader communication among diverse programs to NARSTO. NARSTO has recently completed an assessment of atmospheric science relevant to PM that presents recent findings of PM atmospheric science for North America (NARSTO 2003). Beyond CENR and NARSTO, scientific professional societies, industry research organizations, and organizations based on multiple stakeholder partnerships, such as the HEI, are other avenues for research coordination. For the most part, these efforts have provided useful avenues for information exchange, but with a few exceptions (for example, the Fresno Asthmatic Children’s Environment Study [FACES] supported by the California Air Resources Board and coordinated with the Fresno Supersite), none of them has gone beyond information sharing and descrip-
tive activities to create proactive cross-agency research planning and implementation. These efforts have been valuable but have not affected decisions on how the individual agencies allocate and spend their funds.
The committee concludes that existing interagency research coordination efforts to date have helped promote greater awareness of PM-related research needs among federal and state agencies, academic scientists, the private sector, segments of the international research community, and nongovernment stakeholder organizations. However, effective coordination among these parties has not yet been achieved.
The committee recommends that the following additional steps be taken to improve interagency research coordination:
Establish multiagency and agencywide research goals and measures for determining the degree of success in meeting these national goals.
Prepare a multiyear plan for PM research across agencies that states specific research strategies and priorities for achieving PM research goals, provides a staged transition to integrating those goals into a multipollutant approach, and incorporates state and private activities into the federal program. EPA is now working on a multiyear plan for its PM research program (EPA 2003b).
Obtain periodic independent scientific reviews of the multiyear plan and related goals, measures, strategies, and priorities.
Define the specific roles and responsibilities of individual research funding agencies and communicate how their individual plans and capabilities are integrated within a single national multiyear plan, which might ultimately take the form of a unified air pollution research budget across federal agencies.
Enable other nonfederal PM research funding organizations to provide continuing input into the federal planning process, and seek opportunities for additional PM research partnerships.
Expand the transparency of the federal PM research planning process to nongovernment stakeholders.
Beyond these national and North American efforts, international cooperation in air pollution research should also be enhanced through expanded bilateral and multilateral agreements. Such an effort could be highly valuable for national regulatory policies by providing early access to findings of research conducted in foreign countries.
Air pollution by PM and the other pollutants is a national and interna-
tional public health issue that should be coordinated by the many involved governmental and other partners, even though EPA is by mandate in the lead on scientific research and regulation. The committee has not seen sufficient proactive integrated research planning and implementation among the many agencies over the past 6 years, integration that is essential for achieving important and difficult research goals, such as understanding the toxicity of different components of the PM mixture, designing and conducting research on the long-term effects of exposure, and testing models appropriate to use for PM control strategies. The steps listed above are essential and, if taken, will lead to more robust and cost-effective PM research planning and can increase public confidence in the results obtained.
Need for an Ongoing Planning and Oversight Committee
The Committee on Research Priorities for Airborne Particulate Matter was established to develop a policy-relevant scientific agenda for research on airborne PM, monitor progress toward achieving this agenda, and evaluate the gains and benefits of the knowledge acquired. The committee developed several useful tools for conducting its work, including (1) a research portfolio to define and track research needs and progress; (2) a framework to synthesize available information and evaluate the extent to which scientific uncertainties were reduced; and (3) criteria to assess the value of research to policymaking, measure the quality of the research, and determine the extent to which the research was effectively planned and made available to the scientific community and other interested parties.
The completion of this committee’s task through the issuance of this report does not complete the need for ongoing PM research, nor is the task of independently reviewing PM research plans and results finished. Beyond those tasks, the need to move this research agenda increasingly toward a multipollutant approach for health effects and to better inform implementation strategies poses new challenges and opportunities. These tasks are an inherent part of ensuring policy-relevant and high-quality research that sustains public confidence in the process of setting NAAQS.
The need for sustained oversight and advice on implementing this complex research program has grown since 1998. However, such advice is best not given by the same group that has been so closely tied to the development of the program but by a new body that can sustain the effort and bring forth new ideas and direction. The committee recommends, upon
the issuance of this report and the completion of its task, that both EPA and Congress consider establishing a successor to this committee through the year 2010—the time frame for completing the PM research portfolio. Moreover as emphasized elsewhere in the report, it is important that oversight and advice not focus exclusively on PM but also consider other atmospheric constituents that impact on health. There are several ways in which such an ongoing independent mechanism might be established, but several of the principles followed in establishing the current committee could help guide that process. These principles include the following:
A committee representing a diversity of scientific skills, experience in research management, knowledge of policy development, and varied institutional affiliations.
The ability of the committee to engage actively with relevant decisionmakers and participants in the process for managing PM research and setting PM NAAQS so as to assess the most important questions to be answered.
A focus not only on the near term but also on identifying and evaluating research plans and results relevant to short-, medium- and long-term time horizons in ways that reconcile the needs of both scientists and policymakers.
In establishing a new mechanism for independent guidance, care should be taken to balance continuity and fresh thinking by ensuring that the majority have not been involved in the work of the current committee. This new effort should extend its work beyond EPA to include review of PM-related research; plans and budgets across the federal government; and agencies, public and private, other than the federal government. Indeed, there is considerable merit to chartering this new effort to consider broadly all air pollutants and their relationship to health, recognizing the extent to which the effects of individual pollutants are interrelated with those of others.
IMPROVED TOOLS FOR SCIENCE TRACKING AND SYNTHESIS
In the 6 years since the first report of this committee, substantial new literature has been reported that is relevant to the committee’s task. In preparing this report, the committee reviewed hundreds of scientific reports.
EPA’s fourth external review draft criteria document on PM (EPA 2003a), which focuses on new reports since the 1996 criteria document, includes more than 3,200 references in its more than 1,800 pages. The committee developed its own database to organize the most critical references, but the full number of relevant studies could not be captured.
The magnitude and scope of this new science, and the even greater volume of research likely to report out in the coming years, pose both an opportunity and challenge. It provides a rich new resource for understanding the sources and effects of PM. At the same time, the scope of the literature available now exceeds the capacity of the usual integrative mechanism of expert review, given the need to summarize substantial literature on any single facet of PM and to synthesize across different lines of investigation. The committee has identified two key ways to address this substantial opportunity and challenge.
Ongoing Inventory of PM Research and Publications
One positive result of the committee’s earlier reports, and EPA’s implementation of the PM research program, is the development of an interactive, web-based, searchable database of all PM research projects (HEI/EPA 2003). This database contains the projects of all major PM research funding organizations and is searchable by investigator, research focus of project, funding institution, and other variables. It is regularly updated with new projects funded by EPA, HEI, and some other federal agencies, but the process of updating is difficult, especially for atmospheric studies that are funded by multiple agencies. The ability to continue to gain cooperation from other federal agencies is probably also tied directly to the sustained involvement of the EPA program manager.
Perhaps more important, no equivalent effort has been made to develop and maintain a database of all newly published PM research from all relevant fields, including health, exposure, and atmospheric chemistry. Although a catalog of the manuscripts included in the criteria document was developed, that catalog, although machine-readable, is not maintained in a searchable database with key aspects and results of the studies included. The catalog is likely to be kept up to date only until the current criteria document is completed, at which time the process is likely to be suspended until the next PM NAAQS review. The catalog is also not available on the web or in other ways to those in the broader research community who are planning studies and waiting to compare their results with other emerging
data. For both the ongoing review of the NAAQS standards that are required every 5 years, and to support implementation decisions for the NAAQS, EPA will benefit substantially from developing, implementing, and maintaining such a database.
To move forward, EPA should maintain a fully searchable, semiannually updated database of the literature on PM. This database should evolve through stages to include the other air pollutants that make up the atmosphere and should be established and funded in such a way to ensure continued attention to maintaining and updating. Development of this database is not a simple undertaking but is one that should pay dividends to EPA and the broader science community for many years to come. It is also a logical and achievable extension of EPA’s current efforts, in which it already invests substantial resources in identifying scientific publications and organizing findings in the form of criteria documents and other reports. Types of models for such efforts include the much larger Medline database or a more modest searchable database using readily available software to identify publications that address specific aspects of PM research, such as PM exposure in older subgroups.
Improving Information Synthesis
In addressing its charge of gauging research progress, the committee needed to develop an approach for synthesizing research findings. This process is set out in Chapter 2. Even though committees of the National Research Council and of other agencies frequently take on the task of evidence synthesis, the committee found few directly applicable models for this task.
Although many NRC committees are charged with judging causality based on evidence, gauging uncertainties, or evaluating agency research programs, the charge for the committee of this report was focused on judging research progress in terms of scientific and policy value. Although causality of the association of an environmental agent with one or more health effects is a key part of the rationale for developing regulatory standards, our goal was to examine the extent to which uncertainty had been reduced in addressing the 10 research topics that we had framed. Research results on these topics were also available from many fields, requiring us to develop means to synthesize findings and assess progress across research results from multiple scientific disciplines. Despite extensive literature searches and discussions with experts about possible strategies, we were
unable to locate a method previously used for such interdisciplinary research synthesis.
As a result, we developed an approach to meet our charge. We gathered and evaluated research from a wide range of fields—from environmental and source monitoring and modeling to statistical methods, epidemiology, exposure assessment, toxicology, and clinical studies. We examined the quality of studies, judging them on the basis of the standards for the applicable academic discipline. For each topic, we examined the research from each contributing field and developed an overall judgment of the reduction in uncertainty that had occurred for that topic. We considered the state of understanding in 1997 and the amount of new information gained over the following 5 years. Our assessments of progress and scientific and policy value reflect our collective decisions about research progress for each topic (Appendix C).
The body of scientific evidence on PM and other air pollutants is only likely to grow in scope and complexity, and whether future decisions concern NAAQS or setting priorities for control strategies, they will demand enhanced tools and a protocol for assessing and synthesizing the evidence. Such techniques will benefit all decisionmaking agencies, as well as any successor to this committee (as recommended above) and other advisory committees. A standardized approach will make reviews of research programs more efficient, accessible, and comparable across institutions. More experience with methods such as this committee’s is likely to result in continual improvements in strategies for synthesizing and learning from the committee’s substantial investment in developing new answers to difficult questions.
The progress to date on meeting the committee’s research agenda is the result of sustained efforts by EPA, many other organizations, and the scientific community. The continuing needs for scientific research identified in Chapters 4 and 5 will require an even more intensive and well-managed program, both maintaining the momentum that has begun and addressing the underlying management challenges for EPA and other research agencies that have not been addressed to date.