limited to wasting considerable dollars and effort, but, more important, failing to protect people from preventable public-health risks. Such research will be an investment in public health and a means to ensure that resources spent on control technology and regulatory compliance will have a reasonable probability of success. Given the extensive potential consequences of implementing the particulate-matter standards, only both kinds of success are acceptable. The committee is convinced that such success is achievable and that the recommended research can help guide public-health protection and cost-effective regulatory decisions.

It is also important that the scientific community speak with a clear voice in communicating research priorities for airborne particulate matter. Nonscientists in Congress, the Executive Branch, and the American public deserve to have a clear explanation of the state of scientific knowledge and uncertainty regarding particulate matter, what research is needed, and how more research could make a difference in guiding public-health decisions. Scientists have a responsibility to identify opportunities for clarifying the facts underlying important public-policy debates and to demonstrate that science can help resolve important issues that concern the public.

Chapter 2 of this report summarizes previous reviews of particulate-matter research needs and activities by EPA and other organizations. Chapter 3 presents the committee's conceptual framework and decision criteria for developing its research recommendations. The committee's highest-priority research recommendations are presented in Chapter 4. The recommended phasing and estimated costs of these research activities are integrated into a research investment portfolio in Chapter 5. In Chapter 6, the research priorities and strategies recommended by the committee are compared with those previously identified by EPA. Chapter 7 discusses additional aspects of implementing the committee's recommended research strategy.