needed to advance understanding of relationships between ambient concentrations of particulate matter and actual exposures of individuals at high risk of adverse health effects. Methods to perform continuous analyses of ambient concentrations or integral analyses over extended intervals would provide better real-time data for exposure assessment, compliance analyses, pollution-episode identification, and remedy selection. The data generated by improved measurement methods would also be useful for systematic studies of exposure misclassification and measurement error. These studies would enhance the analysis of population distributions of exposures and applications in epidemiological studies.

For each research activity recommended in Chapter 4, the committee provides rough but informed collective-judgment estimates of the cost of such research, based on the knowledge and experience of the committee members (see Appendix A).