FIGURE 1-7 High cancer risk counties for urban air toxics in 1996. SOURCE: EPA 2002c.

those include total compliance with the NAAQS for O₃ and PM and the establishment of a technology-based regulatory program to reduce the emissions of all 188 HAPs (see Figure 1-7). Perhaps even more important, new data on the health effects of O₃ and PM led to the promulgation in 1997 of stricter NAAQS for O₃ and new NAAQS for PM_2.5 that will require even greater reductions in pollutant emissions than had been envisioned at the time the CAA Amendments of 1990 were enacted (see Figure 1-8). EPA (1999a) estimated that complete implementation of the 1990 CAA Amendments costs the nation about $27 billion annually. Most of the costs are directly borne by industry and consumers. Approximately $600 million is expended annually in federal funds, and a large amount is expended by states, tribes, and localities. Of the federal funds, approximately $200 million is dedicated to air quality research and monitoring (OMB 2003b).

Given the sizable investment in air quality management envisioned for the nation over the next decade and the role science and technology can have in optimizing the effectiveness of this investment, the following ques-