Nationwide, diesel pollution causes 21,000 premature deaths each year, according to a report released this week by an environmental group called Clean Air Task Force. To determine diesel pollution's health effects in each U.S. county, the Clean Air Task Force said it employed methodology the U.S. Environmental Protection Agency uses to assess the health benefits of new rules, according to news reports. The group also used the EPA's county-by-county estimates of diesel emissions.The report compares the estimated 21,000 diesel pollution deaths with the 17,000 annual deaths caused by drunk driving and the nation's 20,000 annual homicides.The EPA has issued regulations requiring large reductions in diesel vehicle emissions beginning in 2007, the report said, but the new rules will not affect trucks and buses that are already on the road and will remain in use for an average of nearly 30 years.Allen Schaeffer, executive director of the Diesel Technology Forum, an industry trade group, said he had not thoroughly reviewed the study. Schaeffer questioned whether it relied on outdated information that could make the problem appear worse than it is, according to a report in the Chicago Tribune.More recent EPA data suggest that diesel emissions are responsible for a declining share of the nation's air pollution, in part because diesel engines have steadily become cleaner during the last 15 years, Schaeffer said in the Tribune report."We have demonstrated our commitment to using technology and working together to address these issues," he said. "We're getting cleaner faster than most other industries."