The Environmental Protection Agency has joined a beef producers' group in criticizing a 10-year study by California health officials that found more people died in the Coachella Valley on dusty days than clear ones. The federal government cited the research last year among evidence for possible new limits on dust, soot, and other pollution. But the EPA now proposes giving agriculture, mining, and natural sources of "coarse particulate pollution" an exemption from the rules. The National Cattleman's Beef Association took credit on its Web site for protecting farmers and ranchers from having to enact expensive dust controls, stating, "Thanks to...