Diesels Lunge Emissions Goal Line

摘要

The Clean Air Act that created the Environmental Protection Agency in the early 1970s set a distant, ambitious goal to clean America's air enough to protect public health, especially for babies, the elderly, and others with respiratory weakness. Manufacturers of heavy-duty diesel engines have cut nearly 90 percent of pollutants leaving their products' exhaust stacks, and they are striving to clean up what may turn out to be the hardest 8 percent of all.