Diesel Exhaust Goes Unchecked

The 1990 Federal Clean Air Act set limits on how much air pollution is safe. But currently, more than fifty urban areas nationwide violate that law. Much of that pollution is caused by vehicle exhaust. To combat the problem, cars are routinely checked and required to meet certain emissions standards. But diesel trucks have escaped much of that scrutiny. The Great Lakes Radio Consortium’s Steve Frenkel explains why: