When Must EPA Set Ambient Air Quality Standards? Looking Back at NRDC v. Train

There has been much controversy about whether the U.S. Environmental Protection Agency must set ambient air quality standards under the Clean Air Act for gasses that cause global warming. This paper examines NRDC v Train, the precedent suggesting that EPA has such an obligation. That case forced EPA to set ambient air quality standards for lead. The paper suggests that the reasoning behind the decision is quite weak. The paper also examines the history of the regulation of lead, and points out that the ambient air quality standards for lead have had little importance. Thus the paper suggests that ambient air quality standards might not be an important tool for regulating emissions that cause global warming