Pollution Trends and US Environmental Policy: Lessons from the Last Half Century

This article proposes and evaluates four hypotheses about US pollution and environmental policy over the last half century. First, air and water pollution have declined substantially, although greenhouse gas emissions have not. Second, environmental policy explains a large share of these trends.本文提出并评估了关于过去半个世纪美国污染与环境政策的四项假说。其一，尽管温室气体排放未出现显著下降，但空气与水污染已得到大幅改善；其二，环境政策在很大程度上解释了这些变化趋势。