This paper uses an updated and revised panel data set on ambient air pollution in cities world-wide to examine the robustness of the evidence for the existence of an inverted U-shaped relationship between national income and pollution. We test the sensitivity of the pollution-income relationship...

From 1990 to 2008, the real value of US manufacturing output grew by one-third while the pollution emitted from US factories fell by two-thirds. What accounts for this cleanup? Prior studies have documented that a relatively small share can be explained by changes in the composition of US...