Automobiles are a major contributor to pervasive urban air quality problems. Partly to reduce these air quality problems, China has invested heavily in urban subway systems. This paper provides the first comprehensive estimates of the effects of these investments on urban air quality. The analysis uses a unique data set that combines hourly air quality data, daily meteorological data, and characteristics of cities for all major subway projects between 2013 and 2014 in China.

A common policy response to severe air pollution and traffic congestion in developing-country megacities is to ban the driving of vehicles with license plates ending in certain numbers on certain days. We use the contingent valuation method to estimate the costs to drivers of Beijing’s driving restrictions program, one of the world’s largest. Our study generates three main findings.

In recent years, the coal intensity of electricity generation and its change rate over time has varied significantly across coal-fired power plants in China. This paper decomposes the coal intensity change into four components: technological catch-up, technological progress, change in capital-coal ratio, and change in labor-coal ratio.

The shale gas boom in the United States has been reforming the world energy market. The supply response of shale gas to productivity shocks and relative price changes, however, has not been adequately studied. We analyze the change in price responsiveness of shale gas drilling using well-level data covering all major producing reservoirs in the United States. Shale gas drilling becomes more responsive to energy prices after the major productivity shock in 2009.