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.

Since the beginning of the decade, climate resilient green economy strategies have been proposed in many African countries. One of the pillars of the strategies is the adoption and diffusion of various climate smart agricultural practices for improving crop and livestock production and farmer income while reducing greenhouse gas emissions. The effects of these innovations on household nutritional security, including gender-differentiated nutritional status, have hardly been analyzed.

Little is known about the cost of environmental regulations that target households instead of firms, partly because of significant methodological and data challenges. We use the contingent valuation method to measure the costs of Mexico City’s Day without Driving program, which seeks to stem pollution and traffic congestion by prohibiting vehicles from being driven one day each week. To our knowledge, ours is the first study to focus directly on using stated preference methods to isolate and estimate the private costs of an existing environmental regulation.

A large body of literature estimates the effect of air pollution on health. However, most of these studies have focused on physical health, while the effect on mental health is limited. Using the China Family Panel Studies (CFPS) covering 12,615 urban residents during 2014 – 2015, we find significantly positive effect of air pollution – instrumented by thermal inversions – on mental illness.

The intense debate on the effectiveness of the war on drugs contrasts with the scarce quantitative evidence on its impacts on drug cultivation decisions by individual producers. Using panel data from an original survey of farmers living in coca-growing areas in Colombia, we evaluate the effectiveness of forced eradication policies implemented between 2000 and 2005. We find that one additional hectare eradicated decreases coca supply by 0.44 hectares, indicating that coca can only be eradicated at a very high cost.