New evidence on the impact of sustained exposure to air pollution on life expectancy from China's Huai River Policy.

Abstract

This paper finds that a 10-μg/m³ increase in airborne particulate matter [particulate matter smaller than 10 μm (PM₁₀)] reduces life expectancy by 0.64 years (95% confidence interval = 0.21-1.07). This estimate is derived from quasiexperimental variation in PM₁₀ generated by China's Huai River Policy, which provides free or heavily subsidized coal for indoor heating during the winter to cities north of the Huai River but not to those to the south. The findings are derived from a regression discontinuity design based on distance from the Huai River, and they are robust to using parametric and nonparametric estimation methods, different kernel types and bandwidth sizes, and adjustment for a rich set of demographic and behavioral covariates. Furthermore, the shorter lifespans are almost entirely caused by elevated rates of cardiorespiratory mortality, suggesting that PM₁₀ is the causal factor. The estimates imply that bringing all of China into compliance with its Class I standards for PM₁₀ would save 3.7 billion life-years.