The effect of air pollution on China's internal migration

Have people in China moved from more polluted cities to less polluted ones? We merge city-level air pollution data from 2003 to 2016 with migration data from a nationally representative sample. We estimate a linear model and a conditional logit model, and employ air pollution from distant sources carried by the wind as an instrument for local air pollution to address the potential concern that air pollution is endogenous to local economic activities. We make a distinction between out-migration that left some family members behind and whole-household out-migration, and discover that the former was more responsive to air pollution than the latter. The decline in net in-migration in response to an increase in air pollution was driven by both a decrease in gross in-migration and an increase in gross out-migration. We find suggestive evidence that out-migrants brought their children with them, but some aged parents were left behind.