Mountains of Evidence: The Effects of Abnormal Air Pollution on Crime

This is the first study to assess that air pollution increases criminal activity in a city with air pollution regularly exceeding international safety standards. For winter in Almaty, Kazakhstan, we collect data on crime and PM2.5 pollution across city districts over 8-hour intervals. Our identification strategy employs distinctive features of Almaty's geography: the proximity of some districts to mountain winds and the high frequency of temperature inversions. Using a PPML control function approach, we estimate a PM2.5 elasticity of the expected crime rate equal to 0.38, more than four times as large as elasticity estimates from studies of cleaner cities. Our data and empirical setting also facilitate our identification of air pollution effects on particular crime types. We find that air pollution increases robbery and high-stakes property crime more than low-stakes property crime. These new results support the theory that air pollution induces disregard for criminal consequences and bring further evidence that air pollution induces aggression.