Air Quality and Suicide

We conduct the first-ever large-scale study of the relationship between air pollution and suicide using detailed cause of death data from all death certificates in the U.S. between 2003 and 2010. Using wind direction as an instrument for daily pollution exposure, we find that a 1 μg/m3 increase in daily PM2.5 is associated with a 0.49% increase in daily suicides and 0.171 more suicide-related hospitalizations (a 50% increase). Estimates using 2SLS are larger and more robust, suggesting a bias towards zero arising from measurement error. Event study estimates further illustrate that contemporaneous pollution exposure matters more than exposure to pollution in previous weeks.