Air Pollution and Procyclical Mortality

Prior research demonstrates that mortality rates increase during economic booms and decrease during economic busts, but little is known about the role of environmental risks as a potential mechanism for this relationship. We investigate the contribution of air pollution to the procyclicality of deaths by combining county-level data on overall, cause-specific, and age-specific mortality rates with county-level measures of ambient concentrations of three types of pollutants and the unemployment rate. After controlling for demographic variables and state-by-year fixed effects, we find a significant positive correlation between pollution concentrations and mortality rates. Controlling for carbon monoxide, particulate matter, and ozone attenuates the relationship between overall mortality and the unemployment rate by 17%. The findings are robust to the use of state- rather than county-level data and to a variety of alternative specifications, although the attenuation of the unemployment-mortality relationship after controlling for pollution is insubstantial when including county-specific linear trends.