Poisoned air, shortened lives: PM2.5 exposure and premature mortality in Southern European cities

The study examines the causal effect of PM2.5 air pollution exposure on premature mortality in Southern European cities from 2010 to 2018. We leverage local variations in precipitation and wind speed as a source of random variation in 𝑃𝑀2.5 exposure. Using the Two-Sample Two-Stage Least Squares (TS2SLS) estimator to reconcile monitoring station-level and city-level data, our findings reveal a statistically significant increase in premature mortality caused by PM2.5. According to our preferred specification, a 1% increase in 𝑃𝑀2.5 causes a 0.82% rise in the under-65 mortality rate and a 0.93% rise in the infant mortality rate. The results are robust to alternative specifications. The most affected populations are those residing in urban areas (relative to suburban areas) and those living in cities located in richer regions (as opposed to poorer ones). We also examine the role of additional pollutants, finding further evidence for the importance of particulate matter.