Tamma Carleton - SMSP Fall Seminar Series 2023

Abstract: Emerging evidence on environmental determinants of brain function suggests that environmental conditions may play a role in declining suicide rates across the globe. Here we investigate whether air quality improvements contribute to falling suicide rates in China. We use county-level suicide and air pollution data in a statistical model that isolates random variation in particulate matter (PM2.5) driven by thermal inversions. We find that a one standard deviation decrease in PM2.5 lowers weekly suicide rates by ~25%. This effect occurs without delay, consistent with neurobiological evidence that PM influences emotional regulation and impulsive-aggressive behavior. Effects are sex- and age-specific; women over 65 exhibit significantly higher vulnerability. We estimate that PM2.5 reductions under China's Air Pollution Action Plan avoided ~46,000 suicides during 2013-2017, accounting for ~10% of this period's suicide rate decline. Our findings establish a causal link between PM2.5 and suicide, adding urgency to calls for pollution control policies across the globe.