Long-run pollution exposure and mortality: Evidence from the Acid Rain Program

•The Acid Rain Program (ARP) caused a dramatic decline in SO2 emissions.•We study the impact of ARP-related pollution reductions on mortality by US counties.•We leverage an atmospheric transport model to explore differential health benefits.•Counties with greater pollution reductions experienced decreases in cardiorespiratory mortality.•Number of lives saved increased over time, implying abatement policies have cumulative benefits. We estimate the effects of long-run pollution exposure on mortality by exploiting the United States Acid Rain Program (ARP) as a natural experiment. We use a difference-in-differences design to compare changes in adult mortality over time driven by installations of sulfur controls on power plants, combined with a model of atmospheric pollution transport. We find that sulfur controls reduced pollution immediately, with smaller relative improvements in the following years. Mortality reductions started small and grew steadily, suggesting cumulative health effects over time. We also find persistent mortality effects for those 35–64 years of age, suggesting the ARP had large productivity gains for the working-age population.