The Long-run Effect of Air Pollution on Survival

Abstract

Many environmental hazards produce health effects that take years to arise, but quasi-experimental studies typically measure outcomes and treatment over short time periods. We develop a new approach to overcome this challenge, focusing on the effect of sulfur dioxide (SO2) exposure on US population mortality. Using changes in wind direction as an instrument for daily pollution levels, we first characterize the short-run mortality effects of acute SO2 exposure during the time period 1972–1988. We then incorporate our estimates into a health production model to quantify the lifelong effects of chronic pollution exposure for a cohort born in 1972. Model calculations of the effect of chronic exposure on life expectancy are 7–8 times larger than a linear extrapolation of our short-run empirical estimates. Ninety percent of the survival benefits accrue after the first fifty years of life, implying that most of the 1970 Clean Air Act’s health benefits have yet to emerge for cohorts born after its passage.

Co-author: Julian Reif