As the Wind Blows: The Effects of Long-Term Exposure to Air Pollution on Mortality

There is strong evidence that changes in air pollution levels negatively impact infant mortality and birthweight, but the causal link between long-term exposure to air pollution and increased adult mortality has proven more difficult to confirm.  This project estimates the impact of long-term exposure to air pollution on mortality by leveraging quasi-random variation in pollution levels generated by wind patterns near major highways. We combine geocoded data on the residence of every decedent in Los Angeles over six years, wind data from the National Oceanic and Atmospheric Administration (NOAA), and Census Short Form data. Using these data we compute Census Block-level mortality rates for different age groups and estimate the effect of predicted exposure to highway-generated pollutants on the age-specific mortality rate by using bearing to the nearest major highway as an instrument for pollution exposure.  Preliminary results suggest that Census blocks that lie within 2 kilometers of highways and are predominantly downwind (based on nighttime winds) have higher cardiorespiratory mortality rates among 60+ year olds than Census blocks that lie within 2 kilometers of highways and are predominantly upwind.