The Impact of Being Downwind from a Coal-Fired Power Plant on Infant Health at Birth: Evidence from the Precedent-Setting Portland Rule

We conduct the first study on the impacts of prenatal exposure to a uniquely identified large polluter, a coal-fired power plant located near the border of two states, on the birth outcomes of the downwind state. For mothers who live as far as 20 to 40 miles away but downwind of the power plant, being exposed to power plant emissions, in particular sulfur dioxide, during the first month of pregnancy could increase the likelihood of having full-term babies but with low birth weight, an indicator of slow fetal growth, by as much as 42 percent. This adverse impact could be driven by reactive sulfur species-induced intrauterine oxidative stress, arising from maternal exposure to emissions of sulfur dioxide, whose traveling from the emission source to the downwind region has been confirmed in the Portland Rule. In light of EPA’s continual efforts in regulating power plant emissions, our study is aimed at broadening the scope of cross-border pollution analysis by taking into account adverse infant heath impacts from upwind polluters, which can burden the downwind states disproportionately.