Research

This paper estimates the causal effect of fine particulate matter (PM2.5) on cardiovascular mortality in the United States using thermal inversions as an instrumental variable. Using county-month-level data from 2010 to 2023, this paper makes two contributions. First, it systematically evaluates how choices in thermal inversion construction affect instrument validity and the reliability of causal estimates. Second, using the preferred construction identified through this evaluation, it finds that a one-unit increase in PM2.5 raises cardiovascular mortality by 3.8 percent. Results are robust to alternative pollutants, mortality outcomes, outcome transformations, PM2.5 measures, nonlinearities, and the exclusion of pandemic years, and the preferred specification passes placebo tests and rules out mortality harvesting. PM2.5 also increases total and respiratory mortality, with no significant effect on cancer mortality. Effects are larger among Black, female, elderly, low-income, and rural populations.

Estimates the causal impacts of smoking on mental health and functional limitations using BRFSS data and cigarette tax variation. Addresses smoking status misreporting via a bivariate probit two-step model, showing that corrected estimates substantially exceed standard estimates.

Many effects of pollution exposure on health and education outcomes of children have been identified, but little is known about education effects on preschool-aged children. We estimate the effect of particulate matter air pollution on preschool attendance using restricted administrative data from the state of Georgia. We use thermal inversions, weather phenomena that trap pollutants, as an instrumental variable for pollution. A one-unit increase in the county-week average ambient particulate pollution level decreases attendance by around 2 percentage points. Effects seem to be larger for racial minorities and for children with working parents. [NBER Working Paper No. w35367]

Uses staggered difference-in-differences over 2010–2019 to estimate whether targeted regulations on abortion providers impose broader financial costs on households beyond direct healthcare access.