Despite the prevalence of drinking water contamination in the United States, its health effects are not well understood. Unlike the extensive research on health impacts of air pollution, studies on water contamination are limited, mainly due to a lack of high-frequency water contamination data. To address this gap, I construct a novel dataset of monthly nitrate contamination levels in California’s community water systems linked with individual birth records. Nitrate contamination is a persistent issue in water systems in the United States, posing a potential threat to infant health. This study estimates the effect of prenatal exposure to nitrate contamination below current regulatory limits on birth outcomes. Using a panel fixed-effects approach with water system and time fixed effects, I compare birth outcomes across infants from the same water system who were exposed to differing levels of nitrate contamination during each trimester of gestation. I find that second-trimester exposure to nitrate concentrations below regulatory limits increases the likelihood of preterm birth and low birth weight by 1.2 and 1 percentage point, respectively. Relative to sample means, these estimates translate to a 15 % increase in the probability of preterm birth and a 17 % increase in the probability of low birth weight birth. Results further suggest that lowering the current regulatory limit below 5 mg/L (half the current limit) could prevent nitrate-related adverse birth outcomes.
While the existing economic literature has extensively examined the effect of privatization on efficiency and profitability, its impact on quality remains underexplored. Understanding this relationship is particularly important in sectors where quality is essential for human health. This study investigates how privatizing U.S. drinking water systems affects quality. Given the competing incentives and regulatory pressures that influence a firm's quality decisions, the ultimate impact of privatization is theoretically ambiguous. Using hand-collected data on municipal systems sold to private companies and employing a propensity-weighted difference-in-differences approach, I find that privatization leads to 1.4 fewer Safe Drinking Water Act violations, a 20% decrease in an index of regulated contaminant concentrations, and a 30% decrease in an index for contaminants that pose an immediate threat to human health. These findings indicate that privatization leads to an overall improvement in drinking water quality and back-of-the-envelope estimates suggest economically meaningful benefits to public health, averaging at least $12.6 million per state in the sample.
The Effect of Stricter Shipping Fuel Sulfur Content Regulation on Air Pollution
Climate Change, Migration, and Health among Older Adults (with Tania Barham, Lori Hunter, and Dylan Connor)
Sweating through the Night: How Nighttime Heat Affects Student Outcomes (with Grant Webster)