On the Road to Recovery: Gasoline Content Regulations and Child Health, Journal of Health Economics 54 (2017): 98-123.

Gasoline content regulations are designed to curb pollution and improve health, but the impact on health has not been quantified. By exploiting both the timing of regulation and spatial variation in children’s exposure to highways, I estimate the effect of gasoline regulation on pollution and child health. The introduction of cleaner-burning gasoline in California in 1996 reduced asthma admissions by 8% in high exposure areas. Reductions are greatest for areas downwind from highways and heavy traffic areas. Stringent gasoline content regulations can improve child health, and may diminish existing health disparities.

Going Beneath the Surface: Petroleum Pollution, Regulation, and Health, American Economic Journal: Applied Economics 13.1 (2021): 1-37. [AEA Research Highlight]

This paper quantifies the health impacts of petroleum leaks from underground storage tanks, the effectiveness of tank regulation, and the role of information as a policy tool in the same setting. Exposure to a leaking underground storage tank during gestation increases both the probability of low birth weight and preterm birth by 7-8 percent. Compliance with regulations requiring the adoption of preventative technologies mitigated the entire effect of leak exposure on low birth weight, and information increased avoidance and moving among highly educated mothers. Back-of-the-envelope calculations suggest the health benefits of preventative regulations exceed the upgrade cost to facilities.

The Role of Parallel Trends in Event Study Settings: An Application to Environmental Economics with Pedro H. C. Sant’Anna. Journal of Association of Environmental and Resource Economists 8.2 (2021): 235-275.  [Supplementary Appendix]

Difference-in-Differences (DID) research designs usually rely on variation of treatment timing such that, after making an appropriate parallel trends assumption, one can identify, estimate, and make inference about causal effects. In practice, however, different DID procedures rely on different parallel trends assumptions (PTA), and recover different causal parameters. In this paper, we focus on staggered DID (also referred as event-studies) and discuss the role played by the PTA in terms of identification and estimation of causal parameters. We document a “robustness” vs. “efficiency” trade-off in terms of the strength of the underlying PTA, and argue that practitioners should be explicit about these trade-offs whenever using DID procedures. We propose new DID estimators that reflect these trade-offs and derive their large sample properties. We illustrate the practical relevance of these results by assessing whether the transition from federal to state management of the Clean Water Act affects compliance rates.

Pollution at Schools and Children’s Aerobic Capacity, Health Economics 30.12 (2021): 3016-3031. [PDF] [Appendix]

Poor respiratory health is a major cause of mortality and morbidity worldwide, and children are especially vulnerable. Existing research in economics has documented the effect of pollution on severe health outcomes, such as hospitalizations for asthma and infant death. However, evidence on the effect of air pollution on less extreme measures of respiratory health is limited, because these effects are difficult to measure. Using a more sensitive measure, aerobic capacity (VO2max), I study the impact of air pollution on respiratory performance of children. I combine school-grade level data from the California Physical Fitness Test from 2009-2017 with local air pollution and weather data to estimate the impact on student aerobic capacity of fluctuations in air pollution levels on testing days. Ozone affects child aerobic capacity at levels even below the Environmental Protection Agency thresholds.

Testing the Water: Drinking Water Quality, Public Notification, and Child Outcomes (Forthcoming at The Review of Economics and Statistics) [Online Appendix]

Health-based drinking water violations affect about 1 in 12 Americans annually, the benefits of drinking water regulation are not well understood. I exploit plausibly exogenous variation in water quality violation timing to estimate the impacts on avoidance behavior and child outcomes. Using purchases of bottled water and common stomach remedies, emergency room visits for gastrointestinal illness, and school absences, I provide a comprehensive calculation of costs associated with poor drinking water quality. Individuals avoid the negative health impacts of coliform bacteria violations only when informed immediately. Timely public notification is a cost-effective way to induce avoidance behavior and protect health.

Working Papers
Uncharted Waters: Effects of Maritime Emission Regulation (with Jamie Hansen-Lewis)

New draft coming soon.

The Effect of Free School Meals on Household Food Purchases: Evidence from the Community Eligibility Provision (with Katherine Yewell) [Online Appendix] [NBER WP 29395]

We find evidence that exposure to universal free school meals through the Community Eligibility Provision (CEP) had a meaningful impact on grocery spending for households with children, with monthly food purchases declining by about $11, or 5 percent. For households in zip codes with higher exposure, the decline is as high as $39 per month, or 19 percent. We also show evidence that the composition of food purchases changes, with low income households experiencing an increase in the dietary quality of their food purchases by about 3 percent after CEP. Finally, we show CEP exposure is associated with an 11 percent decline in the percent of households that ran short of money or tried to make their food money go further, and an almost 5 percent decline in households classified as food insecure. Our results on the heterogeneous effects of CEP exposure by prior free/reduced price lunch eligibility reveal large benefits in terms of both spending, dietary composition, and food insecurity for previously eligible low-income families, suggesting that the stigma of free school meals may be declining after universal access.

A Watershed Moment: The Clean Water Act and Infant Health (with Patrick Flynn) [NBER WP 29152]

The Clean Water Act (CWA) significantly improved surface water quality, but at a cost exceeding the estimated benefits. We quantify the effect of the CWA on a direct measure of health and incorporate health benefits into the cost-benefit analysis. Using a difference-in-differences framework, we compare health upstream and downstream from wastewater treatment facilities before and after CWA grant receipt. Pollution only decreased downstream from facilities required to upgrade their treatment technology, and we leverage this additional variation with a triple difference. CWA grants increased average birth weight by 8 grams. A back-of-the-envelope calculation bounds infant health benefits below $29 billion.

Bad Lighting: Effects of Youth Indoor Tanning Prohibitions (with Christopher S. Carpenter and Brandyn Churchill) [NBER WP 29443]

Indoor tanning beds (ITBs) emit UV light at high intensity and have been classified as carcinogenic to humans by the World Health Organization since 2009. We are the first to study the role of state laws prohibiting youths from indoor tanning using a difference-in-differences research design. We find that youth ITB prohibitions reduced population search intensity for tanning-related information. Among white teen girls, ITB prohibitions reduced self-reported indoor tanning and increased sun protective behaviors. We also find that youth ITB prohibitions significantly reduced the size of the indoor tanning market by increasing tanning salon closures and reducing tanning salon sales.

Selected Work In Progress

The Effect of Immigration Enforcement on Immigrant Health Care Utilization and Spillovers to Native Health (with Chloe East)

Expanding Health Insurance to Parents: Effect on Children’s Care Use and Health (with Xuan Zhang)