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. [PDF] [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 CapacityHealth 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.

The Effect of Free School Meals on Household Food Purchases: Evidence from the Community Eligibility Provision with Katherine Yewell. Journal of Health Economics 84 (2022): 102646. [Online Appendix] [NBER WP 29395]

We find access 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. The composition of food purchases also changes after CEP, with low income households experiencing a 3 percent improvement in dietary quality. Finally, CEP exposure is associated with 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 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.

Testing the Water: Drinking Water Quality, Public Notification, and Child Outcomes The Review of Economics and Statistics 104.6 (2022): 1289–1303. [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.

A Watershed Moment: The Clean Water Act and Birth Weight with Patrick Flynn [NBER WP 29152] (Accepted at Journal of Human Resources)

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. Using a difference-in-differences framework, we compare birth weight 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.

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

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.

Working Papers
Uncharted Waters: Effects of Maritime Emission Regulation with Jamie Hansen-Lewis [NBER WP 30181] (R&R American Economic Journal: Economic Policy)

Maritime shipping emits as much fine particulate matter as half of global road traffic. We are the first to measure the consequences of US maritime emissions standards on air quality, human health, racial exposure disparities, and behavior. The introduction of US maritime emissions control areas significantly decreased fine particulate matter, low birth weight, and infant mortality. Yet, only about half of the forecasted fine particulate matter abatement was achieved by the policy. We show evidence consistent with behavioral responses among ship operators, other polluters, and individuals that muted the policy’s impact, but were not incorporated in ex-ante models.

Burying the Lead: Effects of Public Lead Service Line Replacements on Blood Lead Levels and Property Values

Despite the well-known health consequences of lead exposure, an estimated 6 to 10 million lead service lines still deliver drinking water to homes throughout the US. Disadvantaged communities are disproportionately exposed to lead service lines, contributing to health and human capital disparities. This paper studies the effects of public lead service line replacements using children’s blood lead test data with confidential address information, home sales data, and geocoded public service line installation data from Rhode Island. Replacing public lead service lines significantly reduces child blood lead levels by about 0.4 units, or 13 percent, and increases the price of home sales by 7-8 percent, indicating that homeowners value these replacements.

Discovery of Unregulated Contaminants in Drinking Water: Evidence from PFAS and Housing Prices with Rosie Mueller

Our understanding of individuals’ response to information about unregulated contaminants in drinking water is limited. Both the public and policymakers have become increasingly concerned regarding the widespread exposure and toxicity of a class of unregulated “forever chemicals” known as per- and polyfluoroalkyl substances (PFAS). We leverage the highly publicized social discovery of PFAS drinking water contamination from one of the largest industrial producers in the US to study the impact of information on housing prices. Using residential property transaction data, we employ a difference-in-differences research design and show that information about PFAS contamination significantly decreased property values of affected homes.

Testing Above the Limit: Drinking Water Contamination and Test Scores

This paper provides the first estimates of the contemporaneous effect of drinking water quality violations on academic test scores in a modern US context. Using student-level test score data with residential addresses, geographic information on water systems, and drinking water violations from North Carolina, I estimate the within-student impacts of poor water quality on student test scores. Exposure to a coliform bacteria violation during the school year decreases math scores by about 3.7 percent of a standard deviation. Effects are not explained by absences, suggesting poor water quality may impact retention or comprehension throughout the school year.

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

Expanding public health insurance to parents may not only benefit parents, but may also have spillover effects on their children. In this paper, we exploit the natural experiment arising from the Affordable Care Act (ACA) to estimate the causal effects of expanding public health insurance to parents on their children’s well-being and to investigate the underlying mechanisms. We find significant improvements in low-income parents’ health care access, health care utilization, and reduced financial burden. However, except for the increased detection of attention deficit hyperactivity disorder (ADHD), the positive spillover effects on children’s well-being are limited in the short term. Nevertheless, given the positive impacts on parents, spillover effects may benefit children in the longer term.

Selected Work In Progress

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