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 (Forthcoming at American Economic Journal: Applied Economics)

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 (Forthcoming at Journal of Association of Environmental and Resource Economists) [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 derived 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.

Working Papers
Testing the Water: Drinking Water Quality, Public Notification, and Child Outcomes (Revise & Resubmit at The Review of Economics and Statistics)

Health-based drinking water violations affect about 1 in 12 Americans each year, yet we know relatively little about the health benefits of drinking water regulation. In this first study of the impact of drinking water violations on children and adolescents in the US, I exploit plausibly exogenous variation in the timing of water quality violations to estimate the within-location impacts of poor water quality on avoidance behavior and child outcomes. Using data on household purchases of bottled water and common stomach remedies, emergency room visits for gastrointestinal illness, and school absences, I provide a comprehensive calculation of the costs associated with poor drinking water quality. Individuals successfully avoid 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.

Pollution at Schools and Children’s Aerobic Capacity (Revise & Resubmit at Journal of Environmental Economics and Management)

Poor respiratory health is a major cause of mortality and morbidity worldwide. As required by the Clean Air Act, the EPA sets National Ambient Air Quality Standards (NAAQS) to protect public health, including the health of sensitive populations such as children. Existing research has documented the effect of pollution on severe health outcomes, such as hospitalizations for asthma and infant death. However, there is little evidence on how air pollution affects less extreme measures of respiratory health, suggesting that previous literature could underestimate the costs of air pollution. Less extreme effects on respiratory health are possible at levels even below the EPA’s thresholds, but these effects are difficult to measure. I use a more sensitive measure, aerobic capacity (VO2max), to study the impact of air pollution on respiratory health. 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 of fluctuations in daily pollution levels on student aerobic capacity. Ozone affects child aerobic capacity at levels even below the EPA thresholds. I explore heterogeneous effects by race, ethnicity, income, and gender, and find the effects are especially large for disadvantaged groups.

The Impact of Maritime Emissions Standards on Air Quality and Infant Health (with Jamie Hansen-Lewis)

The bulk of ship traffic occurs near coastlines and pollution from ship exhaust is a major component of poor air quality on populated US coasts. In this paper, we measure the effect of maritime fuel emissions standards on air quality and infant health.
We employ the predictions of an atmospheric aerosol transport model to form a rigorous scientific prior on the change in air pollution from maritime emissions standards at a given location accounting for the atmospheric dispersion, disposition, and chemical interactions of pollution once emitted. We combine these predictions with administrative data of air quality and births to estimate the policy’s outcomes and to directly compare the ex-post changes in air pollution from the policy with the ex-ante scientific predictions. We find that the introduction of maritime emissions control areas around the US West Coast led to a substantial 65% average fall in sulfur dioxide concentrations as well as a 5.0% fall in fine particulate matter and  6.8% fall in coarse particulate matter. Consistent with the air quality improvements, we find a 2.7% average reduction in the incidence of low infant birth weight due to the policy. While we cannot reject that the ex-ante and ex-post estimates are the same, we estimate that roughly 75% of the intended fine particulate matter improvements were actualized.

A Little Pain for Birth Weight Gain: Influenza Vaccine Match Rate and Neonatal Health  (with Desislava Byanova and Joseph Acquah)

Research studying short and long-run impacts of influenza are predominantly focused on flu pandemics, when the negative implications are most stark. However, many of these pandemics occurred in the early 20th century before the substantial decline in influenza-related mortality driven by new medical technologies and advancement in hygiene practices. Consequently, the impact of the modern day non-pandemic influenza season may be substantially different from the impact of pandemics occurring in the early part of the 20th century. This paper exploits exogenous variation in vaccine match rate quality and addresses the endogeneity of seasonal influenza severity and vaccination rates by using absolute humidity and an exogenous vaccine supply shock as instruments, in order to quantify the impact of seasonal influenza severity and vaccine effectiveness on birth outcomes in a developed, modern day context. Findings indicate that a one-standard-deviation increase in the vaccine match rate or the vaccination rate leads to a 4 percent or 2 percent decrease in the probability of low birth weight and a 9 percent or 4 percent decrease in the probability of preterm birth, respectively.

The Effect of Free School Meals on Household Food Purchases: Evidence from the Community Eligibility Provision (with Katherine Yewell)

New draft coming soon.

Designed to increase access to meals for low-income students, the Community Eligibility Provision (CEP) eliminates applications for free and reduced-price school meals and allows high poverty schools to provide free meals for all students, regardless of their family income. This paper considers the effects of access to free school meals through CEP on household grocery spending, diet composition, and food security for households with school-aged children using the Nielsen consumer panel data from 2004-2016 and the Current Population Survey from 2001-2018. We find that household spending on grocery purchases decreases after children gain access to free school meals by about $25 per month or 13% of all food spending. Overall diet quality of purchases decreases by about 15.5% from the mean. Evidence that previously eligible households experience large effects on grocery spending, combined with evidence of large reductions in food insecurity from CEP, suggest that application and stigma costs of free school meals may have prevented already-eligible households from participating prior to the adoption of CEP.

A Watershed Moment: The Clean Water Act and Infant Health (with Patrick Flynn)

Draft available on request.

The Clean Water Act (CWA) led to significant improvements in surface water quality, but at a cost exceeding the estimated benefits. This paper is the first to quantify the impact of the Clean Water Act on a direct measure of health and to consider whether incorporating health benefits alters the conclusion of a cost-benefit analysis. We use a difference-in-differences framework to compare infant health outcomes upstream and downstream from wastewater treatment facilities before and after the facility receives a CWA grant. Using facility-level information on compliance with the CWA’s new treatment technology standards, we show that improvements in surface water quality were larger for facilities that were newly required to upgrade their treatment technology. We leverage this information in a triple difference design, using counties up and downstream from facilities that were not bound by the CWA’s treatment technology requirements as an additional control group. We find that reductions in surface water pollution from the CWA are associated with an 8 gram increase in average birth weight. These results are driven by counties whose public water supply systems draw from surface water rather than groundwater. A back-of-the-envelope calculation finds that the monetary benefits of the CWA’s effects on infant health are below 27 billion dollars, or 13.5 percent of the amount necessary to consider the Clean Water Act cost-effective.

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)

Effects of State Restrictions on Indoor Tanning on the Indoor Tanning Market and Tanning-Related Behaviors (with Christopher S. Carpenter and Brandyn Churchill)