Despite the well-documented dangers of lead exposure, millions of homes still rely on lead service lines (LSLs), contributing to elevated lead levels in drinking water. This article discusses the Lead and Copper Rule Improvements (LCRI), which aim to accelerate the removal of LSLs and to strengthen public health protections. The article highlights the LCRI's key provisions, including mandatory LSL replacement throughout the country within 10 years, stricter lead action levels, improved tap sampling methods, required testing in schools, and expanded public communication and transparency. Although the LCRI represents significant progress, challenges related to funding, legal barriers, and equitable implementation remain. Addressing these obstacles is crucial for achieving the goal of eliminating lead exposure through drinking water and protecting vulnerable populations, especially children.

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 a 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. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

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.

This paper provides estimates of the contemporaneous effect of drinking water quality violations on students’ academic achievement. 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 bacteria violation during the school year decreases math scores by about 0.038 standard deviations when the public is uninformed. Results suggest that poor water quality may impact retention or comprehension of material throughout the school year.

Our understanding of individuals' response to information about unregulated contaminants is limited. We leverage the highly publicized social discovery of unregulated PFAS (per- and polyfluoroalkyl substances) contamination in public drinking water to study the impact of information about unregulated contaminants on housing prices. Using residential property transaction data, we employ a difference-in-differences research design and show that high profile media coverage about PFAS contamination significantly decreased property values of affected homes. We also find suggestive evidence of residential sorting that may have worsened environmental inequality.

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.

Objective: Our objective was to determine whether state SUNucate laws – which have been adopted by 27 states and require schools to permit youths to carry and apply sunscreen on school grounds – were associated with changes in Google Search behavior for words and phrases related to sun protection as well as self-reported sunscreen use by youths. Methods: This was an observational study examining: (1) Google Trends search popularity for terms such as "sunscreen" and "SPF" by state, month, and year for 2004-2022; and (2) self-reported sunscreen use by high school youth in the national Youth Risk Behavior Survey during 2009-2019. Results: State SUNucate laws were associated with increased Google search popularity of terms related to sun protection. Google search popularity for ‘sunscreen’ increased by 27.2% (95% CI 12.67% to 41.7%; p < .001). State SUNucate laws were also associated with increased sunscreen use among high school youths by 8.3% (95% CI 0.014% to 15.0%; p < .05). Conclusion: State SUNucate laws may be effective tools for increasing population search behavior for sun protection terms and youth sunscreen use.

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.

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.

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 to 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.

Health-based drinking water violations affect about one in twelve Americans annually, yet 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.

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 birthweight 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 birthweight, 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. (JEL I12, K32, L71, L78, Q35, Q51, Q53)

Gasoline content regulations are designed to curb pollution and improve health, but their 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 content 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.