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Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals of increasing concern to human health. PFAS contamination in water systems has been linked to a variety of sources including hydrocarbon fire suppression activities, industrial and military land uses, agricultural applications of biosolids, and consumer products. To assess PFAS in California tap water, we collected 60 water samples from inside homes in four different geographic regions, both urban and rural. We selected mostly small water systems with known history of industrial chemical or pesticide contamination and that served socioeconomically disadvantaged communities. Thirty percent of the tap water samples (18) had a detection of at least one of the 32 targeted PFAS and most detections (89 %) occurred in heavily industrialized Southeast Los Angeles (SELA). The residents of SELA are predominately Latino and low-income. Concentrations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) ranged from 6.8 to 13.6 ng/L and 9.4-17.8 ng/L, respectively in SELA and were higher than State (PFOA: 0.007 ng/L; PFOS: 1.0 ng/L) and national health-based goals (zero). To look for geographic patterns, we mapped potential sources of PFAS contamination, such as chrome plating facilities, airports, landfills, and refineries, located near the SELA water systems; consistent with the multiple potential sources in the area, no clear spatial associations were observed. The results indicate the importance of systematic testing of PFAS in tap water, continued development of PFAS regulatory standards and advisories for a greater number of compounds, improved drinking-water treatments to mitigate potential health threats to communities, especially in socioeconomically disadvantaged and industrialized areas.

Shakespeare's writing responded to ecological problems in his own time. Today, we can adapt his works to speak to the urgent environmental crises facing our communities, as the group Shakespeare in Yosemite does every spring.Based on the final chapter of Katherine Steele Brokaw's Shakespeare and Community Performance (Palgrave Macmillan, 2023) and “Shakespeare and Environmental Justice: Collaborative Eco-Theatre in YosemiteNational Park and the San Joaquin Valley.” In Situating Shakespeare Pedagogy in  US Higher Education: Social Justice and Institutional Contexts. Edited by Marissa Greenberg and Elizabeth Williamson (Edinburgh University Press, 2024). Also based on the work of Shakespeare in Yosemite, https://yosemiteshakes.ucmerced.edu.

BACKGROUND: National-scale linear regression-based modeling may mischaracterize localized patterns, including hyperlocal peaks and neighborhood- to regional-scale gradients. For studies focused on within-city differences, this mischaracterization poses a risk of exposure misclassification, affecting epidemiological and environmental justice conclusions. OBJECTIVE: Characterize the difference between intraurban pollution patterns predicted by national-scale land use regression modeling and observation-based estimates within a localized domain and examine the relationship between that difference and urban infrastructure and demographics. METHODS: We compare highly resolved (0.01 km2) observations of NO2 mixing ratio and ultrafine particle (UFP) count obtained via mobile monitoring with national model predictions in thirteen neighborhoods in the San Francisco Bay Area. Grid cell-level divergence between modeled and observed concentrations is termed localized difference. We use a flexible machine learning modeling technique, Bayesian Additive Regression Trees, to investigate potentially nonlinear relationships between discrepancy between localized difference and known local emission sources as well as census block group racial/ethnic composition. RESULTS: We find that observed local pollution extremes are not represented by land use regression predictions and that observed UFP count significantly exceeds regression predictions. Machine learning models show significant nonlinear relationships among localized differences between predictions and observations and the density of several types of pollution-related infrastructure (roadways, commercial and industrial operations). In addition, localized difference was greater in areas with higher population density and a lower share of white non-Hispanic residents, indicating that exposure misclassification by national models differs among subpopulations. IMPACT: Comparing national-scale pollution predictions with hyperlocal observations in the San Francisco Bay Area, we find greater discrepancies near major roadways and food service locations and systematic underestimation of concentrations in neighborhoods with a lower share of non-Hispanic white residents. These findings carry implications for using national-scale models in intraurban epidemiological and environmental justice applications and establish the potential utility of supplementing large-scale estimates with publicly available urban infrastructure and pollution source information.

This study delves into the energy and emissions impacts of Shared Autonomous and Electric Vehicles (SAEVs) on disadvantaged communities in California. It explores the intersection of evolving transportation technologies—electric, autonomous, and shared mobility—and their implications for equity, energy consumption, and emissions. Through high-resolution spatial and temporalanalyses, this research evaluates the distribution of benefits and costs of SAEVs across diverse populations, incorporatingenvironmental justice principles. Our quantitative findings reveal that electrification of the vehicle fleet leads to a 63% to 71% decrease in CO2 emissions even with the current grid mix, and up to 84%-87% under a decarbonized grid with regular charging. The introduction of smart charging further enhances these benefits, resulting in a 93.5% - 95% reduction in CO2 emissions. However, the distribution of these air quality benefits is uneven, with disadvantaged communities experiencing approximately 15% less benefits compared to more advantaged areas. The study emphasizes the critical role of vehicle electrification and grid decarbonization in emissions reduction, and highlights the need for policies ensuring equitable distribution of SAEV benefits to promote sustainable and inclusive mobility.View the NCST Project Webpage

The historical impacts of transportation planning and investment have left lasting scars on communities of color and low-income communities. This research evaluates online equity tools that exist as spatial dashboards —i.e., interactive maps in which the parameters of interaction are controlled. Twelve tools ranging from the national to the local level were identified and qualitatively assessed for their ability to address conditions related to transportation equity. The evaluation focused on how each tool defines disadvantaged communities, the outcomes they measure (benefits, burdens, or other), their ease of use, and their ability to guide decisions about equity. The findings show a diversity of methods and metrics in defining disadvantage, with most relying on composite demographic indexes and comparative population thresholds. Tools most commonly provided accessibility metrics to assess transportation benefits, while incorporating a range of environmental and health indicators as burden measures. A minority of tools had integrated features to support planning or project implementation. This study provides examples of promising practices in transportation equity support tools.

BACKGROUND AND AIM[|]Traffic-Related Air Pollution (TrAP) adversely impacts human health, disproportionately harming disadvantaged communities. New technologies and infrastructure offer opportunities to reduce TrAP, but the health outcomes of individuals are not fully understood due to a lack of high-resolution models that grasp the complexities of transportation systems and their health implications amid evolving policies and technologies.[¤]METHOD[|]We introduce BEAM CORE (beam.lbl.gov), a high-resolution, agent-based transportation framework that simulates detailed passenger and freight activities. It captures interactions between transportation, land use, demographic and vehicle ownership changes at various scales. Validating crucial factors of emission modeling, including link-level VMT, speed and regional fleet in the San Francisco Bay Area’s nine counties, demonstrates its potential to be extended for assessing health outcomes from changes in TrAP.[¤]RESULTS[|]All major outputs from the BEAM CORE 2018 baseline have been calibrated and validated. Mode split and demographics align closely with census and survey data. Passenger and freight activities were validated against public and private data, with CO2 emissions corresponding to 3.67Mt/yr for medium/heavy-duty (MHD) and 22.79Mt/yr for all vehicles, demonstrating the model’s alignment with empirical data. The NOx, PM2.5 and PM10 from MHD exhaust, PM brake and tire wear are 14.8kt/yr, 424t/yr and 606.9t/yr under the 2018 baseline with high fractions of conventional vehicles, while the wide adoption of clean truck technologies under 2050 resulted in 87\%, 75\% and 56\% reductions respectively. BEAM CORE generates detailed fleet and activity data at high spatiotemporal resolution, enabling the integration with air quality models, including InMAP/AERMOD, to explore the causal pathway of health impacts from transport policy changes.[¤]CONCLUSIONS[|]We developed a sophisticated multi-dimensional transportation model for integration with advanced air quality, and health assessment models. It enables a thorough analysis of health impacts of transportation policies and technologies across diverse communities. It supports similar analyses in any area using local data.[¤]

Extreme weather events are becoming more severe due to climate change, increasing the risk of contaminant releases from hazardous sites disproportionately located in low-income communities of color. We evaluated contaminant releases during Hurricanes Rita, Ike, and Harvey in Texas and used regression models to estimate associations between neighborhood racial/ethnic composition and residential proximity to hurricane-related contaminant releases. Two-to-three times as many excess releases were reported during hurricanes compared to business-as-usual periods. Petrochemical manufacturing and refineries were responsible for most air emissions events. Multivariable models revealed sociodemographic disparities in likelihood of releases; compared to neighborhoods near regulated facilities without a release, a one-percent increase in Hispanic residents was associated with a 5 and 10% increase in the likelihood of an air emissions event downwind and within 2 km during Hurricanes Rita and Ike (odds ratio and 95% credible interval= 1.05 [1.00, 1.13], combined model) and Harvey (1.10 [1.00, 1.23]), respectively. Higher percentages of renters (1.07 [1.03, 1.11], combined Rita and Ike model) and rates of poverty (1.06 [1.01, 1.12], Harvey model) were associated with a higher likelihood of a release to land or water, while the percentage of Black residents (0.94 [0.89, 1.00], Harvey model) was associated with a slightly lower likelihood. Population density was consistently associated with a decreased likelihood of a contaminant release to air, land, or water. Our findings highlight social inequalities in the risks posed by natural-technological disasters that disproportionately impact Hispanic, renter, low-income, and rural populations.

This capstone project tells the untold story of marine diamond mining, tracing its origins from the shores of Namibia to the fjords of Greenland. Despite the stark differences between these two locales, they share striking similarities in diamond potential. In Namibia, marine diamond mining flourished prior to the country's independence and the establishment of international mining laws, setting a precedent for potential challenges in Greenland's current political landscape. Through in-depth research, stakeholder interviews, and media production, this project fosters an informed storyline for a full-length documentary film. The capstone deliverables encompass a film treatment, budget, film plan, concise trailer, and transcribed interviews, strategically crafted towards securing future support of the project. The outcome of such seeking to advocate for greater transparency in the diamond industry and policies that prioritize both economic development and environmental integrity. The final film will engage audiences worldwide in considering the implications of marine diamond mining for Greenland's evolving climate and economy.CLARITY film treatment can be found here: https://tinyurl.com/ClarityTreatment CLARITY interview transcriptions can be found here: https://tinyurl.com/ClarityTranscriptions

Introduction. Several frameworks exist to measure vulnerability to extreme heat events using a health equity approach, but little evidence validates these measures and their applications. We investigated the degree to which social vulnerability measures and their constituent elements correlate with excess emergency room visits as an outcome measure. Methods. The relationship between six commonly used social vulnerability indicators and measured excess emergency room visit rates (processed by including heat-related illnesses and all-internal causes diagnosis, with considerations for age and heat days) was tested through geospatial analytics and statistical regressions, for both California and Los Angeles County. Results. The vulnerability indicators and the outcome measure were significantly positively associated at the census tract-level but weaker (∼0.2 rs) at the scale of California and stronger (∼0.6 rs) at the scale of Los Angeles County. Hazard-specific vulnerability indicators showed stronger relationships with outcome measures regardless of scale. A Poisson regression model showed a significant inter-county variation, indicating the importance of localized assessments for equitable environmental policies. Conclusion. The findings identify communities that are overburdened by heat and pollution and highlight the need for use of both social vulnerability and indicators of adverse outcomes from excessive heat. Patterns are found across all measures that suggest that populations facing accessibility barriers may be less likely to visit emergency rooms. This suggestion needs to be tested in other environmental settings to draw broader conclusions but has direct implications for environmental scientists and mitigation planners who use these methods.

Legacy effects describe the persistent, long-term impacts on an ecosystem following the removal of an abiotic or biotic feature. Redlining, a policy that codified racial segregation and disinvestment in minoritized neighborhoods, has produced legacy effects with profound impacts on urban ecosystem structure and health. These legacies have detrimentally impacted public health outcomes, socioeconomic stability, and environmental health. However, the collateral impacts of redlining on wildlife communities are uncertain. Here, we investigated whether faunal biodiversity was associated with redlining. We used home-owner loan corporation (HOLC) maps [grades A (i.e., "best" and "greenlined"), B, C, and D (i.e., "hazardous" and "redlined")] across four cities in California and contributory science data (iNaturalist) to estimate alpha and beta diversity across six clades (mammals, birds, insects, arachnids, reptiles, and amphibians) as a function of HOLC grade. We found that in greenlined neighborhoods, unique species were detected with less sampling effort, with redlined neighborhoods needing over 8,000 observations to detect the same number of unique species. Historically redlined neighborhoods had lower native and nonnative species richness compared to greenlined neighborhoods across each city, with disparities remaining at the clade level. Further, community composition (i.e., beta diversity) consistently differed among HOLC grades for all cities, including large differences in species assemblage observed between green and redlined neighborhoods. Our work spotlights the lasting effects of social injustices on the community ecology of cities, emphasizing that urban conservation and management efforts must incorporate an antiracist, justice-informed lens to improve biodiversity in urban environments.

Contaminated drinking water from widespread environmental pollutants such as perfluoroalkyl and polyfluoroalkyl substances (PFAS) poses a rising threat to public health. PFAS monitoring in groundwater is limited and fails to consider pesticides found to contain PFAS as a potential contamination source. Given previous findings on the disproportionate exposure of communities of Color to both pesticides and PFAS, we investigated disparities in PFAS-contaminated pesticide applications in California based on community-level sociodemographic characteristics. We utilized statewide pesticide application data from the California Department of Pesticide Regulation and recently reported concentrations of PFAS chemicals detected in eight pesticide products to calculate the areal density of PFAS applied within 1 km of individual community water systems' (CWSs) supply wells. Spatial regression analyses suggest that statewide, CWSs that serve a greater proportion of Latinx and non-Latinx People of Color residents experience a greater areal density of PFAS applied and greater likelihood of PFAS application near their public supply wells. These results highlight agroecosystems as potentially important sources of PFAS in drinking water and identify areas that may be at risk of PFAS contamination and warrant additional PFAS monitoring and remediation.

Contemporary resource management is doubly burdened by high rates of organic material disposal in landfills, generating potent greenhouse gases (GHG), and globally degraded soils, which threaten future food security. Expansion of composting can provide a resilient alternative, by avoiding landfill GHG emissions, returning valuable nutrients to the soil to ensure continued agricultural production, and sequestering carbon while supporting local communities. Recognizing this opportunity, California has set ambitious organics diversion targets in the Short-Lived Climate Pollutant Law (SB1383) which will require significant increases (5 to 8 million tonnes per year) in organic material processing capacity. This paper develops a spatial optimization model to consider how to handle this flow of additional material while achieving myriad social and ecological benefits through compost production. We consider community-based and on-farm facilities alongside centralized, large-scale infrastructure to explore decentralized and diversified alternative futures of composting infrastructure in the state of California. We find using a diversity of facilities would provide opportunity for cost savings while achieving significant emissions reductions of approximately 3.4 ± 1 MMT CO2e and demonstrate that it is possible to incorporate community protection into compost infrastructure planning while meeting economic and environmental objectives.

BackgroundAlthough ~18 million people live within a mile from active oil and gas development (OGD) sites in the United States, epidemiological research on how OGD affects the health of nearby urban residents is sparse. Thousands of OGD sites are spread across Los Angeles (LA) County, California, home to the largest urban oil production in the country. Air pollution and noise from OGD may contribute to cardiovascular morbidity.ObjectiveWe examined the association between proximity to OGD and blood pressure in a diverse cohort of residents in LA.MethodsWe recruited residents in South LA who lived

Wildfire smoke fine particles (PM2.5) are a growing public health threat as wildfire events become more common and intense under climate change, especially in the Western United States. Studies assessing the association between wildfire PM2.5 exposure and health typically summarize the effects over the study area. However, health responses to wildfire PM2.5 may vary spatially. We evaluated spatially-varying respiratory acute care utilization risks associated with short-term exposure to wildfire PM2.5 and explored community characteristics possibly driving spatial heterogeneity. Using ensemble-modeled daily wildfire PM2.5, we defined a wildfire smoke day to have wildfire-specific PM2.5 concentration ≥15 μg/m3. We included daily respiratory emergency department visits and unplanned hospitalizations in 1,396 California ZIP Code Tabulation Areas (ZCTAs) and 15 census-derived community characteristics. Employing a case-crossover design and conditional logistic regression, we observed increased odds of respiratory acute care utilization on wildfire smoke days at the state level (odds ratio [OR] = 1.06, 95% confidence interval [CI]: 1.05, 1.07). Across air basins, ORs ranged from 0.88 to 1.57, with the highest effect estimate in San Diego. A within-community matching design and spatial Bayesian hierarchical model also revealed spatial heterogeneity in ZCTA-level rate differences. For example, communities with a higher percentage of Black or Pacific Islander residents had stronger wildfire PM2.5-outcome relationships, while more air conditioning and tree canopy attenuated associations. We found an important heterogeneity in wildfire smoke-related health impacts across air basins, counties, and ZCTAs, and we identified characteristics of vulnerable communities, providing evidence to guide policy development and resource allocation.

Wildfires have become more frequent and intense due to climate change and outdoor wildfire fine particulate matter (PM2.5) concentrations differ from relatively smoothly varying total PM2.5. Thus, we introduced a conceptual model for computing long-term wildfire PM2.5 and assessed disproportionate exposures among marginalized communities. We used monitoring data and statistical techniques to characterize annual wildfire PM2.5 exposure based on intermittent and extreme daily wildfire PM2.5 concentrations in California census tracts (2006 to 2020). Metrics included: 1) weeks with wildfire PM2.5 < 5 μg/m3; 2) days with non-zero wildfire PM2.5; 3) mean wildfire PM2.5 during peak exposure week; 4) smoke waves (≥2 consecutive days with

Historical policies have been shown to underpin environmental quality. In the 1930s, the federal Home Owners' Loan Corporation (HOLC) developed the most comprehensive archive of neighborhoods that would have been redlined by local lenders and the Federal Housing Administration, often applying racist criteria. Our study explored how redlining is associated with environmental quality across eight California cities. We integrated HOLC's graded maps [grades A (i.e., "best" and "greenlined"), B, C, and D (i.e., "hazardous" and "redlined")] with 10 environmental hazards using data from 2018 to 2021 to quantify the spatial overlap among redlined neighborhoods and environmental hazards. We found that formerly redlined neighborhoods have poorer environmental quality relative to those of other HOLC grades via higher pollution, more noise, less vegetation, and elevated temperatures. Additionally, we found that intraurban disparities were consistently worse for formerly redlined neighborhoods across environmental hazards, with redlined neighborhoods having higher pollution burdens (77% of redlined neighborhoods vs 18% of greenlined neighborhoods), more noise (72% vs 18%), less vegetation (86% vs 12%), and elevated temperature (72% vs 20%), than their respective city's average. Our findings highlight that redlining, a policy abolished in 1968, remains an environmental justice concern by shaping the environmental quality of Californian urban neighborhoods.

Abstract: Scientific research on the mechanisms to address global warming and its consequences continues to proliferate in the context of an accelerating climate emergency. The concept of climate action includes multiple meanings, and several types of actors employ its use to manage the crisis. The term has evolved to incorporate many of the suggested strategies to combat global warming offered by international bodies, states, nongovernmental organizations, the private sector, and social movements. The present work offers a classification scheme to build a shared understanding of climate action through a lens of environmental justice and just transitions developed by sociologists and others. The classification system includes major institutional and noninstitutional forms of climate action. By identifying the primary forms of climate action, analysts, scholars, policymakers, and activists can better determine levels of success and how different forms of climate action may or may not complement one another in the search for equitable solutions in turning back the rapid heating of the planet.

Water, weather, and climate affect everyone. However, their impacts on various communities can be very different based on who has access to essential services and environmental knowledge. Structural discrimination, including racism and other forms of privileging and exclusion, affects peoples lives and health, with ripples across all sectors of society. In the United States, the need to equitably provide weather, water, and climate services is uplifted by the Justice40 Initiative (Executive Order 14008), which mandates 40% of the benefits of certain federal climate and clean energy investments flow to disadvantaged communities. To effectively provide such services while centering equity, systemic reform is required. Reform is imperative given increasing weather-related disasters, public health impacts of climate change, and disparities in infrastructure, vulnerabilities, and outcomes. It is imperative that those with positional authority and resources manifest responsibility through (1) recognition, inclusion, and prioritization of community expertise; (2) the development of a stronger and more representative and equitable workforce; (3) communication about climate risk in equitable, relevant, timely, and culturally responsive ways; and (4) the development and implementation of new models of relationships between communities and the academic sector.

Problem research strategy and findingsEnvironmental justice (EJ) seeks to correct legacies of disproportionately burdening low-income and Black, Indigenous, and people of color (BIPOC) communities with environmental hazards that contribute to health inequalities. Federal and state policies increasingly require plans to assess and incorporate EJ principles. The current lack of accessible data and plan evaluation on EJ has been a barrier to policy setting and benchmarking. We created a framework for analyzing content across a large corpus of plans by using quantitative text analysis on 461 California city general plans, also known as comprehensive plans. To verify results and identify specific policies, we conducted content analysis on a subset of seven plans. Demonstrating the broad applicability of EJ principles in planning, policies spanned all required elements of general plans: housing, circulation, land use, health, safety, open space, air quality, and noise. We found that the most headway in EJ planning has been made in cities with a majority population of color and well before the 2018 California state mandate to address EJ. Policies were primarily focused on preventing adverse exposures as opposed to correcting for legacies of inequality. Further, although all policies address vulnerable populations and places, very few specifically addressed race or racism. Thus, EJ has been largely operationalized as health equity.Takeaway for practiceWe identified 628 EJ policies focused on vulnerable populations across the seven city plans included in content analysis. The smorgasbord of policy approaches provided fodder for cities across the United States to incorporate an EJ approach to planning. Gaps in focus areas reveal room for policy innovation (e.g., emphasis on language justice, formerly incarcerated individuals, and noise ordinance policing). We invite planners and community advocates to search across California's plans for EJ policy inspiration, and to use the appendix of EJ policies cataloged in this research as a benchmark of city-level innovation.

A healthy ocean is essential for human health, and yet the links between the ocean and human health are often overlooked. By providing new medicines, technologies, energy, foods, recreation, and inspiration, the ocean has the potential to enhance human health and wellbeing. However, climate change, pollution, biodiversity loss, and inequity threaten both ocean and human health. Sustainable realisation of the oceans health benefits will require overcoming these challenges through equitable partnerships, enforcement of laws and treaties, robust monitoring, and use of metrics that assess both the oceans natural capital and human wellbeing. Achieving this will require an explicit focus on human rights, equity, sustainability, and social justice. In addition to highlighting the potential unique role of the healthcare sector, we offer science-based recommendations to protect both ocean health and human health, and we highlight the unique potential of the healthcare sector tolead this effort.

Abstract: Water diversions for agriculture reduce ecosystem services provided by saline lakes around the world. Exposed lakebed surfaces are major sources of dust emissions that may exacerbate existing environmental inequities. This paper studies the effects of water diversions and their impacts on particulate pollution arising from reduced inflows to the Salton Sea in California via a spatially explicit particle transport model and changing lakebed exposure. We demonstrate that lakebed dust emissions increased ambient and concentrations and worsened environmental inequalities, with historically disadvantaged communities receiving a disproportionate increase in pollution. Water diversion decisions are often determined by political processes; our findings demonstrate the need for distributional analysis of such decisions to ensure equitable compensation.

We examine the barrier effects of freeways in California. We analyze the association between freeways and nearby street network connectivity and quantify the frequency and quality of crossings—underpasses or bridges that enable pedestrians and cyclists to cross the freeway. We find that barrier effects are most pronounced in communities of color. We also find that even where crossings exist, they are unpleasant or even hazardous for pedestrians and cyclists because of high-speed traffic on on- and off-ramps, and because large volumes of traffic are funneled through a small number of crossings rather than being distributed over a wider network.

Environmental justice research has focused on the distribution of environmental inequalities, such as proximity to landfills, across the U.S. and globally.BackgroundPublic health research and environmental health research, specifically, have focused on toxic exposure-encompassing individuals or communities that are disproportionately exposed to contaminants that are harmful or potentially harmful to them. Yet, little research has applied critical environmental justice theory-characterized by the idea that marginalized communities need to be treated as indispensable rather than disposable-to the study of toxic exposure. To fill this gap, the current paper offers a case study approach applying critical environmental justice theory to the study of disproportionate and unequal exposure to toxic contaminants.MethodsThis case study is of Kettleman City, a rural, unincorporated community in the heart of California's Central Valley (USA). This community experiences the co-location of environmental hazards, including residing at the intersection of two major highways and hosting a class I hazardous-waste landfill, which is one of the few licensed to accept PCBs. PCBs are a contaminant that has been linked with several adverse health outcomes, including cancers and low birthweight. Residents may also experience poor air quality from proximity to the highways.ResultsThis case highlights the uneven distribution of pollution and environmental degradation that may be shouldered by the community, along with their experiences of adverse health and social impacts. This analysis reveals the importance of incorporating a critical environmental justice perspective to unpack experiences of not only disproportionate exposure but also disproportionate procedural and recognitional inequality.ConclusionsThis research highlights the untapped potential of environmental justice to catalyze exposure science in challenging the unequal distribution of contaminants.

The disproportionate use of chemical straighteners and skin lighteners by women of color is a growing public health concern given the link between product use and adverse health effects. Prior studies examined product use as an individual choice but neglected social-structural factors, which influence beauty perceptions and personal decisions around product use. We used a community-based participatory research approach to characterize product use by demographics and investigated how racialized beauty norms impact use among 297 women and femme-identifying individuals in Northern Manhattan and the South Bronx. Product use varied by race/ethnicity, nativity, and messaging from family and peers. Black respondents were more likely to ever use chemical straighteners than non-Black respondents (OR = 2.0; 95% CI = 1.2-3.2), as were respondents who heard that family members express a preference for straight hair compared with respondents whose family members expressed mixed preferences about hairstyles (OR = 2.0; 95% CI = 1.1-3.7). Compared with non-Asian respondents and respondents born in the United States, Asian respondents and respondents born in other countries, respectively, had threefold higher odds of ever using skin lighteners (Asian: OR = 3.2; 95% CI = 1.4-7.0; born in other countries: OR = 3.4; 95% CI = 1.9-6.1). Respondents' perceptions that others believe straight hair or lighter skin confer benefits such as beauty, professionalism, or youth were associated with greater use of chemical straighteners and skin lighteners. These findings highlight the pervasiveness of racialized beauty norms and point to the need to reduce the demand for and sale of these products through community education, market-based strategies, and public policy.

Vehicle electrification has attracted strong policy support in California due to its air quality and climate benefits from adoption. However, it is unclear whether these benefits are equitable across the state’s sensitive populations and socioeconomic groups and whether disadvantaged communities are able to take advantage of the emission savings and associated health benefits of electric vehicle (EV) adoption. In this study, we analyze the statewide health impacts from the reduction of on-road emissions reduction (from reducing gasoline powered cars) and the increase in power plant emissions (from EV charging) across disadvantaged communities (DACs) detected by using the environmental justice screening tool CalEnviroScreen. The results indicate that EV adoption will reduce statewide primary PM2.5 emissions by 24.02-25.05 kilotonnes and CO2 emissions by 1,223-1,255 megatonnes through 2045, and the overall monetized emission-related health benefits from decreased mortality and morbidity can be 2.52-2.76 billion dollars overall. However, the average per capita per year air pollution benefit in DACs is about $1.60 lower than that in the least 10% vulnerable communities in 2020, and this disparity expands to over $31 per capita per year in 2045, indicating that the benefits overlook some of the state's most vulnerable population, and suggesting clear distributive and equity impacts of existing EV support policies. This study contributes to our growing understanding of environmental justice rising from vehicle electrification, underscoring the need for policy frameworks that create a more equitable transportation system.View the NCST Project Webpage

In response to COVID-19 pandemic supply chain issues, the State of California issued Executive Order (EO) N-19-21 to use state land to increase warehousing capacity. This highlights a land-use paradox between economic and environmental goals: adding warehouse capacity increases climate pollution and traffic congestion around the ports and warehouses, while there is a deficit of affordable housing and high homeless rates in port-adjacent underserved communities. This study aims to inform regional policymakers and community stakeholders about these trade-offs by identifying current and future supply of anddemand for warehousing and housing in Southern California through 2040. The study uses statistical analysis and forecasting, and evaluates across numerous scenarios the environmental impact of meeting demand for both with the Community LINE Source Model. Warehousing and housing are currently projected to be in high demand across Southern California in future decades, despite short-run adjustments in the post-pandemic period of inflation and net declines in population. Using state land for warehousing creates environmental justice concerns, as the number of air pollution hotspots increases even with electrifyingtrucking fleets, especially when compared against low-impact affordable housing developments. However, low-income housing demand appears to be positively correlated with unemployment, suggesting that the jobs provided by warehousing development might help to ameliorate that concern.

California must operate and maintain an effective and efficient transportation infrastructure while ensuring that the health of communities and the planet are not compromised. By assessing transportation projects using a life-cycle perspective, all relevant emission sources and activities from the construction, operation, maintenance, and end-of-life phases can be analyzed and mitigated. This report presents a framework to assess the life-cycle human health and climate change impacts from six types of transportation projects: (1) Roadways; (2) Marine ports; (3) Logistical distribution centers; (4) Railyards; (5) Bridges and overpasses; and (6) Airports. The framework was applied using an integrated model to assess fine particulate matter (PM2.5) and greenhouse gas (GHG) emissions, noise impacts, and monetized damages (Value of Statistical Life, Social Cost of Carbon) from two case studies: routine resurfacing and vehicle operations on road segments within the San Francisco Bay Area using 2019 data, and annual marine, cargo, rail, trucking, and infrastructure maintenance operations at the Port of Oakland in 2020. The results suggest that emission sources in a project’s supply chain and construction (material production and deliveries, construction activities, fuel refining) can significantly contribute to the full scope of impacts from transportation systems. Equitable mitigation policies (e.g., electrification, pollution control technologies) need to be tailored to address the sources that impact communities the most.

Childhood lead exposure through drinking water has long-term effects on cognition and development, and is a significant public health concern. The comprehensive lead testing of public schools entails high expense and time. In prior work, random forest modeling was used successfully to predict the likelihood of lead contamination in the drinking water from schools in the states of California and Massachusetts. In those studies, data from 70% of the schools was used to predict the probability of unsafe water lead levels (WLLs) in the remaining 30%. This study explores how the model predictions degrade, as the training dataset forms a progressively smaller proportion of schools. The size of the training set was varied from 80% to 10% of the total samples in four US states: California, Massachusetts, New York, and New Hampshire. The models were evaluated using the precision-recall area under curve (PR AUC) and area under the receiver operating characteristic curve (ROC AUC). While some states required as few as 10% of the schools to be included in the training set for an acceptable ROC AUC, all four states performed within an acceptable ROC AUC range when at least 50% of the schools were included. The results in New York and New Hampshire were consistent with the prior work that found the most significant predictor in the modeling to be the Euclidean distance to the closest school in the training set demonstrating unsafe WLLs. This study further supports the efficacy of predictive modeling in identifying the schools at a high risk of lead contamination in their drinking water supply, even when the survey data is incomplete on WLLs in all schools.

PURPOSE OF REVIEW: The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods. RECENT FINDINGS: We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

In the United States, citizens and policymakers heavily rely upon Environmental Protection Agency mandated regulatory networks to monitor air pollution; increasingly they also depend on low-cost sensor networks to supplement spatial gaps in regulatory monitor networks coverage. Although these regulatory and low-cost networks in tandem provide enhanced spatiotemporal coverage in urban areas, low-cost sensors are located often in higher income, predominantly White areas. Such disparity in coverage may exacerbate existing inequalities and impact the ability of different communities to respond to the threat of air pollution. Here we present a study using cost-constrained multiresolution dynamic mode decomposition (mrDMDcc) to identify the optimal and equitable placement of fine particulate matter (PM2.5) sensors in four U.S. cities with histories of racial or income segregation: St. Louis, Houston, Boston, and Buffalo. This novel approach incorporates the variation of PM2.5 on timescales ranging from 1 day to over a decade to capture air pollution variability. We also introduce a cost function into the sensor placement optimization that represents the balance between our objectives of capturing PM2.5 extremes and increasing pollution monitoring in low-income and nonwhite areas. We find that the mrDMDcc algorithm places a greater number of sensors in historically low-income and nonwhite neighborhoods with known environmental pollution problems compared to networks using PM2.5 information alone. Our work provides a roadmap for the creation of equitable sensor networks in U.S. cities and offers a guide for democratizing air pollution data through increasing spatial coverage of low-cost sensors in less privileged communities.

PurposeThe complexities of modern civilization, coupled with challenges including systemic racism and climate change-related impacts, compel public health professionals to break down silos and collaborate towards the shared goals of protecting the wellbeing of current and future generations. This article highlights the growing collaboration between the Maternal and Child Health (MCH) and the Environment (ENV) Sections of the American Public Health Association (APHA) as members bring their collective focus to the protection of children's and pregnant people's environmental health.DescriptionThe MCH Section and the Children's Environmental Health (CEH) Committee of the ENV Section are collaborating on efforts to: inform key stakeholders?including public health and health care professionals, child care professionals, families, and youth?about environmental hazards and climate change impacts to children's and pregnant people's health and wellbeing; and provide tools and guidance about how to best protect these groups and how to advocate for climate action. The CEH Committee embraces a health equity paradigm and intentionally centers environmental, racial, and social justice as integral to effective children's health and climate change initiatives.AssessmentProjects to date include multiple joint sessions about children's environmental health and climate change at APHA's annual meetings, publications and various children's environmental health tools and resources, including a toolkit and lesson plan that equips public health professionals to provide guest lectures at their local high schools on climate change and health, and educational materials for caregivers on extreme heat, wildfires, and ticks and mosquitos.ConclusionThis collaboration could serve as a replicable model that can be applied to other interdisciplinary efforts seeking strategic partnerships to address complex health issues.

The United States government has indicated a desire to advance environmental justice through climate policy. As fossil fuel combustion produces both conventional pollutants and greenhouse gas (GHG) emissions, climate mitigation strategies may provide an opportunity to address historical inequities in air pollution exposure. To test the impact of climate policy implementation choices on air quality equity, we develop a broad range of GHG reduction scenarios that are each consistent with the US Paris Accord target and model the resulting air pollution changes. Using idealized decision criteria, we show that least cost and income-based emission reductions can exacerbate air pollution disparities for communities of color. With a suite of randomized experiments that facilitates exploration of a wider climate policy decision space, we show that disparities largely persist despite declines in average pollution exposure, but that reducing transportation emissions has the most potential to reduce racial inequities.

This project identifies factors that affect three truck-related parameters: idling, searching for parking, and parking demand. These parameters are examined in communities in Kern County California that have high air pollution levels and are located near transportation corridors, industrial facilities, and logistics centers. Daytime truck idling is concentrated in and around commercial and industrial hubs, and nighttime idling is concentrated around major roads and highway entrances and exits. Truck idling, searching for parking, and parking demand correlate with shorter distances from freight-related points-of-interest such as warehouses, increased size of nearby industrial or commercial land use, and proximity to areas of dense population or income inequality. Based onthese findings, policy recommendations include targeted anti-idling interventions, improved truck parking facilities,parking systems that provide real-time availability information to drivers, provision of alternate power sources in parkingfacilities to allow trucks to turn off, cleaner fuels and technologies, enhanced routing efficiency, stricter emission standards, and stronger land-use planning with buffer zones around residential areas.

Associations between neighborhood greenness and socioeconomic status (SES) are established, yet intra-neighborhood context and SES-related barriers to tree planting remain unclear. Large-scale tree planting implementation efforts are increasingly common and can improve human health, strengthen climate adaptation, and ameliorate environmental inequities. Yet, these efforts may be ineffective without in-depth understanding of local SES inequities and barriers to residential planting. We recruited 636 residents within and surrounding the Oakdale Neighborhood of Louisville, Kentucky, USA, and evaluated associations of individual and neighborhood-level sociodemographic indicators with greenness levels at multiple scales. We offered no-cost residential tree planting and maintenance to residents within a subsection of the neighborhood and examined associations of these sociodemographic indicators plus baseline greenness levels with tree planting adoption among 215 eligible participants. We observed positive associations of income with Normalized Difference Vegetation Index (NDVI) and leaf area index (LAI) within all radii around homes, and within yards of residents, that varied in strength. There were stronger associations of income with NDVI in front yards but LAI in back yards. Among Participants of Color, associations between income and NDVI were stronger than with Whites and exhibited no association with LAI. Tree planting uptake was not associated with income, education, race, nor employment status, but was positively associated with lot size, home value, lower population density, and area greenness. Our findings reveal significant complexity of intra-neighborhood associations between SES and greenness that could help shape future research and equitable greening implementation. Results show that previously documented links between SES and greenspace at large scales extend to residents yards, highlighting opportunities to redress greenness inequities on private property. Our analysis found that uptake of no-cost residential planting and maintenance was nearly equal across SES groups but did not redress greenness inequity. To inform equitable greening, further research is needed to evaluate culture, norms, perceptions, and values affecting tree planting acceptance among low-SES residents.

Clean energy technologies provide global benefits through climate mitigation and many local environmental benefits for consumers. However, the supply chains that produce them inevitably impose some environmental burden on the communities where they operate. To align with the principles of environmental justice, the burdens and benefits of clean energy supply chains should be distributed equitably, with decision-making processes that empower local communities to participate. Academic research can play a key role as a source of transparent information that addresses the concerns of frontline communities; however, this requires deliberate effort during the initial stages of research to understand what those concerns are and seek data that will respond to them. As a case study, this article analyzes public meetings about a developing lithium industry in Imperial, California, and reviews relevant literature to build a research agenda that is guided by the priorities of local stakeholders. We find that water consumption, public health impacts, local employment, and opportunities to participate are high-priority topics for community members. We also compare the content of discussions across groups, finding that participants in community-focused meetings mainly asked about the local impacts of the process, whereas state-led discussions focused on the sustainability of direct lithium extraction compared to conventional production methods. To address the priorities of frontline communities, we recommend evaluating water consumption in the context of regional availability, including local air emissions and waste streams in sustainability analyses, and monitoring the impact on local employment over time to ensure the promises made during development accrue to communities.

Mainstreaming of ecosystem service approaches has been proposed as one path toward sustainable development. Meanwhile, critics of ecosystem services question if the approach can account for the multiple values of ecosystems to diverse groups of people, or for aspects of inter- and intra-generational justice. In particular, an ecosystem service approach often overlooks power dimensions and capabilities that are core to environmental justice. This article addresses the need for greater guidance on incorporating justice into ecosystem services research and practice. We point to the importance of deep engagement with stakeholders and rights holders to disentangle contextual factors that moderate justice outcomes on ecosystem service attribution and appropriation in socio-political interventions. Such a holistic perspective enables the integration of values and knowledge plurality for enhancing justice in ecosystem services research. This broadened perspective paves a way for transformative ecosystem service assessments, management, and research, which can help inform and design governance structures that nourish human agency to sustainably identify, manage, and enjoy ecosystem services for human wellbeing.

Air pollution is a major public health threat that is associated with asthma, cardiovascular disease, respiratory disease and all-cause mortality. Among the most important acute air pollution events occurring each year are celebrations involving fireworks, such as the 4th of July holiday in the United States. In this community-engaged study, academic partners and residents collaborated to collect indoor and outdoor PM2.5 concentration measurements in the disadvantaged city of Santa Ana, California, using low-cost AtmoTube sensor devices before, during and after the July 4th firework celebration, while also examining July 4th data extracted from the PurpleAir sensor network across over a hundred other cities in southern California. Average outdoor PM2.5 concentrations on July 4th were found to be three-to-five times higher than baseline, with hourly concentrations exceeding 160 μg/m3. Outdoor averages were roughly 30% to 100% higher than indoor levels. The most polluted cities exhibited 15-times higher PM2.5 levels compared with the least contaminated cities and were often those where household-level fireworks were legal for sale and use. Race/ethnicity was found to be the leading predictor of July 4th-related air pollution across three counties in southern California, with greater PM2.5 being associated with higher proportions of Hispanic residents and lower proportions of White residents. The findings from this study underscore the importance of environmental justice as it relates to firework-related air pollution exposure, and the critical role city- and county-level firework policies play in determining exposure.

ObjectivesWe show that participatory research approaches can be a useful tool across disciplines and data collection methods to explore the socio-exposome near one of the largest industrial harbors in Europe. We analyzed resident involvement in each project and their capacity to affect structural changes.MethodsLongitudinal participatory environmental monitoring studies on lichens, petunias, aquatic systems and groundwater were conducted under the program VOCE (Volunteers for the Citizens' Observation of the Environment), which mobilized nearly 100 volunteers to collect and report data. A community-based participatory health survey, Fos EPSEAL was also carried out during the same period. We describe citizens' involvement in each study following Davis and Ramirez-Andreotta's (2021) 'best practice' grid. We also use residents' insights to refine understanding of the socio-exposome.ResultsThe region is significantly impacted by industrial pollution and fenceline communities are disproportionately exposed. The community-based participatory health survey documented negative health outcomes among the residents, including a higher prevalence of chronic symptoms and diabetes (e.g., 11.9%) in the Fos-Berre Lagoon region than in other communities. This methodology shows the benefits of the co-production of knowledge in environmental health: not only does it enable epistemological transformations favorable to the vulnerable population, but it also triggered public action (i.e., media and public authorities' attention leading to official expertise reports, filing of collective complaints before the courts).ConclusionThis body of multiple participatory research studies over time is a useful approach to better understand the socio-exposome and health issues in an industrial zone.

Low-income, rural frontline communities of California's Central Valley experience environmental and socioeconomic injustice, water insecurity, extremely poor air quality, and lack of fundamental infrastructure (sewage, green areas, health services), which makes them less resilient. Many communities depend financially on agriculture, while water scarcity and associated policy may trigger farmland retirement further hindering socioeconomic opportunities. Here we propose a multi-benefit framework to repurpose cropland in buffers inside and around (400-m and 1600-m buffers) 154 rural disadvantaged communities of the Central Valley to promote socioeconomic opportunities, environmental benefits, and business diversification. We estimate the potential for (1) reductions in water and pesticide use, nitrogen leaching, and nitrogen gas emissions, (2) managed aquifer recharge, and (3) economic and employment impacts associated with clean industries and solar energy. Retiring cropland within 1600-m buffers can result in reductions in water use of 2.18 km3/year, nitrate leaching into local aquifers of 105,500 t/year, greenhouse gas emissions of 2,232,000 t CO2-equivalent/year, and 5388 t pesticides/year, with accompanying losses in agricultural revenue of US$4213 million/year and employment of 25,682 positions. Buffer repurposing investments of US$27 million/year per community for ten years show potential to generate US$101 million/year per community (total US$15,578 million/year) for 30 years and 407 new jobs/year (total 62,697 jobs/year) paying 67 % more than prior farmworker jobs. In the San Joaquin Valley (southern Central Valley), where groundwater overdraft averages 2.3 km3/year, potential water use reduction is 1.8 km3/year. We have identified 99 communities with surficial soils adequate for aquifer recharge and canals/rivers within 1600 m. This demonstrates the potential of managed aquifer recharge in buffered zones to substantially reduce overdraft. The buffers framework shows that well-planned land repurposing near disadvantaged communities can create multiple benefits for farmers and industry stakeholders, while improving quality of life in disadvantaged communities and producing positive externalities for society.

Communities of color and poor neighborhoods are disproportionately exposed to more air pollution-a pattern known as environmental injustices. Environmental injustices increase susceptibility to negative health outcomes among residents in affected communities. The structural mechanisms distributing environmental injustices in the USA are understudied. Bridging the literatures on the social determinants of health and environmental justice highlights the importance of the environmental conditions for health inequalities and sheds light on the institutional mechanisms driving environmental health inequalities. Employing a critical quantitative methods approach, we use data from an innovative state racism index to argue that systematic racialized inequalities in areas from housing to employment increase outdoor airborne environmental health risks in neighborhoods. Results of a multilevel analysis in over 65,000 census tracts demonstrate that tracts in states with higher levels of state-level Black-white gaps report greater environmental health risk exposure to outdoor air pollution. The state racism index explains four-to-ten percent of county- and state-level variation in carcinogenic risk and noncarcinogenic respiratory system risks from outdoor air toxics. The findings suggest that the disproportional exposure across communities is tied to systematic inequalities in environmental regulation and other structural elements such as housing and incarceration. Structural racism is an environmental justice issue.

Abstract: The Intergovernmental Panel on Climate Change (IPCC) identified a lack of “political will” by national leaders as the main obstacle to mitigating the climate emergency in its 2022 report. However, the report makes no mention that contributing to this political deficiency has been rising antidemocracy over the past two decades, furthered by the support of the powerful fossil fuel industry. This article explores the synergy between antidemocratic leaders embracing anti-climate agendas that prioritize oil and gas companies over the rights of their citizens. I conclude by reflecting on possible responses to this bleak reality from members of the global environmental movement. This involves acknowledging the deep complicity of liberal democratic states in extractive capitalism, while also rethinking democratic principles of social equality and political inclusion to ensure that historically underrepresented communities can engage in emancipatory pro-climate political mobilization.

On the 30th anniversary of the Principles of Environmental Justice established at the First National People of Color Environmental Leadership Summit in 1991 (Principles of Environmental Justice), we continue to call for these principles to be more widely adopted. We propose an environmental justice framework for exposure science to be implemented by all researchers. This framework should be the standard and not an afterthought or trend dismissed by those who believe that science should not be politicized. Most notably, this framework should be centered on the community it seeks to serve. Researchers should meet with community members and stakeholders to learn more about the community, involve them in the research process, collectively determine the environmental exposure issues of highest concern for the community, and develop sustainable interventions and implementation strategies to address them. Incorporating community "funds of knowledge" will also inform the study design by incorporating the knowledge about the issue that community members have based on their lived experiences. Institutional and funding agency funds should also be directed to supporting community needs both during the "active" research phase and at the conclusion of the research, such as mechanisms for dissemination, capacity building, and engagement with policymakers. This multidirectional framework for exposure science will increase the sustainability of the research and its impact for long-term success.

Though safe drinking water for all is a global public health goal, disparities in access persist worldwide. We present a critical review of primary-data based environmental justice (EJ) studies on drinking water. We examine their findings in relation to the broader EJ and drinking water literatures. Using pre-specified protocols to screen 2423 records, we identified 33 studies for inclusion. We organized our results using the following questions: (1) what sampling and data collection methods are used; (2) how is (un)just access to water defined and measured; (3) what forms of environmental injustice are discussed; (4) how are affected communities resisting or coping; and (5) what, if any, mechanisms of redress are advocated? We find that while many studies analyze the causes and persistence of environmental injustices, most primary-data studies on drinking water are cross-sectional in design. Many such studies are motivated by health impacts but few measure drinking water exposures or associated health outcomes. We find that, while distinct types of injustice exist, multiple types are either co-produced or exacerbate one another. Recognitional injustice is emerging as an undergirding injustice upon which others (distributional or procedural) can take hold. Tensions remain regarding the role of the state; redress for inequitable water access is often presumed to be the state's responsibility, but many EJ scholars argue that the state itself perpetuates inequitable conditions. The accountability for redress under different forms of water governance remains an important area for future research. This article is categorized under: Human Water > Methods.

The manufacture and production of industrial chemicals continues to increase, with hundreds of thousands of chemicals and chemical mixtures used worldwide, leading to widespread population exposures and resultant health impacts. Low-wealth communities and communities of color often bear disproportionate burdens of exposure and impact; all compounded by regulatory delays to the detriment of public health. Multiple authoritative bodies and scientific consensus groups have called for actions to prevent harmful exposures via improved policy approaches. We worked across multiple disciplines to develop consensus recommendations for health-protective, scientific approaches to reduce harmful chemical exposures, which can be applied to current US policies governing industrial chemicals and environmental pollutants. This consensus identifies five principles and scientific recommendations for improving how agencies like the US Environmental Protection Agency (EPA) approach and conduct hazard and risk assessment and risk management analyses: (1) the financial burden of data generation for any given chemical on (or to be introduced to) the market should be on the chemical producers that benefit from their production and use; (2) lack of data does not equate to lack of hazard, exposure, or risk; (3) populations at greater risk, including those that are more susceptible or more highly exposed, must be better identified and protected to account for their real-world risks; (4) hazard and risk assessments should not assume existence of a "safe" or "no-risk" level of chemical exposure in the diverse general population; and (5) hazard and risk assessments must evaluate and account for financial conflicts of interest in the body of evidence. While many of these recommendations focus specifically on the EPA, they are general principles for environmental health that could be adopted by any agency or entity engaged in exposure, hazard, and risk assessment. We also detail recommendations for four priority areas in companion papers (exposure assessment methods, human variability assessment, methods for quantifying non-cancer health outcomes, and a framework for defining chemical classes). These recommendations constitute key steps for improved evidence-based environmental health decision-making and public health protection.

A key element of risk assessment is accounting for the full range of variability in response to environmental exposures. Default dose-response methods typically assume a 10-fold difference in response to chemical exposures between average (healthy) and susceptible humans, despite evidence of wider variability. Experts and authoritative bodies support using advanced techniques to better account for human variability due to factors such as in utero or early life exposure and exposure to multiple environmental, social, and economic stressors.This review describes: 1) sources of human variability and susceptibility in dose-response assessment, 2) existing US frameworks for addressing response variability in risk assessment; 3) key scientific inadequacies necessitating updated methods; 4) improved approaches and opportunities for better use of science; and 5) specific and quantitative recommendations to address evidence and policy needs.Current default adjustment factors do not sufficiently capture human variability in dose-response and thus are inadequate to protect the entire population. Susceptible groups are not appropriately protected under current regulatory guidelines. Emerging tools and data sources that better account for human variability and susceptibility include probabilistic methods, genetically diverse in vivo and in vitro models, and the use of human data to capture underlying risk and/or assess combined effects from chemical and non-chemical stressors.We recommend using updated methods and data to improve consideration of human variability and susceptibility in risk assessment, including the use of increased default human variability factors and separate adjustment factors for capturing age/life stage of development and exposure to multiple chemical and non-chemical stressors. Updated methods would result in greater transparency and protection for susceptible groups, including children, infants, people who are pregnant or nursing, people with disabilities, and those burdened by additional environmental exposures and/or social factors such as poverty and racism.

Vehicular air pollution has created an ongoing air quality and public health crisis. Despite growing knowledge of racial injustice in exposure levels, less is known about the relationship between the production of and exposure to such pollution. This study assesses pollution burden by testing whether local populations' vehicular air pollution exposure is proportional to how much they drive. Through a Los Angeles, California case study we examine how this relates to race, ethnicity, and socioeconomic status---and how these relationships vary across the region. We find that, all else equal, tracts whose residents drive less are exposed to more air pollution, as are tracts with a less-White population. Commuters from majority-White tracts disproportionately drive through non-White tracts, compared to the inverse. Decades of racially-motivated freeway infrastructure planning and residential segregation shape today's disparities in who produces vehicular air pollution and who is exposed to it, but opportunities exist for urban planning and transport policy to mitigate this injustice.