The Effects of Historical Housing Policies on Resident Exposure to Intra-Urban Heat: A Study of 108 US Urban Areas

Embodiment of structural racism and multiple sclerosis risk and outcomes in the USA

Disparities in the incidence, prevalence and outcomes of multiple sclerosis (MS) exist in the USA, often to the detriment of Black and Hispanic people. Despite the common misconception that MS is a disease of white people, the incidence is highest in Black people. Disability accumulates faster and at younger ages in Black and Hispanic people with MS than in their white counterparts, and MS-related mortality in early and mid-adulthood is highest in Black people. These differences are often erroneously interpreted as evidence of innate racial or ethnic variations. In this Perspective, we demonstrate how race and ethnicity - social constructs with a limited biological basis that are often assigned by systems of power - can influence biology through lived experiences, a phenomenon termed 'embodiment'. We review how downstream consequences of structural racism can lead to biological outcomes strongly associated with MS susceptibility, such as imbalanced immune system development, dysregulated immune responses to the Epstein-Barr virus and childhood obesity. We also consider how inequitable health-care access and quality, combined with the younger age of onset and higher comorbidity burdens, might explain racial and ethnic disparities in MS prognosis. Our proposed conceptual model offers a roadmap for generating knowledge and implementing interventions to narrow racial and ethnic disparities in MS susceptibility and outcomes.

A Flexible Framework for Urgent Public Health Climate Action

Climate change poses profound threats to human safety, health, and well-being. Public health agencies, especially state, territorial, local, and Tribal health departments, can play an essential role in climate change adaptation and mitigation. Public health climate action can protect health, promote health equity, and increase climate change resilience. The Centers for Disease Control and Prevention has updated its original climate and health framework for practitioners and expanded its utility by developing practical guidance. The revised framework, Building Resilience Against Climate Effects, supports health departments and their partners by providing an accessible approach that can be tailored to different contexts. The framework has been updated to center justice, equity, and belonging; integrate climate change mitigation or reduction of greenhouse gas emissions that cause climate change; and address agency capacity. The Building Resilience Against Climate Effects framework also emphasizes collaboration, especially cross-sectoral and community partnerships, communication, and evaluation. Framework elements, key tactics, and guiding principles are presented in a pragmatic, step-by-step implementation guide. The implementation guide can be used by state, territorial, local, and Tribal health departments to galvanize or expand their engagement with public health climate action, which grows more urgent each year. (Am J Public Health. Published online ahead of print May 22, 2025:e1-e12. https://doi.org/10.2105/AJPH.2025.308061).

Coexposure to extreme heat, wildfire burn zones, and wildfire smoke in the Western US from 2006 to 2020

Climate change drives three heat-related hazards: extreme heat (EH), wildfire burn zones (WFBZs), and wildfire smoke (WFS). Using daily census tract-level data from 2006 to 2020, we investigated when, where, and whom these hazards coexposed in 11 Western US states. Among 18,106 tracts, at least one hazard occurred an average of 32 days (581,867 tract-days) annually. EH-WFS coexposure increased over the study period and was the most frequent coexposure (annual average of 38,218 tract-days). EH-WFS-affected regions varied year to year. WFBZ-involved coexposures were spatially confined and did not increase over time. On average, the most tract-days of EH-WFBZ-WFS coexposure took place in California, Arizona, and Oregon. Among census tracts most exposed to EH-WFBZ-WFS, populations disproportionately consisted of people of older age, with disabilities, and living in poverty. American Indian and Alaska Native individuals disproportionately faced all coexposures. As climate change accelerates, tracking coexposure to multiple hazards can help target resources to protect health.

Electricity inaccessibility across historically redlined and present-day disadvantaged areas in New York City

BACKGROUND

Electricity is crucial in sustaining livelihoods from turning the lights on at night, keeping the refrigerator running to avoid food spoilage, and powering electricity-dependent durable medical equipment such as nebulizers. Thus, electricity inaccessibility may result in adverse outcomes. Like other environmental burdens, electricity inaccessibility may be socially patterned, with disproportionate occurrence in racially and economically marginalized communities.

OBJECTIVE

To evaluate the 2017-2019 distribution of electricity inaccessibility - defined as power outages and energy insecurity - across historical and present-day measures of community racial disadvantage in New York City (NYC).

METHODS

We measured power outages with NYC 311 outage call reports and the System Average Interruption Frequency Index (SAIFI). We calculated energy insecurity as monthly average energy use, leveraging data from the New York State Energy Research and Development Authority. These three electricity inaccessibility metrics were estimated within both historical Home Owners' Loan Corporation (HOLC) graded areas (A, 'best' through D, 'redlined') and present-day racial and economic Index of Concentrations at the Extremes (ICE) census tracts quartiles.

RESULTS

Our study covered 396 HOLC areas and 2218 census tracts in NYC. Historically A-graded areas had fewer 311 outage calls and lower SAIFI. Additionally, the rate of 311 outage calls in the present-day most disadvantaged census tracts was nearly six times that of the most privileged tracts. Persistently disadvantaged areas (i.e., both poor HOLC grade and high ICE) had more power outages than consistently advantaged areas. However, the present-day most disadvantaged census tracts still had more power outages than persistently disadvantaged areas.

IMPACT

This 2017-2019 New York City (NYC) study evaluated the distribution of three electricity inaccessibility metrics in relation to community privilege and disadvantage. Uniquely, we assessed the distribution across historically redlined areas and present-day census tracts. We defined electricity inaccessibility as power outages (311 calls and power interruptions) and energy insecurity (residential energy use). We found that 311 calls and power interruptions were more common in historically redlined areas, present-day disadvantaged census tracts, and persistently disadvantaged areas. These findings indicate proxies for historical racial discrimination, such as redlining, and modern-day community disadvantages impact the access to reliable electricity in NYC.

A Socio-spatial Model of the Risk of Hospitalization from Vulnerability to High Temperatures

Urban heat islands and climate change create increasingly hot environments that pose a threat to the health of the public in urban areas throughout the planet. In Maricopa County, Arizona, --- the hottest metropolitan area in the United States---we have previously shown that the effects of heat on mortality are greater in the social and built environments of low-income and communities of color (predominantly Hispanic/Latinx and Black neighborhoods). In this analysis of morbidity data from Maricopa County, we examined the relationship between heat-related hospitalization and summertime daily maximum air temperatures in groups defined at the census block group level as being at high, medium, or low vulnerability based on a Heat Vulnerability Index that was derived from socio-economic and built-environment data. For all three categories of census block group heat vulnerability, we identified 26°C as the daily maximum air temperature threshold beyond which heat-related hospitalization risk increased rapidly with each 1 °C increase in temperature. Compared to this baseline temperature, the relative risk of hospitalization was greatest in the high vulnerability census block groups and least in the low vulnerability census block groups with intermediate increases in the medium vulnerability census block groups. Specifically, with 26°C as the referent, the relative risks of heat-related hospitalization increased from 0.97 at 27°C to 15.71 at 46°C in the low vulnerability group, from 1.03 at 27°C to 53.97 at 46°C in the medium vulnerability group, and from 1.09 at 27°C to 162.46 at 46°C in the high vulnerability group. Our research helps identify areas with high heat population sensitivity and exposure that can be targeted for adaptation with policies and investments, which include, for example, improving public health safety nets and outcomes, access to affordable energy-efficient housing and health care, energy justice, and modifications to cool the urban built environment. Our hospitalization risk estimates can be incorporated into quantitative risk assessments of heat-related morbidity in Maricopa County.

Persistent Effect of Redlining on Survival from Screenable Cancers in Washington State, 2000-2018

This study examined the extent to which the 1930s Home Owners' Loan Corporation (HOLC) redlining grades are associated with contemporary survival from screenable cancers among residents of three largest cities in Washington State. Redling assigned a mortgage security metric to neighborhoods. We used 2000-2018 data from the Washington State Cancer Registry to examine differences in survival from all-cause and cancer-specific mortality for breast (n = 14,725), cervical (n = 656), colorectal (n = 7,089), and lung (n = 8,365). Survival was examined in HOLC areas graded as A (best); B (still desirable); C (declining); and D (redlined) using Kaplan-Meier and Cox proportional hazards regression techniques. Among patients with breast cancer, the hazard ratio for all-cause mortality was highest for areas graded D followed by C and B. For colorectal and lung cancer, the hazard ratio for all-cause mortality was highest for areas graded C followed by D and B. The estimated marginal slopes for the log hazard of mortality decreased over time in HOLC areas graded A, B, and C for breast and lung cancers, and in areas graded D for colorectal and lung cancers. HOLC grade was not associated with survival among cervical cancer patients. These findings call for efforts to reduce screenable - but often unrecognized - health inequalities associated with residential location.

Examining the Association between Heat Exposure and Crime in Cities across the United States: A Scoping Review

Growing evidence suggests exposure to high temperatures may result in increased urban crime, a known driver of health and health inequity. Theoretical explanations have been developed to describe the heat-crime relationship without consensus yet achieved among experts. This scoping review aims to summarize evidence of heat-crime associations in U.S. cities. Further examination of empirical and translational inconsistencies in this literature will ensure future studies of urban heat-crime relationships in the U.S., and their policy impacts are informed by a thorough understanding of existing evidence. We performed a comprehensive literature search of empirical studies on heat-crime relationships in U.S. cities published between January 2000 and August 2023. The included studies were qualitatively synthesized based on operationalized exposures, outcomes, covariates, methodologies, theoretical framing, and policy implications. In total, 46 studies were included in this review. Most studies (93%) reported significant, positive associations between urban heat exposure and both violent and non-violent crime outcomes. The shape and strength of these associations varied based on operational definitions of urban heat exposures, crime outcomes, and relevant covariates in employed methods. We also found inconsistencies in the theoretical explanations and policy implications reported across studies. Climate-driven extreme heat events are projected to increase in frequency and severity. Our findings underscore the urgency of refining the understanding and translation of the complex relationship between urban heat and crime. In this review, we highlight opportunities to improve the methodological quality and responsible policy translation of future research in U.S. cities, which has implications for research globally.

Land-use and socioeconomic time-series reveal legacy of redlining on present-day gentrification within a growing United States city

Home Owners' Loan Corporation (HOLC) maps illustrated patterns of segregation in United States cites in the 1930s. As the causes and drivers of demographic and land-use segregation vary over years, these maps provide an important spatial lens in determining how patterns of segregation spatially and temporally developed during the past century. Using a high-resolution land-use time series (1937-2018) of Denver, Colorado, USA, in conjunction with 80 years of U.S. Census data, we found divergent land-use and demographics patterns across HOLC categories were both pre-existent to the establishment of HOLC mapping and continued to develop over time. Over this period, areas deemed "declining" or "hazardous" had more diverse land use compared to "desirable" areas. "Desirable" areas were dominated by one land-use type (single-family residential), while single-family residential diminished in prominence in the "declining/hazardous" areas. This divergence became more established decades after HOLC mapping, with impact to racial metrics and low-income households. We found changes in these demographic patterns also occurred between 2000 and 2019, highlighting how processes like gentrification can develop from both rapid demographic and land-use changes. This study demonstrates how the legacy of urban segregation develops over decades and can simultaneously persist in some neighborhoods while providing openings for fast-paced gentrification in others.

Impact of Heat on Respiratory Hospitalizations among Older Adults in 120 Large U.S. Urban Areas

Rationale: Extreme heat exposure is a well-known cause of mortality among older adults. However, the impacts of exposure on respiratory morbidity across U.S. cities and population subgroups are not well understood. Objectives: A nationwide study was conducted to determine the impact of high heat on respiratory disease hospitalizations among older adults (≥65 yr of age) living in the 120 largest U.S. cities between 2000 and 2017. Methods: Daily rates of inpatient respiratory hospitalizations were examined with respect to variations in ZIP code-level daily mean temperature or heat index. For each city, we estimated cumulative associations (lag days 0-6) between warm-season heat (June to September) and cause-specific respiratory hospitalizations using time-stratified conditional quasi-Poisson regression with distributed lag nonlinear models. We estimated nationwide associations using multivariate meta-regression and updated city-specific associations via best linear unbiased prediction. With stratified models, we explored effect modification by age, sex, and race (Black or White). Results are reported as percentage change in hospitalizations at high temperatures (95th percentile) compared with median temperatures for each outcome, demographic group, and metropolitan area. Results: We identified 3,275,033 respiratory hospitalizations among Medicare beneficiaries across 120 large U.S. cites between 2000 and 2017. Nationwide, 7-day cumulative associations at high temperatures resulted in a 1.2% (95% confidence interval, 0.4-2.0%) increase in hospitalizations for primary diagnoses of all-cause respiratory disease, driven primarily by increases in respiratory tract infections (1.8% [95% confidence interval, 0.6-3.0%]) and chronic respiratory diseases and/or respiratory failure (1.2% [95% confidence interval, 0.0-2.4%]). Stronger associations were observed when exposure was defined using the heat index instead of mean temperature. Across the 120 cities, we observed considerable geographic variation in the relative risk of heat-related respiratory hospitalizations, and we observed disproportionate burdens of heat-related respiratory hospitalizations among the oldest beneficiaries (≥85 yr of age) and among Black beneficiaries living in South Atlantic cities. During the 18-year study period, there were an estimated 11,710 excess respiratory hospitalizations due to heat exposure. Conclusions: Results suggest that high temperature and humidity contribute to exacerbation of respiratory tract infections and chronic lung diseases among older adults. Geographic variation in heat-related hospitalization rates suggests that contextual factors largely account for disproportionate burdens, and area-level influences should be further investigated in multicity studies.

An evaluation of intra-university campus temperature variability under variable synoptic weather conditions using mobile transects

Intensive observations were collected in a wide range of synoptic weather conditions to evaluate variability in the intra-urban heat island on the campus of the University of North Carolina at Charlotte between February 2023 and June 2023. An easily reproducible bicycle-based mobile transit route around the university was traversed during 20 afternoon and 20 evening periods. The magnitude of observed temperature range from an individual data collection period is defined as the campus urban heat island intensity, with areas having more anthropogenic modification also having higher temperatures. While other papers have examined the relationship between the city-scale urban heat island intensity and the present weather conditions, this paper aims to disentangle the relationship between present weather conditions and the magnitude of thermal variability across a small intra-urban campus with diverse land use and land cover characteristics. This will contribute to a better understanding of intra-urban heat islands, particularly identifying days where conditions will be highly dangerous in more developed areas, and not in more natural environments. When comparing the standardized mobile-transit observations to the regionally present weather conditions it is evident that clear and calm conditions often enhance both city-scale and campus-scale heat islands, increasing temperature disparities. While the spatial distribution of warm and cool areas across campus remains relatively constant, the campus-scale heat island is significantly modulated by the present weather conditions.

Carceral heat exposure as harmful design: An integrative model for understanding the health impacts of heat on incarcerated people in the United States

In an era of climate change-driven weather events, extreme heat has become the most lethal form of "natural disaster" in the United States. However, its negative consequences are unequally distributed. Incarceration exacerbates vulnerability to heat-related illnesses and deaths. This article reviews and synthesizes a range of literature related to carceral heat exposure to characterize the complex biological, social, infrastructural, financial, and legal mechanisms through which incarcerated people experience heat-related illnesses and deaths. These mechanisms include the location, design, and construction of carceral facilities; structural racism and poverty that lead to the overrepresentation of specific populations within the carceral system; comorbid conditions amongst incarcerated people; the use of medication as a form of control; barriers to medical care; institutional neglect; and the weaponization of heat as a tactic of retaliation. This article also reviews the patchwork regulatory apparatus related to carceral heat exposure, legal efforts to improve protections for incarcerated people, and obstacles to implementing those protections. In reviewing the literature, we find that there is no singular factor that explains how and why incarcerated people are especially vulnerable to the deleterious effects of heat. We offer instead an integrative model for understanding how multiple mechanisms are consolidated by the carceral system, magnifying the vulnerability of incarcerated people to the effects of heat. As social scientists have demonstrated in other contexts, no one dies from a heat wave alone; instead, they experience illness and death as a result of social and infrastructural arrangements that render them vulnerable to the effects of heat. Our aim is to elucidate the specific arrangements through which the carceral system makes people vulnerable to heat. We argue that exposure to debilitating heat and its attendant consequences represent more than a failure of the carceral system - rather, they reveal its fundamentally harmful design.

An exploratory study of household conditions and youth personal exposure to extreme heat during a heatwave in urban Nashville, Tennessee, USA

Extreme heat is the deadliest meteorological hazard and is increasingly affecting the southeastern United States. Health effects of extreme heat are often not felt for hours or days after exposure and disproportionately affect vulnerable populations (e.g., youth, minorities). Personal heat exposure research has focused on occupational and everyday heat exposure among adults. To date, heat exposure in teenage populations has not been investigated. This population has unique heat exposure patterns that result from lifestyles that include outdoor jobs (e.g., lifeguard) and participation in outdoor sports. Better understanding of these exposure patterns is needed to reduce youth exposure and illnesses during heat events. Likewise, there have been no studies comparing paired indoor home conditions with individual exposure. Participants (n = 10) wore sensors to collect six days of personal heat exposure data (temperature and humidity) and placed sensors in and around their homes to collect ambient household data. When comparing individual exposure with ambient outdoor conditions and household conditions, this study revealed that: 1) teenagers are less exposed to dangerous heat (> 37.8 °C heat index) during the day; 2) teenagers are more exposed to dangerous heat (> 23.9 °C temperature) at night; 2) some teenagers are exposed to long periods of high heat at night, which is typically a time for heat recovery; and 3) household temperatures are typically not representative of heat exposure. To better understand teen exposure, we recommend future research focus on larger, representative sample sizes, collecting exposure data during the school year, and comparing exposure between heatwave and normal summer conditions.

Uneven heat burden in the sunshine state: Spatial patterns and socio-economic disparities of heat-related illness in Florida

Climate change has increased the frequency and severity of extreme heat events globally, adversely affecting socio-economic conditions and public health. However, extreme heat has disparate effects on different population groups and the socio-economic determinants of its health effects are not well understood. In this study, we analyzed the spatial patterns of heat-related illness (HRI) visit rates at the zip-code level in Florida and applied statistical methods to examine the relationships between HRIs and environmental and socio-economic variables. Hierarchical regression analysis was used to evaluate the socio-economic effects on HRI visit rates under the same heat conditions. This is a two-step approach: we first included heat indicators in the baseline model and then added the socio-economic variables to assess their unique contributions in predicting HRI visits. Our findings indicate that temperature can only explain a small fraction of the variance in HRI cases (R2 = 0.04, p < 0.01), while socio-economic variables show stronger associations (R2 = 0.42, p < 0.01 in urban areas and R2 = 0.20, p < 0.01 in rural areas). Notably, marginalized and disadvantaged populations (e.g., individuals in poverty, those employed in construction, and those with disabilities) are positively associated with HRIs (p < 0.01). These findings highlight the disproportionate impacts of heat-related health issues on disadvantaged groups, calling for climate justice policy interventions. Additionally, a comparative analysis between rural and urban areas revealed different determinants of HRIs. Our study enhances the understanding of the socio-economic determinants and disparities of HRIs in Florida, providing actionable insights for policymakers and health agencies to prioritize emergency services and heat resilience planning.

Race, historical redlining, and contemporary transportation noise disparities in the United States

BACKGROUND

Legacies of discriminatory federal housing practices-e.g., racialized property appraisal by the Home Owners' Loan Corporation (HOLC) and institutionalized redlining by the Federal Housing Administration-include disparate present-day environmental health outcomes. Noise pollution is health-harming, but just one study has associated contemporary noise with redlining in some HOLC-mapped United States (US) cities, while two national studies found associations between greater neighborhood-level people of color composition and increased noise. No studies have examined noise pollution exposure disparities across all HOLC-mapped cities or based on the intersection of race/ethnicity and redlining.

OBJECTIVE

We address three objectives: (1) Assess disparities in fine-scale, per person transportation noise exposures by historical redlining status across all HOLC-mapped cities. (2) Quantify disparities in noise exposures by race/ethnicity nationwide. (3) Explore interactions between redlining status and race/ethnicity in noise exposures.

METHODS

We analyzed three data sources: (1) complete digital HOLC maps of ordered investment risk grades (A-D), (2) fine-scale (30 m) estimates of transportation noise levels (year-2020), and (3) sociodemographic characteristics of individuals in year-2020 census blocks.

RESULTS

We find an approximately monotonic association for excess transportation noise with HOLC grade, marked by a pronounced exposure increase (17.4 dBA or 3× loudness) between contemporary residents of grade A (highest-graded) and D (lowest-graded) neighborhoods, a pattern consistent across HOLC-mapped cities. People of color experience ~7 dBA greater (2× louder) excess transportation noise exposures than White people nationwide, a pattern consistent across US counties. Noise exposure disparities are larger by HOLC grade than by race/ethnicity. However, contemporary racial/ethnic noise exposure disparities persist within each HOLC grade at levels approximating those disparities existing in ungraded areas, indicating that historical redlining is one of multiple discriminatory practices shaping contemporary national soundscape injustices.

SIGNIFICANCE

Findings illustrate how historical redlining and broader racialized inequalities in US society have shaped environmental injustices nationwide.

IMPACT STATEMENT

Excessive noise exposures harm human health. Communities of color in the United States experience disparate noise exposures, although previous studies are limited by reliance upon aggregated data. They are also disproportionately concentrated in historically redlined areas. Legacies of redlining include persistent racial and economic inequalities and environmental health disparities. Here, we conduct the first complete national examination of contemporary noise pollution disparities with respect to historical redlining and race/ethnicity. Findings advance understanding of the historical roots and enduring salience of race-based disparities in noise pollution exposures and can inform efforts to address these disparities through noise pollution policy-making.

New York State Climate Impacts Assessment Chapter 07: Human Health and Safety

New Yorkers face a multitude of health and safety risks that are exacerbated by a changing climate. These risks include direct impacts from extreme weather events and other climate hazards, as well as indirect impacts occurring through a chain of interactions. Physical safety, physical health, and mental health are all part of the equation-as are the many nonclimate factors that interact with climate change to influence health outcomes. This chapter provides an updated assessment of all these topics at the intersection of climate change, public health and safety, and equity in the state of New York. Key findings are presented below.

SchoolHEAT: Racial and Ethnic Inequity in School Temperature

Exposure to high environmental temperature is detrimental to health through multiple pathways. This paper describes disparities in school-based high-temperature exposure at metropolitan schools in the United States. Using school location and sociodemographic data from the National Center for Education Statistics, neighborhood data from the US Census Bureau, and land surface temperature (LST) data from the Aqua Earth-observing satellite mission, we find that for every 10% more Black or Hispanic residents in the neighborhood, schools have LST 0.25 °C and 0.38 °C hotter, respectively. When the Black or Hispanic student population is greater than the neighborhood population, LST is an additional 0.20 °C and 0.40 °C for each 10% increase in students over neighborhood population, respectively. Black and Hispanic students are overrepresented in the hottest schools, making up 58.7% of students in the hottest 20% of schools, compared to only 30.0% of students in the coolest 20% of schools.

New York State Climate Impacts Assessment Chapter 01: Introduction

New York State's climate is changing. Temperatures are rising, precipitation is increasing, sea levels are rising, and extreme weather events are becoming more frequent and severe. Over time, these changes are projected to worsen. The New York State Climate Impacts Assessment provides a science-based analysis of what to expect from climate change in New York. Working with partners across the state, the team assembled to produce this assessment reviewed the latest science and modeling to project and characterize what New York State's climate is likely to look like in the future and how this will affect natural systems, society, and various sectors of the economy. The assessment will enable decision-makers at all levels-from individual residents, businesses, and landowners to municipal and state government agencies-to better understand and make informed choices about how to plan and prepare for climate change.

Summer Heat, Historic Redlining, and Neighborhood Walking among Older Adults: 2017 National Household Travel Survey

No known studies have examined the relationships between urban heat islands, historic redlining, and neighborhood walking in older adults. We assessed whether (1) individual and neighborhood characteristics (including redlining score) differ by neighborhood summer land surface temperature (LST); (2) higher LST is associated with less neighborhood walking, and whether associations differ by historic redlining score; and (3) neighborhoods with discriminatory redlining scores have greater LSTs. We used data on 3982 ≥ 65 years old from the 2017 National Household Travel Survey. Multivariable negative binomial and linear regressions tested associations between LST z-score (comparing participant's neighborhood LST to surrounding region's LST) and self-reported neighborhood walking and the association between living in neighborhoods redlined as "definitely declining" or "hazardous" (versus "still desirable"/"best") and LST z-score. LSTs were higher for those in neighborhoods with higher area deprivation scores and more African American/Black residents. Older adults living in neighborhoods with higher summer LST z-scores had fewer minutes of neighborhood walking/day. This association seemed limited to individuals with neighborhood redlining scores of "still desirable"/"best." Neighborhood redlining scores of "definitely declining" or "hazardous" (versus "still desirable" and "best") were associated with greater neighborhood summer LSTs. Overall, these findings suggest that historically redlined neighborhoods may experience urban heat island effects more often. While older adults living in hotter neighborhoods with "still desirable" or "best" redlining scores may less often engage in neighborhood walking, those in neighborhoods with redlining scores of "definitely declining" and "hazardous" do not seem to decrease neighborhood walking with higher LSTs. Future work is needed to elucidate the impact of extreme heat on health-promoting behaviors such as walking and the types of interventions that can successfully counteract negative impacts on historically disadvantaged communities.

Outdoor thermal performance of urban development patterns in Greater Adelaide since the late 19th century

Extreme heat events have become more common and more severe during summer than ever before as a result of the warming climate in Australia. The impact of urban morphology and green coverage on outdoor thermal comfort has been the subject of extensive research, however, their link to suburban developments of different historic periods is still underexplored. This paper investigates and compares the outdoor thermal performance of ten suburban areas constructed since the late nineteenth century in Greater Adelaide, which were built to different planning ideals and concepts of their time. Microclimate models of two precedents for five development eras were constructed in ENVI-met, validated with site data related to a recent heatwave event in 2023, and then used to facilitate further investigation of the impact of development patterns on outdoor thermal comfort. This study examines how these urban patterns perform in scenarios of varying development intensity and greenery ratio. In these case studies, the distance between buildings, streets' spatial ratio and green coverage has a significant impact on the thermal environment. The results underline the impact of solar exposure on outdoor thermal performance even in lower-density suburban areas. Some of the outcomes of the study are counter-intuitive to conventional assumptions about urban design typologies. In this comparison, for example, one of the "green" model garden city developments did not perform as well as denser 19th-century suburbs. The results can support better decision-making for future urban planning in Australia and other regions with similar climate conditions. The study shows that real performance does not always align with stated green ambitions and, urban design should consider and evaluate heat mitigation through evidence-based testing to achieve real green development.

The Legacy of Redlining: Increasing Childhood Asthma Disparities through Neighborhood Poverty

Rationale: Identifying the root causes of racial disparities in childhood asthma is critical for health equity. Objectives: To determine whether the racist policy of redlining in the 1930s led to present-day disparities in childhood asthma by increasing community-level poverty and decreasing neighborhood socioeconomic position (SEP). Methods: We categorized census tracts at the birth address of participants from the Children's Respiratory and Environmental Workgroup birth cohort consortium into categories A, B, C, and D as defined by the Home Owners Loan Corporation, with D being the highest perceived risk. Surrogates of present-day neighborhood-level SEP were determined for each tract, including the percentage of low-income households, the CDC's Social Vulnerability Index, and other tract-level variables. We performed causal mediation analysis, which, under the assumption of no unmeasured confounding, estimates the direct and mediated pathways by which redlining may cause asthma disparities through tract-level mediators adjusting for individual-level covariates. Measurements and Main Results: Of 4,849 children, the cumulative incidence of asthma through age 11 was 26.6%, and 13.2% resided in census tracts with a Home Owners Loan Corporation grade of D. In mediation analyses, residing in Grade-D tracts (adjusted odds ratio = 1.03 [95% confidence interval = 1.01, 1.05]) was significantly associated with childhood asthma, with 79% of this increased risk mediated by percentage of low-income households; results were similar for the Social Vulnerability Index and other tract-level variables. Conclusions: The historical structural racist policy of redlining led to present-day asthma disparities in part through decreased neighborhood SEP. Policies aimed at reversing the effects of structural racism should be considered to create more just, equitable, and healthy communities.

Air pollution exposure and head and neck cancer incidence

To investigate air pollution's effect in the form of PM2.5 (particulate matter measuring less than 2.5 microns) on head and neck aerodigestive cancer incidence, an epidemiological cohort analysis was performed using data from the Surveillance Epidemiology and End Results national cancer database from the years 2002-2012. The relationship between US county mean PM2.5 levels and head and neck cancer (HNC) incidence rates were examined using a linear mixed model. Lagged effect of the pollutant's effect on HNC incidence was analyzed. Our results showed a significant association between the incidence of HNC and certain subtypes with PM2.5 exposure after controlling for demographic characteristics, smoking and alcohol use. We observed the highest association at a 5-year lag period (β = 0.24, p value < 0.001). We observed significant associations at no lag (β = 0.16, p value = 0.02) and up to a 20-year lag period (β = 0.15, p value < 0.001). PM2.5 exposure is associated with an increased incidence of HNC, with the strongest association at a 5-year lag period. To better understand the relationships between exposure and cancer pathogenesis, further subgroup analysis is needed.

More extremely hot days, more heat exposure and fewer cooling options for people of color in Connecticut, U.S

It is well-documented that people of color in the U.S. are disproportionately exposed to extreme urban heat. However, most studies have focused on large cities for one point in time, and less is known about how heat exposure changes over time in smaller cities. Here, we present a study of the changing nature of urban heat exposure and cooling strategies for ten cities in Connecticut in the U.S. Our results show that people of color experience more heat exposure and fewer adaptation strategies. They experienced higher overall temperatures, more extremely hot days, and larger increases in heat exposure. Also, they have lower air conditioning ownership rates and lower tree cover. Taken together, the results indicate that people of color are not only exposed to higher temperatures but also disproportionately exposed to increasing temperatures over time. With lower heat adaptation capacity, people of color are more vulnerable to increasing urban heat.

Environmental justice of Texas recreational water quality - The disproportionate E. coli levels and trends

The presence of pathogens is one of the leading causes of stream water quality impairment in the US. Escherichia coli (E. coli) is a fecal pathogen indicator and also signals the presence of more pathogenic microbes. Although it is reported that Black, Indigenous, and communities of color suffer more from E. coli contamination, there is a lack of investigation of the potential inequality of E. coli contamination in recreational waterbodies, particularly regarding whether this inequality persists over the long term. Using E. coli monitoring data from 1,424 stations from 2001 to 2021 in Texas, we tested the research hypotheses of racial and economic inequalities in E. coli levels and trends with quantile regression and logistic regression approaches. We found that economic disparities had a more significant relationship with E. coli contamination in Texas recreational waterbodies than racial disparities after controlling for building age, land covers, imperviousness, and precipitation. The economic disparities in E. coli contamination were more prevalent after 2010 and in extreme E. coli levels. In addition, implementing watershed protection plans could mitigate the economic disparities associated with the rising trend of E. coli levels between 2001 and 2021. Findings from this research underscore clean surface water deprivation from underserved communities and call for inclusive watershed management strategies to address the water quality injustice.

Connecting Past to Present: Does Historical Redlining Affect Current Life Expectancy?

INTRODUCTION

Previous research has documented a strong relationship between currently living in the redlined zones of the 1930s and suffering from a higher prevalence of disease. However, little is known about the relationship between historical redlining, modern-day redlining, and current resident health outcomes. This paper aimed to simultaneously model the associations between both historical redlining and modern-day redlining on current health outcomes.

METHODS

In this paper, we used structural equation modeling to uncover relationships between current and historical redlining practices and modern-day life expectancy, exploring two levels of potential mediating factors: (1) racial segregation and structural racism; and (2) mediating health outcomes. We analyzed data from 11,661 census tracts throughout the United States using historical redlining data from 1940, modern redlining data from 2010 to 2017, racial segregation and structural racism indices from 2010 to 2019, health outcome data from 2021 to 2022, and life expectancy data from 2010 to 2015. Historical redlining was measured using Home Owners' Loan Corporation (HOLC) ratings, which ranged from 1.0 for favorable neighborhoods ("greenlined") to 4.0 for unfavorable ("redlined") neighborhoods. Modern-day redlining was measured using Home Mortgage Disclosure Act (HMDA) data, which were transformed into four quartiles, ranging from level 1 (low mortgage rejection rates) to level 4 (high mortgage rejection rates).

RESULTS

We found a significant relationship between historic redlining and current life expectancy, with average life expectancy decreasing steadily from 80.7 years in HOLC 1 tracts to 75.7 years in HOLC 4 tracts, a differential of 5.0 years between the greenlined and redlined tracts. We also found a significant relationship between modern-day redlining and current life expectancy, with average life expectancy decreasing steadily from 79.9 years in HMDA 1 tracts to 73.5 years in HMDA 4 tracts, a differential of 6.4 years. In the structural equation model, historical redlining had a total effect of decreasing life expectancy by 1.18 years for each increase of one in the HOLC rating. Modern-day redlining had a total effect of decreasing life expectancy by 1.89 years for each increase of one in the HMDA quartile.

CONCLUSION

This paper provides new evidence that the legacy of redlining is not relegated to the history books but rather is a present and pressing public health issue today.

Methodologic Strategies for Quantifying Associations of Historical and Contemporary Mortgage Discrimination on Population Health Equity: A Systematic Review

BACKGROUND

Mortgage discrimination refers to the systematic withholding of home mortgages from minoritized groups. In recent years, there has been an increase in empirical research investigating associations of historical and contemporary mortgage discrimination on contemporary  outcomes. Investigators have used a variety of measurement methods and approaches, which may have implications for results and interpretation.

PURPOSE

We conducted a systematic review of peer-reviewed literature that has quantified links between both historical and current mortgage discrimination with contemporary adverse environmental, social, and health outcomes. Our goals were to document the methodology used to measure and assign mortgage discrimination, to assess implications for results and interpretation, and to make recommendations for future work.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, literature searches were conducted in September 2022 using terms that combined concepts of mortgage discrimination, health, and neighborhood environment.

RESULTS

In total, 45 papers fit the eligibility criteria. In these, researchers investigated associations between mortgage discrimination and: (1) health outcomes (N = 28); (2) environmental and social exposures including heat, air pollution, greenspace, soil lead levels, and crime (N = 12); and (3) built environment features, including presence of retail alcohol, fast food, and tobacco stores (N = 5). Eleven included studies used Home Mortgage Discrimination Act (HMDA) data to identify racialized bias in mortgage discrimination or redlining, and 34 used Homeowner Loan Corporation (HOLC) maps. The construction and parametrization of mortgage discrimination or redlining and the spatial assignment of HOLC grades to contemporary addresses or neighborhoods varied substantially across studies.

CONCLUSIONS

Results from our review suggest the need for careful consideration of optimal methods to analyze mortgage discrimination such as HOLC spatial assignment or HMDA index parametrization, contemplation of covariates, and place-based knowledge of the study location.

NPCC4: New York City climate risk information 2022-observations and projections

New York City (NYC) faces many challenges in the coming decades due to climate change and its interactions with social vulnerabilities and uneven urban development patterns and processes. This New York City Panel on Climate Change (NPCC) report contributes to the Panel's mandate to advise the city on climate change and provide timely climate risk information that can inform flexible and equitable adaptation pathways that enhance resilience to climate change. This report presents up-to-date scientific information as well as updated sea level rise projections of record. We also present a new methodology related to climate extremes and describe new methods for developing the next generation of climate projections for the New York metropolitan region. Future work by the Panel should compare the temperature and precipitation projections presented in this report with a subset of models to determine the potential impact and relevance of the "hot model" problem. NPCC4 expects to establish new projections-of-record for precipitation and temperature in 2024 based on this comparison and additional analysis. Nevertheless, the temperature and precipitation projections presented in this report may be useful for NYC stakeholders in the interim as they rely on the newest generation of global climate models.

NPCC4: Tail risk, climate drivers of extreme heat, and new methods for extreme event projections

We summarize historic New York City (NYC) climate change trends and provide the latest scientific analyses on projected future changes based on a range of global greenhouse gas emissions scenarios. Building on previous NPCC assessment reports, we describe new methods used to develop the projections of record for sea level rise, temperature, and precipitation for NYC, across multiple emissions pathways and analyze the issue of the "hot models" associated with the 6th phase of the Coupled Model Intercomparison Project (CMIP6) and their potential impact on NYC's climate projections. We describe the state of the science on temperature variability within NYC and explain both the large-scale and regional dynamics that lead to extreme heat events, as well as the local physical drivers that lead to inequitable distributions of exposure to extreme heat. We identify three areas of tail risk and potential for its mischaracterization, including the physical processes of extreme events and the effects of a changing climate. Finally, we review opportunities for future research, with a focus on the hot model problem and the intersection of spatial resolution of projections with gaps in knowledge in the impacts of the climate signal on intraurban heat and heat exposure.

NPCC4: Climate change and New York City's health risk

This chapter of the New York City Panel on Climate Change 4 (NPCC4) report considers climate health risks, vulnerabilities, and resilience strategies in New York City's unique urban context. It updates evidence since the last health assessment in 2015 as part of NPCC2 and addresses climate health risks and vulnerabilities that have emerged as especially salient to NYC since 2015. Climate health risks from heat and flooding are emphasized. In addition, other climate-sensitive exposures harmful to human health are considered, including outdoor and indoor air pollution, including aeroallergens; insect vectors of human illness; waterborne infectious and chemical contaminants; and compounding of climate health risks with other public health emergencies, such as the COVID-19 pandemic. Evidence-informed strategies for reducing future climate risks to health are considered.

NPCC4: Advancing climate justice in climate adaptation strategies for New York City

The Advancing Climate Justice in Climate Adaptation Strategies for New York City (Equity) chapter of NPCC4 builds on the findings and recommendations from NPCC3 to identify additional metrics and adaptation efforts that can advance climate justice. First, the chapter assesses the efforts of the City to incorporate equity into climate adaptation efforts since NPCC3 and describes how the communities profiled in NPCC3 have implemented and evolved their approaches to addressing the intersecting climate, environmental, and social stressors that they continue to face. Second, it adds to the historical context of climate inequity by linking the bioregion's history of colonization, land dispossession, and slavery building on emerging evidence demonstrating how historical and contemporary land use patterns and decisions shape present and future climate risks and social vulnerability, including climate displacement. Third, it recommends a NYC-focused metric to identify areas of the city that are most vulnerable to the intersection of climate hazards, social vulnerability, and displacement. Finally, it highlights approaches to more equitable and just climate adaptation drawn from local, national, and international examples. As such, the chapter offers best practices that prioritize community-driven climate resilience approaches that are integrated, more equitable, and racially just.

Using geographic effect measure modification to examine socioeconomic-related surface temperature disparities in New York City

BACKGROUND

Lower socioeconomic (SES) communities are more likely to be situated in urban heat islands and have higher heat exposures than their higher SES counterparts, and this inequality is expected to intensify due to climate change.

OBJECTIVES

To examine the relationship between surface temperatures and SES in New York City (NYC) by employing a novel analytical approach. Through incorporating modifiable features, this study aims to identify potential locations where mitigation interventions can be implemented to reduce heat disparities associated with SES.

METHODS

Using the 2013-2017 American Community Survey, U.S Landsat-8 Analysis Ready Data surface temperatures (measured on 8/12/2016), and the NYC Land Cover Dataset at the census tract level (2098 tracts), this study examines the association between two components of tract-level SES (percentage of individuals living below the poverty line and the percentage of individuals without a high school degree) and summer day surface temperature in NYC. First, we examine this association with an unrestricted NYC linear regression, examining the city-wide association between the two SES facets and summer surface temperature, with additional models adjusting for altitude, shoreline, and nature-cover. Then, we assess geographic effect measure modification by employing the same models to three supplemental regression model strategies (borough-restricted and community district-restricted linear regressions, and geographically weighted regression (GWR)) that examined associations within smaller intra-city areas.

RESULTS

All regression strategies identified areas where lower neighborhood SES composition is associated with higher summer day surface temperatures. The unrestricted NYC regressions revealed widespread disparities, while the borough-restricted and community district-restricted regressions identified specific political boundaries within which these disparities existed. The GWR, addressing spatial autocorrelation, identified significant socioeconomic heat disparities in locations such as northwest Bronx, central Brooklyn, and uptown Manhattan. These findings underscore the need for targeted policies and community interventions, including equitable urban planning and cooling strategies, to mitigate heat exposure in vulnerable neighborhoods.

IMPACT STATEMENT

This study redefines previous research on urban socioeconomic disparities in heat exposure by investigating both modifiable (nature cover) and non-modifiable (altitude and shoreline) built environment factors affecting local temperatures at the census tract level in New York City. Through a novel analytical approach, the research aims to highlight intervention opportunities to mitigate heat disparities related to socioeconomic status. By examining the association between surface temperatures and socioeconomic status, as well as investigating different geographic and governmental scales, this study offers actionable insights for policymakers and community members to address heat exposure inequalities effectively across different administrative boundaries. The objective is to pinpoint potential sites for reducing socioeconomic heat exposure disparities at various geographic and political levels.

Residential segregation and summertime air temperature across 13 northeastern U.S. states: Potential implications for energy burden

High ambient summertime temperatures are an increasing health concern with climate change. This is a particular concern for minoritized households in the United States, for which differential energy burden may compromise adaptive capacity to high temperatures. Our research question was: Do minoritized groups experience hotter summers than the area average, and do non-Hispanic white people experience cooler summers? Using a fine-scaled spatiotemporal air temperature model and U.S. census data, we examined local (within-county) differences in warm season cooling degree days (CDDs) by ethnoracial group as a proxy for local energy demand for space cooling across states of the northeast and mid-Atlantic U.S. in 2003-2019. Using state-specific regression models adjusted for year and county, we found that Black and Latino people consistently experienced more CDDs, non-Hispanic white people experienced fewer CDDs, and Asian populations showed mixed results. We also explored a concentration-based measure of residential segregation for each ethnoracial group as one possible pathway towards temperature disparities. We included the segregation measure as a smooth term in a regression model adjusted for county and year. The results were nonlinear, but higher concentrations of white people were associated with lower annual CDDs and higher concentrations of Latino people were associated with higher annual CDDs than the county average. Concentrations for Black and Asian people were nonmonotonic, sometimes with bowed associations. These findings suggest that present-day residential segregation, as modeled by spatially smoothed ethnoracial subgroup concentrations, may contribute to summertime air temperature disparities and influence adaptive capacity. We hope these findings can support place-based interventions, including targeting of energy insecurity relief programs.

Traces of Historical Redlining in the Contemporary United States: New Evidence from the Add Health Cohort

Research on the legacies of historical redlining has lacked nationally representative and multilevel data. We advance this literature by analyzing new data that links historical redlining maps to the residential addresses of participants in the National Longitudinal Study of Adolescent to Adult Health (Add Health), a diverse and national cohort of adolescents who transitioned to adulthood between the mid-1990s and late 2010s (N=10,897). We report three key findings. First, while most participants did not live within the boundaries of historical redlining maps, Black (22%) and Hispanic (28%) participants were several times more likely than their White peers (8%) to live in either a formerly yellow- or red-lined urban area in adolescence. Second, adolescents who resided in yellow- or red-lined areas also tended to live in the most disadvantaged households and neighborhoods and attained the lowest levels of socioeconomic status in adulthood. Third, Black and White adolescents who lived in rural areas also experienced similar or worse adult outcomes than their peers who lived in redlined urban areas. We also find anomalous but inconclusive patterns for the small group of Black and Hispanic participants who lived in historically affluent "green-lined" areas in adolescence, including poor adult health and high risk of contact with the criminal justice system. Given these findings, we outline avenues for future research that could include historical redlining maps, but also expand beyond urban redlining to consider nonmetropolitan areas and other contemporary indicators of structural racism.

Increasing tree cover and high-albedo surfaces reduces heat-related ER visits in Los Angeles, CA

There is an urgent need for strategies to reduce the negative impacts of a warming climate on human health. Cooling urban neighborhoods by planting trees and vegetation and increasing albedo of roofs, pavements, and walls can mitigate urban heat. We used synoptic climatology to examine how different tree cover and albedo scenarios would affect heat-related morbidity in Los Angeles, CA, USA, as measured by emergency room (ER) visits. We classified daily meteorological data for historical summer heat events into discrete air mass types. We analyzed those classifications against historical ER visit data to determine both heat-related and excess morbidity. We used the Weather Research and Forecasting model to examine the impacts of varied tree cover and albedo scenarios on meteorological outcomes and used these results with standardized morbidity data algorithms to estimate potential reductions in ER visits. We tested three urban modification scenarios of low, medium, and high increases of tree cover and albedo and compared these against baseline conditions. We found that avoiding 25% to 50% of ER visits during heat events would be a common outcome if the urban environment had more tree cover and higher albedo, with the greatest benefits occurring under heat events that are moderate and those that are particularly hot and dry. We conducted these analyses at the county level and compared results to a heat-vulnerable, working-class Los Angeles community with a high concentration of people of color, and found that reductions in the rate of ER visits would be even greater at the community level compared to the county.

Racial/ethnic disparities in the distribution of heatwave frequency and expected economic losses in the US

Previous research on social disparities in heat exposure has not examined heatwave frequency or economic damage at the local or neighborhood level. Additionally, most US studies have focused on specific cities or regions, and few national-scale studies encompassing both urban and rural areas have been conducted. These gaps are addressed here by analyzing racial/ethnic disparities in the distribution of annual heatwave frequency and expected economic losses from heatwave occurrence in the contiguous US. Census tract-level data on annualized heatwave frequency and expected loss from the FEMA's National Risk Index are linked to relevant variables from the American Community Survey. Results indicate that all racial/ethnic minority groups except non-Hispanic Black are significantly overrepresented in neighborhoods with greater annual heatwave frequency (top 10% nationally), and all minority groups are overrepresented in neighborhoods with greater total expected annual loss from heatwaves, compared to non-Hispanic Whites. Multivariable models that control for spatial clustering, climate zone, and relevant socio-demographic factors reveal similar racial/ethnic disparities, and suggest significantly greater heatwave frequency and economic losses in neighborhoods with higher percentages of Hispanics and American Indians. These findings represent an important starting point for more detailed investigations on the adverse impacts of heatwaves for US minority populations and formulating appropriate policy interventions.

Differential effects of air pollution exposure on mental health: Historical redlining in New York State

Growing evidence suggests that ambient air pollution has adverse effects on mental health, yet our understanding of its unequal impact remains limited, especially in areas with historical redlining practices. This study investigates whether the impact of daily fluctuations in ambient air pollutant levels on emergency room (ER) visits for mental disorders (MDs) varies across neighborhoods affected by redlining. Furthermore, we explored how demographic characteristics and ambient temperature may modify the effects of air pollution. To assess the disproportional short-term effects of PM2.5, NO2, and O3 on ER visits across redlining neighborhoods, we used a symmetric bidirectional case-crossover design with a conditional logistic regression model. We analyzed data from 2 million ER visits for MDs between 2005 and 2016 across 17 cities in New York State, where redlining policies were historically implemented. A stratified analysis was performed to examine potential effect modification by individuals' demographic characteristics (sex, age, and race/ethnicity) and ambient temperature. We found that both PM2.5 and NO2 were significantly associated with MD-related ER visits primarily in redlined neighborhoods. Per 10μgm-3 increase in daily PM2.5 and per 10 ppb increase in NO2 concentration were associated with 1.04 % (95 % Confidence Interval (CI): 0.57 %, 1.50 %) and 0.44 % (95 % CI: 0.21 %, 0.67 %) increase in MD-related ER visits in redlined neighborhoods, respectively. We also found significantly greater susceptibility among younger persons (below 18 years old) and adults aged 35-64 among residents in grade C or D, but not in A or B. Furthermore, we found that positive and statistically significant associations between increases in air pollutants (PM2.5 and NO2) and MD-related ER visits exist during medium temperatures (4.90 °C to 21.11 °C), but not in low or high temperature. Exposures to both PM2.5 and NO2 were significantly associated with MD-related ER visits, but these adverse effects were disproportionately pronounced in redlined neighborhoods.

Research to Confront Climate Change Complexity: Intersectionality, Integration, and Innovative Governance

Climate impacts increasingly unfold in interlinked systems of people, nature, and infrastructure. The cascading consequences are revealing sometimes surprising connections across sectors and regions, and prospects for climate responses also depend on complex, difficult-to-understand interactions. In this commentary, we build on the innovations of the United States Fifth National Climate Assessment to suggest a framework for understanding and responding to complex climate challenges. This approach involves: (a) integration of disciplines and expertise to understand how intersectionality shapes complex climate impacts and the wide-ranging effects of climate responses, (b) collaborations among diverse knowledge holders to improve responses and better encompass intersectionality, and (c) sustained experimentation with and learning about governance approaches capable of handling the complexity of climate change. Together, these three pillars underscore that usability of climate-relevant knowledge requires transdisciplinary coordination of research and practice. We outline actionable steps for climate research to incorporate intersectionality, integration, and innovative governance, as is increasingly necessary for confronting climate complexity and sustaining equitable, ideally vibrant climate futures.

Indoor overheating: A review of vulnerabilities, causes, and strategies to prevent adverse human health outcomes during extreme heat events

The likelihood of exposure to overheated indoor environments is increasing as climate change is exacerbating the frequency and severity of hot weather and extreme heat events (EHE). Consequently, vulnerable populations will face serious health risks from indoor overheating. While the relationship between EHE and human health has been assessed in relation to outdoor temperature, indoor temperature patterns can vary markedly from those measured outside. This is because the built environment and building characteristics can act as an important modifier of indoor temperatures. In this narrative review, we examine the physiological and behavioral determinants that influence a person's susceptibility to indoor overheating. Further, we explore how the built environment, neighborhood-level factors, and building characteristics can impact exposure to excess heat and we overview how strategies to mitigate building overheating can help reduce heat-related mortality in heat-vulnerable occupants. Finally, we discuss the effectiveness of commonly recommended personal cooling strategies that aim to mitigate dangerous increases in physiological strain during exposure to high indoor temperatures during hot weather or an EHE. As global temperatures continue to rise, the need for a research agenda specifically directed at reducing the likelihood and impact of indoor overheating on human health is paramount. This includes conducting EHE simulation studies to support the development of consensus-based heat mitigation solutions and public health messaging that provides equitable protection to heat-vulnerable people exposed to high indoor temperatures.

A greening theory of change: How neighborhood greening impacts adolescent health disparities

Neighborhoods are one of the key determinants of health disparities among young people in the United States. While neighborhood deprivation can exacerbate health disparities, amenities such as quality parks and greenspace can support adolescent health. Existing conceptual frameworks of greening-health largely focus on greenspace exposures, rather than greening interventions. In this paper, we develop and propose a Greening Theory of Change that explains how greening initiatives might affect adolescent health in deprived neighborhoods. The theory situates greening activities and possible mechanisms of change in the context of their ability to modify distal social determinants of health factors, stemming from macrostructural and historical processes that lead to resource inequalities, affecting both the social and built environment in which adolescents live and develop. The framework illustrates both short- and long-term health, economic, and security effects of greening. We also describe how the theory informed the development of Project VITAL (Vacant lot Improvement to Transform Adolescent Lives) in Baltimore, MD, which aims to (1) build a citywide sharable database on vacant lot restoration activities, (2) evaluate the impact of greening initiatives on adolescent health outcomes, (3) conduct cost-effectiveness analyses, and (4) develop best practices for greening programs for improved adolescent health.

Examining racial and ethnic heat exposure disparities in New York City (NYC) across different spatial and political scales through geographic effect measure modification

Structural racism in the United States has resulted in neighborhoods with higher proportions of non-Hispanic Black (Black) or Hispanic/Latine residents having more features that intensify, and less that cool, the local-heat environment. This study identifies areas of New York City (NYC) where racial/ethnic heat exposure disparities are concentrated. We analyzed data from the 2013-2017 American Community Survey, U.S Landsat-8 Analysis Ready Data on summer surface temperatures, and NYC Land Cover Dataset at the census tract-level (n = 2098). Four cross-sectional regression modeling strategies were used to estimate the overall City-wide association, and associations across smaller intra-city areas, between tract-level percent of Black and percent Hispanic/Latine residents and summer day surface temperature, adjusting for altitude, shoreline, and nature-cover: overall NYC linear, borough-specific linear, Community District-specific linear, and geographically weighted regression models. All three linear regressions identified associations between neighborhood racial and ethnic composition and summer day surface temperatures. The geographically weighted regression models, which address the issue of spatial autocorrelation, identified specific locations (such as northwest Bronx, central Brooklyn, and uptown Manhattan) within which racial and ethnic disparities for heat exposures are concentrated. Through examining the overall effects and geographic effect measure modification across spatial scales, the results of this study identify specific geographic areas for intervention to mitigate heat exposure disparities experienced by Black and Hispanic/Latine NYC residents.

A Heat Emergency: Urban Heat Exposure and Access to Refuge in Richmond, VA

The urban heat island effect exacerbates independent climate change-induced shifts toward longer, stronger, and more frequent heat extremes. Environmental inequity, driven by a history of racially motivated urban planning policies, has led particular demographics to bear the worst impacts of urban heat exposure and thus also climate change. These impacts cause adverse health outcomes in the form of heat emergencies. Through a novel demographic and spatial analysis of heat-related illness Emergency Medical Services data from Richmond, Virginia, this study investigates the relationships between heat health emergencies and intra-urban heat islands quantified through three heat exposure metrics. We also evaluate the accessibility of built refuge from urban heat in the form of public transit infrastructure, libraries, and government cooling centers in relation to these emergencies. We found that heat emergencies are inequitably distributed among racial, age, and socioeconomic groups in Richmond, particularly among residents identified as Male, Black or African American, 50+ years old, and experiencing mental health, intoxication, and/or homelessness. We found significant associations between the location of these heat emergencies and urban heat islands as estimated from remotely-sensed surface and community science-derived air temperature metrics, but not a co-estimated heat index. We also found that available refuge facilities are insufficiently located to protect individuals with reduced mobility across areas with the highest number of heat-related health emergencies. Community involvement in the mitigation and management of extreme heat threats, especially for those disproportionately impacted, is necessary to decrease the number of summertime heat illnesses.

Associations of Historical Redlining With BMI and Waist Circumference in Coronary Artery Risk Development in Young Adults

Introduction

Historical maps of racialized evaluation of mortgage lending risk (i.e., redlined neighborhoods) have been linked to adverse health outcomes. Little research has examined whether living in historically redlined neighborhoods is associated with obesity, differentially by race or gender.

Methods

This is a cross-sectional study to examine whether living in historically redlined neighborhoods is associated with BMI and waist circumference among Black and White adults in 1985-1986. Participants' addresses were linked to the 1930s Home Owners' Loan Corporation maps that evaluated mortgage lending risk across neighborhoods. The authors used multilevel linear regression models clustered on Census tract, adjusted for confounders to estimate main effects, and stratified, and interaction models by (1) race, (2) gender, and (3) race by gender with redlining differentially for Black versus White adults and men versus women. To better understand strata differences, they compared Census tract-level median household income across race and gender groups within Home Owners' Loan Corporation grade.

Results

Black adults (n=2,103) were more likely than White adults (n=1,767) to live in historically rated hazardous areas and to have higher BMI and waist circumference. Redlining and race and redlining and gender interactions for BMI and waist circumference were statistically significant (p<0.10). However, in stratified analyses, the only statistically significant associations were among White participants. White participants living in historically rated hazardous areas had lower BMI (β = - 0.63 [95% CI= -1.11, -0.15]) and lower waist circumference (β = - 1.50 [95% CI= -2.62, -0.38]) than those living in declining areas. Within each Home Owners' Loan Corporation grade, residents in White participants' neighborhoods had higher incomes than those living in Black participants' neighborhoods (p<0.0001). The difference was largest within historically redlined areas. Covariate associations differed for men, women, Black, and White adults, explaining the difference between the interaction and the stratified models. Race by redlining interaction did not vary by gender.

Conclusions

White adults may have benefitted from historical redlining, which may have reinforced neighborhood processes that generated racial inequality in BMI and waist circumference 50 years later.

Linking environmental injustices in Detroit, MI to institutional racial segregation through historical federal redlining

OBJECTIVES

To identify the most pervasive environmental exposures driving environmental disparities today associated with historical redlining in Detroit.

METHODS

We overlaid Detroit's 1939 Home Owners' Loan Corporation (HOLC) shapefile from the Mapping Inequality project onto the EPA EJScreen and the DOT National Transportation Noise maps to analyze differences in current demographic and environmental indicators between historically redlined (D-grade) and non-redlined neighborhoods using simple linear regression and a boosted classification tree algorithm.

RESULTS

Historically redlined neighborhoods in Detroit experienced significantly higher environmental hazards than non-redlined neighborhoods in the form of 12.1% (95% CI: 7.2-17.1%) higher levels of diesel particulate matter (PM), 32.2% (95% CI: 3.3-69.3%) larger traffic volumes, and 65.7% (95% CI: 8.6-152.8%) higher exposure to hazardous road noise (LEQ(24h) >70 dBA). Historically redlined neighborhoods were situated near 1.7-times (95% CI: 1.4-2.1) more hazardous waste sites and twice as many (95% CI: 1.5-2.7) risk management plan (RMP) sites than non-redlined neighborhoods. The lifetime cancer risk from inhalation of air toxics was 4.4% (95% CI: 2.9-6.6%) higher in historically redlined communities, and the risk of adverse respiratory health outcomes from air toxics was 3.9% (95% CI: 2.1-5.6%) higher. All factors considered together, among the environmental hazards considered, the most pervasive hazards in historically redlined communities are proximity to RMP sites, hazardous road noise, diesel PM, and cancer risk from air pollution.

CONCLUSIONS

Historically redlined neighborhoods may have a disproportionately higher risk of developing cancer and adverse respiratory health outcomes from air toxics. Policies targeting air and noise pollution from transportation sources, particularly from sources of diesel exhaust, in historically redlined neighborhoods may ameliorate some of the impacts of structural environmental racism from historical redlining in Detroit.

Mobilizing knowledge about urban change for equity and sustainability: developing 'Change Stories', a multi-country transdisciplinary study

Background

Health-focused research funders increasingly support multi-country research partnerships that study health, urban development and equity in global settings. To develop new knowledge that benefits society, these grants require researchers to integrate diverse knowledges and data, and to manage research-related aspects of coloniality, such as power imbalances and epistemic injustices. We conducted research to develop a transdisciplinary study proposal with partners in multiple middle and high income countries, aiming to embed equity into the methodology and funding model.

Methods

Parallel to literature review, we used participatory and social research methods to identify case study cities for our primary study and to inform our study design. We conducted semi-structured interviews with informed and consented sustainable urban development experts in the USA (n=23). We co-developed our research approach with our global advisory group (n=14) and conducted a participatory workshop (n=30) to identify case study sites, also informed by conversations with international academic experts in sustainable development (n=27).

Results

Through literature review we found that there is a need to study the contextual pre-conditions of urban transformation, the influence of coloniality on understandings of how cities can change and the failure of standard development practices to meet the needs of all residents and the planet. Through expert input and literature we found that decolonial and storytelling methods may help us show the complexities behind stories of urban transformation, particularly the role of marginalized populations in creating long-term change.

Conclusions

There are multiple benefits of conducting research to develop an equitably designed multi-country research collaboration. We built new partnerships and co-developed our research approach, creating new understanding of diverse collaborators' disciplinary perspectives and institutional requirements. By investigating the informational needs of U.S. sustainable development actors and designing our study to meet these needs, we have increased the likelihood that our research will create impact.

"Death Is a Possibility for Those without Shelter": A Thematic Analysis of News Coverage on Homelessness and the 2021 Heat Dome in Canada

Among the most vulnerable to the health-harming effects of heat are people experiencing homelessness. However, during the 2021 Heat Dome, the deadliest extreme heat event (EHE) recorded in Canada to date, people experiencing homelessness represented the smallest proportion of decedents (n = 3, 0.5%)-despite the impacted region (British Columbia) having some of the highest rates of homelessness in the country. Thus, we sought to explore the 2021 Heat Dome as a media-based case study to identify potential actions or targeted strategies that were initiated by community support agencies, individuals and groups, and communicated in the news during this EHE that may have aided in the protection of this group or helped minimize the mortality impacts. Using media articles collated for a more extensive investigation into the effects of the 2021 Heat Dome (n = 2909), we identified a subset which included content on people experiencing homelessness in Canada (n = 274, 9%). These articles were thematically analysed using NVivo. Three main themes were identified: (i) public warnings issued during the 2021 Heat Dome directly addressed people experiencing homelessness, (ii) community support services explicitly targeting this population were activated during the heat event, and (iii) challenges and barriers faced by people experiencing homelessness during extreme heat were communicated. These findings suggest that mass-media messaging and dedicated on-the-ground initiatives led by various organizations explicitly initiated to support individuals experiencing homelessness during the 2021 Heat Dome may have assisted in limiting the harmful impacts of the heat on this community.

Climate Change and Children's Health: Building a Healthy Future for Every Child

The warming of our planet matters to every child. Driven by fossil fuel-generated greenhouse gas emissions, climate conditions stable since the founding of modern pediatrics in the mid-nineteenth century have shifted, and old certainties are falling away. Children's physical and mental health are threatened by climate change through its effects on temperature, precipitation, and extreme weather; ecological disruption; and community disruption. These impacts expose and amplify existing inequities and create unprecedented intergenerational injustice. Fossil fuel extraction and combustion cause harm today and reach centuries into the future, jeopardizing the health, safety, and prosperity of today's children and future generations. Appreciating the unique vulnerability of their patients, pediatricians have become leading health advocates for climate actions necessary to protect all living and future children. Policies that reduce reliance on fossil fuels and promote cleaner air, facilitate walking and bicycling, encourage more sustainable diets, increase access to nature, and develop more connected communities lead to immediate gains in child health and equity, and build a foundation for generations of children to thrive.

Extreme Heat Vulnerability Among Older Adults: A Multilevel Risk Index for Portland, Oregon

BACKGROUND AND OBJECTIVES

Extreme heat is an environmental health equity concern disproportionately affecting low-income older adults and people of color. Exposure factors, such as living in rental housing and lack of air conditioning, and sensitivity factors, such as chronic disease and social isolation, increase mortality risk among older adults. Older persons face multiple barriers to adaptive heat mitigation, particularly those living in historically temperate climates. This study measures two heat vulnerability indices to identify areas and individuals most vulnerable to extreme heat and discusses opportunities to mitigate vulnerability among older adults.

RESEARCH DESIGN AND METHODS

We constructed two heat vulnerability indices for the Portland, OR, metropolitan area: one using area scale proxy measures extracted from existing regional data and another at the individual scale using survey data collected following the 2021 Pacific Northwest Heat Dome event. These indices were analyzed using principal component analysis and Geographic Information Systems.

RESULTS

Results indicate that the spatial distribution of areas and individuals vulnerable to extreme heat are quite different. The only area found among the most vulnerable on both indices has the largest agglomeration of age- and income-restricted rental housing in the metropolitan area.

DISCUSSION AND IMPLICATIONS

Due to spatial variations in heat-related risk at the individual and area scales, measures addressing heat risk should not be spatially uniform. By focusing resources on older adult individuals and areas in particular need of assistance, heat risk management policies can be both highly efficient and cost effective.