Exploring the nexus of urban form, transport, environment and health in large-scale urban studies: A state-of-the-art scoping review.

BACKGROUND: As the world becomes increasingly urbanised, there is recognition that public and planetary health relies upon a ubiquitous transition to sustainable cities. Disentanglement of the complex pathways of urban design, environmental exposures, and health, and the magnitude of these associations, remains a challenge. A state-of-the-art account of large-scale urban health studies is required to shape future research priorities and equity- and evidence-informed policies. OBJECTIVES: The purpose of this review was to synthesise evidence from large-scale urban studies focused on the interaction between urban form, transport, environmental exposures, and health. This review sought to determine common methodologies applied, limitations, and future opportunities for improved research practice. METHODS: Based on a literature search, 2958 articles were reviewed that covered three themes of: urban form; urban environmental health; and urban indicators. Studies were prioritised for inclusion that analysed at least 90 cities to ensure broad geographic representation and generalisability. Of the initially identified studies, following expert consultation and exclusion criteria, 66 were included. RESULTS: The complexity of the urban ecosystem on health was evidenced from the context dependent effects of urban form variables on environmental exposures and health. Compact city designs were generally advantageous for reducing harmful environmental exposure and promoting health, with some exceptions. Methodological heterogeneity was indicative of key urban research challenges; notable limitations included exposure and health data at varied spatial scales and resolutions, limited availability of local-level sociodemographic data, and the lack of consensus on robust methodologies that encompass best research practice. CONCLUSION: Future urban environmental health research for evidence-informed urban planning and policies requires a multi-faceted approach. Advances in geospatial and AI-driven techniques and urban indicators offer promising developments; however, there remains a wider call for increased data availability at local-levels, transparent and robust methodologies of large-scale urban studies, and greater exploration of urban health vulnerabilities and inequities.

Understanding perceived park access and physical activity among older adults: A structural equation modeling approach.

Parks can provide a low-cost setting for safe physical activity, but older adults are underrepresented among park users in the United States. Using data from a population-representative survey in 2015 and 2018 among adults aged 60 years and older living in Philadelphia, we tested whether perceived access was a mechanism by which objectively-measured park access predicted self-reported physical activity. After controlling for individual-level factors and neighborhood characteristics, we found a statistically significant pathway from overall park area and within-park tree canopy to increased physical activity, mediated by perceived park access. These results highlight the importance of tree canopy for older adult park access and physical activity.

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.

Associations between land bank ownership and stewardship of vacant properties and crime, violence, and youth victimization in Flint, MI.

Land banks across the United States are managing expanding vacant property inventories. By maintaining vacant properties and engaging residents in the process, land banks facilitate processes integral to building safe neighborhoods and may play a role in violence prevention. Using generalized additive mixed model regression, adjusted for spatial and temporal dependencies, we examined whether land bank ownership and stewardship of vacant properties in Flint, Michigan were associated with trends in serious, violent, and firearm-involved crime, between 2015 and 2018. We tested for differences in trends in crime density between properties owned by the Genesee County Land Bank Authority (GCLBA; n = 7151) and comparison properties not owned by the land bank (n = 6,245). In addition, we tested for differences in crime density trends between vacant properties that received different levels of land bank stewardship, including biannual mowing, GCLBA standard stewardship, and GCLBA-sponsored community-engaged stewardship. We found that GCLBA ownership was associated with net declines in densities of all types of crime and violence, over time, relative to properties not owned by the GCLBA. When we distinguished between levels of stewardship, we found that GCLBA stewardship, both with and without community engagement, was associated with net declines in serious and violent crime relative to comparison properties. Only community-engaged GCLBA stewardship was associated with declines in firearm-involved crime and firearm-involved crime with a youth victim over time, relative to comparison properties. Land bank stewardship of vacant properties may be protective against crime, violence, and youth victimization in legacy cities like Flint, MI that experience high rates of vacant properties and violent crime.

Community identified characteristics related to illegal dumping; a mixed methods study to inform prevention.

Illegal dumping is a public health burden for communities suffering from historical disinvestment. We conducted a mixed methods study to answer: 1) What are stakeholder perspectives on social/environmental determinants of illegal dumping? and 2) Do these or other characteristics predict known locations of illegal dumping? We employed an exploratory sequential design in which we collected and analyzed in-depth interviews (n=12) with service providers and residents and subsequently collected and analyzed data from multiple secondary sources. Stakeholders endorsed nine determinants of illegal dumping: Economic Decline, Scale of Vacancy, Lack of Monitoring, Poor Visibility, Physical Disorder, Illegal Activity, Norms, Accessibility, and Seclusion. Results demonstrate important community-identified, modifiable, social, and environmental characteristics related to illegal dumping with the potential to inform effective prevention.

Does Urban Greenspace Reduce Mortality Inequalities Based on Poverty, Race, or Both in Philadelphia, PA?

While past research suggests that urban greenspace is associated with weaker income-based mortality inequities, little is known about associations with racial inequities, which may be distinct owing to historical and contemporary forms of racism. We quantified the extent to which different measures of greenspace modified socioeconomic and racial/ethnic inequities in all-cause and cardiovascular disease mortality. For every residential census tract in Philadelphia, PA (N = 376), we linked counts of all-cause and cardiovascular mortality (years 2008-2015) with measures of greenspace (proportion tree canopy or grass/shrub cover, proportion residents reporting park access, and the normalized difference vegetation index measure of overall greenness) and American Community Survey-based measures of sociodemographic composition (proportion of residents living in poverty, proportion identifying as non-Hispanic Black, and the index of concentration at the extremes (ICE) representing racialized economic deprivation). We used age- and sex-adjusted negative binomial models, with the natural logarithm of age-specific population counts as an offset, to quantify the magnitude of inequities by each composition variable, overall and stratified by categories of each greenspace measure. Inequities in mortality were weaker among neighborhoods with higher proportion grass/shrub cover or overall greenness. The most substantially narrowed inequities were those by the ICE. Mortality inequities did not differ substantially by perceived park access, and tree canopy was associated with weaker ICE-based inequities only. In this ecologic analysis, neighborhood greenspace was associated with weaker mortality inequities. However, associations varied across greenspace type and sociodemographic composition metrics, with generally stronger associations with overall greenness and grass/shrub coverage, and for ICE-basedinequities.

Lessons learned from local vacant land management organizations for engaging youth in greening.

Youth living in areas with high concentrations of vacant properties may be at particular risk for poor health outcomes given the associations between deteriorated vacant properties, poor mental health, and community violence. Vacant lot greening has emerged as a key strategy to mitigate the harms of deteriorated properties. Youth engagement in greening has documented benefits for youth, yet few organizations responsible for managing vacant properties currently engage youth. Further, few researchers have examined the best practices that organizations can employ to effectively engage youth in greening programs. The purpose of this study was to understand how high functioning vacant land management organizations with robust youth engagement capabilities engage youth in their greening work. Based on in-depth interviews with staff from vacant land management organizations, we explored three research questions: (1) what are their identified best practices for youth engagement?; (2) what are the major challenges that impede their youth engagement work?; (3) what solutions are these organizations employing to address these challenges? Findings from this study emphasize the important themes of engaging youth in vacant lot greening in areas of planning, leadership, and decision-making. Youth engagement in vacant lot greening may be a key mechanism for preventing violence through cultivating youth empowerment and development.

Community engagement, greening, and violent crime: A test of the greening hypothesis and Busy Streets.

Researchers have documented that vacant lot greening can reduce community-level crime and violence. Busy Streets Theory (BST) suggests that residents who are involved in the greening process can help to improve physical environments and build social connections that deter crime and violence. Yet few researchers have explored how community engagement in the greening process may affect crime and violence outcomes. We applied BST to test the effects of community-engaged vacant lot greening compared to vacant lots that received either professional mowing or no treatment, on the density of violent crime around study lots. Using mixed effects regression models, we analyzed trends in violent crime density over the summer months from 2016 to 2018 at 2102 street segments in Youngstown, OH. These street segments fell within 150 meters of an intervention parcel that was classified as one of three conditions: community-engaged maintenance, professional mowing, or no treatment (control). We found that street segments in areas receiving community-engaged maintenance or professional mowing experienced greater declines in violent crime density than street segments in areas receiving no treatment, and more decline occurred in the community-engaged condition compared to the professional mow condition. Our findings support BST and suggest that community-engaged greening of vacant lots in postindustrial cities with a concentrated vacancy can reduce crime and violence.

Neighborhood segregation, tree cover and firearm violence in 6 U.S. cities, 2015-2020.

Neighborhood segregation by race and income is a structural determinant of firearm violence. Addressing green space deficits in segregated neighborhoods is a promising prevention strategy. This study assessed the potential for reducing firearm violence disparities by increasing access to tree cover. Units of analysis were census tracts in six U.S. cities (Baltimore, MD; Philadelphia, PA; Richmond, VA; Syracuse, NY; Washington, DC; Wilmington, DE). We measured segregation using the index of concentration at the extremes (ICE) for race-income. We calculated proportion tree cover based on 2013-2014 imagery. Outcomes were 2015-2020 fatal and non-fatal shootings from the Gun Violence Archive. We modeled firearm violence as a function of ICE, tree cover, and covariates representing the social and built environment. Next, we simulated possible effects of "tree equity" programs, i.e., raising tract-level tree cover to a specified baseline level. In our fully-adjusted model, higher privilege on the ICE measure (1 standard deviation, SD) was associated with a 42% reduction in shootings (incidence rate ratio (IRR) = 0.58, 95% CI [0.54 0.62], p < 0.001). A 1-SD increase in tree cover was associated with a 9% reduction (IRR = 0.91, 95% CI [0.86, 0.97], p < 0.01). Simulated achievement of 40% baseline tree cover was associated with reductions in firearm violence, with the largest reductions in highly-deprived neighborhoods. Advancing tree equity would not disrupt the fundamental causes of racial disparities in firearm violence exposure, but may have the potential to help mitigate those disparities.

Neighborhood Blighted Property Removal and 311 Calls for Non-Emergency Services: A Test of a Marker of Social Control.

Many studies have demonstrated that collective efficacy is associated with positive health outcomes, lower crime, and violence in urban communities, and residents' emotional connection to their community. Remediation of blighted properties has been theoretically linked to increases in collective efficacy. The purpose of this study was to examine the impact of blighted property remediation on city non-emergency 311 calls for public incivilities and deterioration, as potential markers of collective efficacy. We used a quasi-experimental design to test whether 311 calls for service changed around remediated vacant lots in New Orleans, Louisiana, United States, many of which were left vacant after Hurricane Katrina in 2005. In six city neighborhoods eligible for blighted property remediation as part of a city program, 203 treated vacant lots were matched 1:3 without replacement to control lots that were eligible for but did not receive treatment. This yielded a total of 812 vacant lots partitioned within 48 months, or 38,976 lot-months. Controls were in the same New Orleans neighborhoods as their matched treatment lots but were at least 250 feet away to minimize contamination. Overall difference-in-differences models detected postintervention declines in calls related to dumping and garbage, and slight but mostly non-significant changes in calls between intervention and control lots in all but calls for dumping and vehicles. Blighted property remediation may have an impact on dumping and garbage, which is important. Despite being geographically specific, low-cost and longitudinal, the nature of 311 calls and structural and historic factors at play in both the concentration of vacant properties in communities and residents' willingness to call must be considered. Further analyses of changes in 311 data and additional qualitative inquiry are warranted to more fully determine the utility of these data.

Stress and Distress during the COVID-19 Pandemic: The Role of Neighborhood Context.

Neighborhoods play a central role in health and mental health, particularly during disasters and crises such as the COVID-19 pandemic. We examined changes in psychological distress following the pandemic, and the potential role of neighborhood conditions among 244 residents of New Orleans, Louisiana. Using modified linear regression models, we assessed associations between neighborhood characteristics and change in psychological distress from before to during the pandemic, testing effect modification by sex and social support. While higher density of offsite alcohol outlets (ß = 0.89; 95% CI: 0.52, 1.23), assault rate (ß = 0.14; 95% CI: 0.03, 0.24), and walkable streets (ß = 0.05; 95% CI: 0.02, 0.07) in neighborhoods were associated with an increase in distress, access to neighborhood parks (ß = -0.03; 95% CI: -0.05, -0.01), collective efficacy (ß = -0.23; 95% CI: -0.35, -0.09), and homicide rate (ß = -1.2; 95% CI: -1.8, -0.6) were associated with reduced distress related to the pandemic. These relationships were modified by sex and social support. Findings revealed the important but complicated relationship between psychological distress and neighborhood characteristics. While a deeper understanding of the neighborhoods' role in distress is needed, interventions that target neighborhood environments to ameliorate or prevent the residents' distress may be important not only during crisis situations.

Socioeconomic Disparities in Hypertension by Levels of Green Space Availability: A Cross-Sectional Study in Philadelphia, PA.

Green spaces have been proposed as equigenic factors, potentially mitigating health disparities. We used data from the 3887 participants residing in Philadelphia who participated in the Public Health Management Corporation's Southeastern Pennsylvania Household Health Survey in 2014-2015 to assess whether socioeconomic disparities in hypertension are modified by availability of neighborhood-level green spaces. Socioeconomic status (SES) was measured using individual-level education and neighborhood-level median household income. Green space availability was measured using surrounding percent tree canopy cover, mean normalized difference vegetation index (NDVI), and proximity to nearest park. Using logistic regression models adjusted for age, sex, and race/ethnicity, we found that adults with higher educational attainment had significantly lower levels of hypertension (OR = 0.63, 0.57, and 0.36 for high school, some college, and college graduates, respectively, as compared to those with less than high school education), and this pattern was similar for median household income (higher prevalence in lower income areas). We found no significant interaction between education and percent tree canopy cover (p = 0.83), meaning that educational disparities in hypertension were similar across all levels of green space availability. These results held when using mean NDVI or distance to nearest park as availability measures, or when considering neighborhood-level median household income as the socioeconomic measure, although the specific patterns and significance of interactions varied by exposure and modifier. While socioeconomic disparities in hypertension are strong for adults residing in Philadelphia, green spaces did not seem to modify them.

Spatial predictors of heavy metal concentrations in epiphytic moss samples in Seattle, WA.

The use of bio-indicators is an emerging, cost-effective alternative approach to identifying air pollution and assessing the need for additional air monitoring. This community science project explores the use of moss samples as bio-indicators of the distribution of metal air particulates in two residential neighborhoods of the industrial Duwamish Valley located in Seattle, WA (USA). We applied geographically weighted regression to data from 61 youth-collected samples to assess the location-specific area-level spatial predictors of the concentrations of 25 elements with focus on five heavy metals of concern due to health and environmental considerations. Spatial predictors included traffic volume, industrial land uses, major roadways, the airport, dirt roads, the Duwamish River, impervious surfaces, tree canopy cover, and sociodemographics. Traffic volume surrounding sample locations was the most consistent positive predictor of increasing heavy metal concentration. Greater distance from the heavy-industry corridor surrounding the Duwamish River predicted lower concentrations of all metals, with statistically significant associations for chromium and lead in some areas. As the distance from dirt roads increased, the concentration of arsenic and chromium decreased significantly. Percent tree canopy within 200 m of sample locations was a significant protective factor for cadmium concentrations. In addition, percent people of color was significantly positively associated with increasing lead, chromium and nickel concentrations. Our findings underscore the potential influence of heavy industry and mobile sources on heavy metal concentrations, the buffering potential of trees in local environments, and persistent opportunity to improve environmental justice.

Community Greening, Fear of Crime, and Mental Health Outcomes.

Unmaintained vacant land in urban areas is associated with a number of negative outcomes for residents of urban areas, including mental and physical health, safety, and quality of life. Community programs which promote land parcel maintenance in urban neighborhoods have been found to reverse some of the effects that unmaintained land has on nearby residents. We explored how land parcel maintenance is associated with mental health outcomes using data collected in Flint, MI in 2017-2018. Trained observers assessed the maintenance of approximately 7200 land parcels and surveyed 691 residents (57% Female, 53% Black, M age = 51). We aggregated resident and parcel rating data to 463 street segments and compared three structural equation models (SEM) to estimate the mediating effects of fear of crime on the association of parcel qualities on mental distress for residents. We found that fear of crime mediated the association between parcel maintenance values and mental distress indicating that poor maintenance predicted more fear of crime which was associated with mental distress. Our findings add to our understanding about the mechanism by which vacant lot improvements may operate to enhance psychological well-being of residents who live on streets with vacant and unkept lots.

Socio-demographic and health vulnerability in prescribed-burn exposed versus unexposed counties near the National Forest System.

Prescribed fire is an increasingly important tool in restoring ecological conditions and reducing uncontrolled wildfire. Prescribed burn techniques could reduce public health impacts associated with wildfire smoke exposure. However, there have been few assessments of the health impacts of prescribed burning, and potential vulnerabilities among populations exposed to smoke from prescribed fires. Our study area focused on counties in and near U.S. National Forests - a set of lands distributed across the U.S. In county-level analyses, we compared the sociodemographic and health characteristics of areas that were exposed with those that were not exposed to prescribe burns during the years 2010-2019 on a national level and within three regions. In addition, using spatial error regression models, we looked for associations between prescribed fire exposure and health behaviors and outcomes while controlling for spatial autocorrelation. On a national level, we found disproportionate prescribed fire exposure in rural counties with higher percentage mobile home and vacant housing units, and higher percentage African-American and white populations. Regionally, we found evidence of disproportionate exposure to prescribed burns among counties with lower percentage white population, higher percentage Hispanic population and mobile homes in the southern region, and to high poverty counties with high vacancy in the western region. These findings could indicate that vulnerable populations face potential health risks from prescribed burning smoke exposure, but also that they are not missing out on the benefits of prescribed burning, which could involve considerably lower smoke exposure compared to uncontrolled wildfire. In addition, in regression analyses, we found no evidence of disproportionate health burden in exposed compared to unexposed counties. Awareness of these patterns could influence both large-scale or institutional polices about prescribed burning practice, and could be used to build decision-making factors into modeling tools and smoke management plans, as well as community-engagement around wildfire risk reduction.

Gender Differences in Impacts of Place-Based Neighborhood Greening Interventions on Fear of Violence Based on a Cluster-Randomized Controlled Trial.

Maintained green space in underserved urban neighborhoods may be an important environmental pathway to improving community health and safety, though effects may vary across population subgroups and by time of day. We examined survey responses from 442 participants (178 men and 264 women), living near vacant lots in a cluster-randomized controlled trial of a cleaning and greening intervention, on perceived safety during the day and at night. At the intervention sites after the intervention, only men reported feeling less unsafe during the day. Women reported more fear, and men reported less fear, after the intervention, although these results and tests for effect modification were not statistically significant. The clean-and-green intervention may have allayed fears for men during the day and supported their ease of movement throughout their neighborhoods. However, at night, it may have had the opposite effect on women. Though our study was under-powered, not designed to test associations stratified by gender, directions and magnitudes of associations differed substantially, indicating a need for further investigations into potential gender differences in the benefits of green space, to inform and better tailor interventions to improve perceived safety for all.

The association between blighted property remediation and domestic crime by alcohol availability.

There is increasing evidence that place-based interventions reduce crime and interpersonal violence in urban settings. However, evidence concerning the impacts of these neighborhood interventions on domestic crime (crime between intimate partners, family, or household members) is inconclusive. We used data from a New Orleans, Louisiana, place-based blighted property remediation intervention to test the hypothesis that the intervention was associated with changes in domestic crime. Because there is evidence that alcohol availability is related to domestic crime, we also assessed whether this association was moderated by alcohol outlet density. We assessed overall associations using a difference-in-difference approach and assessed moderation using a triple-difference approach. The analytic sample consisted of 204 remediated lots and 612 non-remediated matched control lots over 84 months (2011-2017), for a total of 68,544 lot-months. In difference-in-differences analyses, the place-based intervention was associated with additional domestic crime incidence (ß = 0.311, 95% CI: 0.016, 0.605; p = 0.039). In triple-difference analyses, on-premise bar density modified this association (ß = -0.119, 95%CI: -0.147, -0.092; p < 0.001): in areas with higher bar density, increases in domestic crime were lower near remediated lots compared with control lots. Place-based interventions to reduce blighted properties may have contributed to fewer domestic crime incidents in areas with more bars.

Assessing the impact of a local community subsidised rideshare programme on road traffic injuries: an evaluation of the Evesham Saving Lives programme.

BACKGROUND: Alcohol-related vehicle crashes pose a significant challenge to public health in suburban communities. The Evesham Saving Lives programme operated between late 2015 and 2019 in two townships (Evesham and Voorhees) in New Jersey. The programme subsidised rideshare (eg, Uber) trips from bars and restaurants between the hours of 21:00 and 02:00 to prevent alcohol-related traffic injuries. METHODS: This study used data from the New Jersey Department of Transportation to examine changes to rates of injury crashes between 2010 and 2018. We used an ecological difference-in-difference design with Bayesian conditional autoregressive Poisson models to compare rates of injury crashes between participating municipalities (n=2) and non-participating municipalities (n=75). Sensitivity analyses included comparison with a weighted synthetic control series. RESULTS: The Evesham Saving Lives programme was associated with 18% fewer injury crashes overall (IRR=0.82, 95% credible interval (CrI): 0.76, 0.88). Reductions in crashes were estimated to be greatest at night (IRR=0.62, 95% CrI: 0.48, 0.79), with moderate reductions in the afternoon (IRR=0.80, 95% CrI: 0.72, 0.88). We estimate that around three lives were saved (95% CrI: 2, 5) and around 371 injuries were prevented (95% CrI: 204, 625), potentially making considerable savings in terms of medical and economic expenses. CONCLUSIONS: These findings support the claim that improving the convenience and reducing the costs of alternative night-time transportation can prevent road traffic injuries. Future studies should aim to replicate these analyses in programmes that have been implemented in other suburban communities across the US.