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.

Comparing mapped park and greenspace boundaries in Philadelphia: implications for exposure assessment in health studies.

An important consideration in studies of the relationship between greenspace exposure and health is the use of mapped data to assign geographic exposures to participants. Previous studies have used validated data from municipal park departments to describe the boundaries of public greenspaces. However, this approach assumes that these data accurately describe park boundaries, that formal parks fully capture the park and greenspace exposure of residents, and (for studies that use personal GPS traces to assign participant exposures) that time spent within these boundaries represents time spent in greenspace. These assumptions are tested using a comparison and ground-truthing of four sources of mapped park and greenspace data in Philadelphia, Pennsylvania: PAD-US-AR, Philadelphia Parks and Recreation, the Delaware Valley Regional Planning Commission, and Open Street Maps. We find several important differences and tradeoffs in these data: the incorporation of highways and building lots within park boundaries, the inclusion or exclusion of formal park spaces (federal, state, and nonprofit), the exclusion of informal parks and greenspaces, and inconsistent boundaries for a linear park. Health researchers may wish to consider these issues when conducting studies using boundary data to assign park exposure.

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.

Commentary: A road map for future data-driven urban planning and environmental health research.

Recent advances in data science and urban environmental health research utilise large-scale databases (100s-1000s of cities) to explore the complex interplay of urban characteristics such as city form and size, climate, mobility, exposure, and environmental health impacts. Cities are still hotspots of air pollution and noise, suffer urban heat island effects and lack of green space, which leads to disease and mortality burdens preventable with better knowledge. Better understanding through harmonising and analysing data in large numbers of cities is essential to identifying the most effective means of disease prevention and understanding context dependencies important for policy.

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.

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.

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.

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.

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.

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.

Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear.

Vacant and blighted urban land is a widespread and potentially risky environmental condition encountered by millions of people on a daily basis. About 15% of the land in US cities is deemed vacant or abandoned, an area roughly the size of Switzerland. In a citywide cluster randomized controlled trial, we investigated the effects of standardized, reproducible interventions that restore vacant land on the commission of violence, crime, and the perceptions of fear and safety. Quantitative and ethnographic analyses were included in a mixed-methods approach to more fully test and explicate our findings. A total of 541 randomly sampled vacant lots were randomly assigned into treatment and control study arms; outcomes from police and 445 randomly sampled participants were analyzed over a 38-month study period. Participants living near treated vacant lots reported significantly reduced perceptions of crime (-36.8%, P < 0.05), vandalism (-39.3%, P < 0.05), and safety concerns when going outside their homes (-57.8%, P < 0.05), as well as significantly increased use of outside spaces for relaxing and socializing (75.7%, P < 0.01). Significant reductions in crime overall (-13.3%, P < 0.01), gun violence (-29.1%, P < 0.001), burglary (-21.9%, P < 0.001), and nuisances (-30.3%, P < 0.05) were also found after the treatment of vacant lots in neighborhoods below the poverty line. Blighted and vacant urban land affects people's perceptions of safety, and their actual, physical safety. Restoration of this land can be an effective and scalable infrastructure intervention for gun violence, crime, and fear in urban neighborhoods.

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.

Nature Rx: Reemergence of Pediatric Nature-Based Therapeutic Programs From the Late 19th and Early 20th Centuries.

Across the United States, physicians are prescribing patients nature. These "Nature Rx" programs promote outdoor activity as a measure to combat health epidemics stemming from sedentary lifestyles. Despite the apparent novelty of nature prescription programs, they are not new. Rather, they are a reemergence of nature-based therapeutics that characterized children's health programs in the late 19th and early 20th centuries. These historic programs were popular among working-class urban families, physicians, and public health officials. By contrast, adherence is a challenge for contemporary programs, especially in socially disadvantaged areas. Although there are differences in nature prescription programs and social context, historical antecedents provide important lessons about the need to provide accessible resources and build on existing social networks. They also show that nature-and its related health benefits-does not easily yield itself to precise scientific measurements or outcomes. Recognizing these constraints may be critical to nature prescription programs' continued success and support from the medical profession.

Neighborhood Interventions to Reduce Violence.

Violence is a widespread problem that affects the physical, mental, and social health of individuals and communities. Violence comes with an immense economic cost to its victims and society at large. Although violence interventions have traditionally targeted individuals, changes to the built environment in places where violence occurs show promise as practical, sustainable, and high-impact preventive measures. This review examines studies that use quasi-experimental or experimental designs to compare violence outcomes for treatment and control groups before and after a change is implemented in the built environment. The most consistent evidence exists in the realm of housing and blight remediation of buildings and land. Some evidence suggests that reducing alcohol availability, improving street connectivity, and providing green housing environments can reduce violent crimes. Finally, studies suggest that neither transit changes nor school openings affect community violence.

The Association Between Urban Tree Cover and Gun Assault: A Case-Control and Case-Crossover Study.

Green space and vegetation may play a protective role against urban violence. We investigated whether being near urban tree cover during outdoor activities was related to being assaulted with a gun. We conducted geographic information systems-assisted interviews with boys and men aged 10-24 years in Philadelphia, Pennsylvania, including 135 patients who had been shot with a firearm and 274 community controls, during 2008-2011. Each subject reported a step-by-step mapped account of where and with whom they traveled over a full day from waking until being assaulted or going to bed. Geocoded path points were overlaid on mapped layers representing tree locations and place-specific characteristics. Conditional logistic regressions were used to compare case subjects versus controls (case-control) and case subjects at the time of injury versus times earlier that day (case-crossover). When comparing cases at the time of assault to controls matched at the same time of day, being under tree cover was inversely associated with gunshot assault (odds ratio (OR) = 0.70, 95% confidence interval (CI): 0.55, 0.88), especially in low-income areas (OR = 0.69, 95% CI: 0.54, 0.87). Case-crossover models confirmed this inverse association overall (OR = 0.55, 95% CI: 0.34, 0.89) and in low-income areas (OR = 0.54, 95% CI: 0.33, 0.88). Urban greening and tree cover may hold promise as proactive strategies to decrease urban violence.

Urban Blight Remediation as a Cost-Beneficial Solution to Firearm Violence.

OBJECTIVES: To determine if blight remediation of abandoned buildings and vacant lots can be a cost-beneficial solution to firearm violence in US cities. METHODS: We performed quasi-experimental analyses of the impacts and economic returns on investment of urban blight remediation programs involving 5112 abandoned buildings and vacant lots on the occurrence of firearm and nonfirearm violence in Philadelphia, Pennsylvania, from 1999 to 2013. We adjusted before-after percent changes and returns on investment in treated versus control groups for sociodemographic factors. RESULTS: Abandoned building remediation significantly reduced firearm violence -39% (95% confidence interval [CI] = -28%, -50%; P < .05) as did vacant lot remediation (-4.6%; 95% CI = -4.2%, -5.0%; P < .001). Neither program significantly affected nonfirearm violence. Respectively, taxpayer and societal returns on investment for the prevention of firearm violence were $5 and $79 for every dollar spent on abandoned building remediation and $26 and $333 for every dollar spent on vacant lot remediation. CONCLUSIONS: Abandoned buildings and vacant lots are blighted structures seen daily by urban residents that may create physical opportunities for violence by sheltering illegal activity and illegal firearms. Urban blight remediation programs can be cost-beneficial strategies that significantly and sustainably reduce firearm violence.

Elemental Concentrations in Urban Green Stormwater Infrastructure Soils.

Green stormwater infrastructure (GSI) is designed to capture stormwater for infiltration, detention, evapotranspiration, or reuse. Soils play a key role in stormwater interception at these facilities. It is important to assess whether contamination is occurring in GSI soils because urban stormwater drainage areas often accumulate elements of concern. Soil contamination could affect hydrologic and ecosystem functions. Maintenance workers and the public may also be exposed to GSI soils. We investigated soil elemental concentrations, categorized as macro- and micronutrients, heavy metals, and other elements, at 59 GSI sites in the city of Philadelphia. Non-GSI soil samples 3 to 5 m upland of GSI sites were used for comparison. We evaluated differences in elemental composition in GSI and non-GSI soils; the comparisons were corrected for the age of GSI facility, underlying soil type, street drainage, and surrounding land use. Concentrations of Ca and I were greater than background levels at GSI sites. Although GSI facilities appear to accumulate Ca and I, these elements do not pose a significant human health risk. Elements of concern to human health, including Cd, Hg, and Pb, were either no different or were lower in GSI soils compared with non-GSI soils. However, mean values found across GSI sites were up to four times greater than soil cleanup objectives for residential use.

The impact of green stormwater infrastructure installation on surrounding health and safety.

OBJECTIVES: We investigated the health and safety effects of urban green stormwater infrastructure (GSI) installments. METHODS: We conducted a difference-in-differences analysis of the effects of GSI installments on health (e.g., blood pressure, cholesterol and stress levels) and safety (e.g., felonies, nuisance and property crimes, narcotics crimes) outcomes from 2000 to 2012 in Philadelphia, Pennsylvania. We used mixed-effects regression models to compare differences in pre- and posttreatment measures of outcomes for treatment sites (n=52) and randomly chosen, matched control sites (n=186) within multiple geographic extents surrounding GSI sites. RESULTS: Regression-adjusted models showed consistent and statistically significant reductions in narcotics possession (18%-27% less) within 16th-mile, quarter-mile, half-mile (P<.001), and eighth-mile (P<.01) distances from treatment sites and at the census tract level (P<.01). Narcotics manufacture and burglaries were also significantly reduced at multiple scales. Nonsignificant reductions in homicides, assaults, thefts, public drunkenness, and narcotics sales were associated with GSI installation in at least 1 geographic extent. CONCLUSIONS: Health and safety considerations should be included in future assessments of GSI programs. Subsequent studies should assess mechanisms of this association.