Feature extraction and machine learning techniques for identifying historic urban environmental hazards: New methods to locate lost fossil fuel infrastructure in US cities.

U.S. cities contain unknown numbers of undocumented "manufactured gas" sites, legacies of an industry that dominated energy production during the late-19th and early-20th centuries. While many of these unidentified sites likely contain significant levels of highly toxic and biologically persistent contamination, locating them remains a significant challenge. We propose a new method to identify manufactured gas production, storage, and distribution infrastructure in bulk by applying feature extraction and machine learning techniques to digitized historic Sanborn fire insurance maps. Our approach, which relies on a two-part neural network to classify candidate map regions, increases the rate of site identification 20-fold compared to unaided visual coding.

Association Between Structural Housing Repairs for Low-Income Homeowners and Neighborhood Crime.

Importance: The root causes of violent crime in Black urban neighborhoods are structural, including residential racial segregation and concentrated poverty. Previous work suggests that simple and scalable place-based environmental interventions can overcome the legacies of neighborhood disinvestment and have implications for health broadly and crime specifically. Objective: To assess whether structural repairs to the homes of low-income owners are associated with a reduction in nearby crime. Design, Setting, and Participants: This cross-sectional study using difference-in-differences analysis included data from the City of Philadelphia Basic Systems Repair Program (BSRP) from January 1, 2006, through April 30, 2013. The unit of analysis was block faces (single street segments between 2 consecutive intersecting streets) with or without homes that received the BSRP intervention. The blocks of homes that received BSRP services were compared with the blocks of eligible homes that were still on the waiting list. Data were analyzed from December 1, 2019, to February 28, 2021. Exposures: The BSRP intervention includes a grant of up to $20 000 provided to low-income owners for structural repairs to electrical, plumbing, heating, and roofing damage. Eligible homeowners must meet income guidelines, which are set by the US Department of Housing and Urban Development and vary yearly. Main Outcomes and Measures: The main outcome was police-reported crime across 7 major categories of violent and nonviolent crimes (homicide, assault, burglary, theft, robbery, disorderly conduct, and public drunkenness). Results: A total of 13 632 houses on 6732 block faces received the BSRP intervention. Owners of these homes had a mean (range) age of 56.5 (18-98) years, were predominantly Black (10 952 [78.6%]) or Latino (1658 [11.9%]) individuals, and had a mean monthly income of $993. These census tracts compared with those without BSRP intervention had a substantially larger Black population (49.5% vs 12.2%; |D| = 0.406) and higher unemployment rate (17.3% vs 9.3%; |D| = 0.357). The main regression analysis demonstrated that the addition to a block face of a property that received a BSRP intervention was associated with a 21.9% decrease in the expected count of total crime (incidence rate ratio [IRR], 0.78; 95% CI, 0.76-0.80; P < .001), 19.0% decrease in assault (IRR, 0.81; 95% CI, 0.79-0.84; P < .001), 22.6% decrease in robbery (IRR, 0.77; 95% CI, 0.75-0.80; P < .001), and 21.9% decrease in homicide (IRR, 0.78; 95% CI, 0.71-0.86; P < .001). When restricting the analysis to blocks with properties that had ever received a BSRP intervention, a total crime reduction of 25.4% was observed for each additional property (IRR, 0.75; 95% CI, 0.73-0.77; P < .001). A significant dose-dependent decrease in total crime was found such that the magnitude of association increased with higher numbers of homes participating in the BSRP on a block. Conclusions and Relevance: This study found that the BSRP intervention was associated with a modest but significant reduction in crime. These findings suggest that intentional and targeted financial investment in structural, scalable, and sustainable place-based interventions in neighborhoods that are still experiencing the lasting consequences of structural racism and segregation is a vital step toward achieving health equity.

Ambient urban N deposition drives increased biomass and total plant N in two native prairie grass species in the U.S. Southern Great Plains.

Remnants of native tallgrass prairie experience elevated atmospheric nitrogen (N) deposition in urban areas, with potential effects on species traits that are important for N cycling and species composition. We quantified bulk (primarily wet) inorganic N (NH4+-N + NO3--N) deposition at six sites along an urban development gradient (6-64% urban) in the Dallas-Fort Worth metropolitan area from April 2014 to October 2015. In addition, we conducted a phytometer experiment with two common native prairie bunchgrass species--one well studied (Schizachyrium scoparium) and one little studied (Nasella leucotricha)--to investigate ambient N deposition effects on plant biomass and tissue quality. Bulk inorganic N deposition ranged from 6.1-9.9 kg ha-1 yr-1, peaked in spring, and did not vary consistently with proportion of urban land within 10 km of the sites. Total (wet + dry) inorganic N deposition estimated using bulk deposition measured in this study and modeled dry deposition was 12.9-18.2 kg ha-1 yr-1. Although the two plant species studied differ in photosynthetic pathway, biomass, and tissue N, they exhibited a maximum 2-3-fold and 2-4-fold increase in total biomass and total plant N, respectively, with 1.6-fold higher bulk N deposition. In addition, our findings indicate that while native prairie grasses may exhibit a positive biomass response to increased N deposition up to ~18 kg ha-1 yr-1, total inorganic N deposition is well above the estimated critical load for herbaceous plant species richness in the tallgrass prairie of the Great Plains ecoregion and thus may negatively affect these plant communities.

The spatial coupling effect between urban street network's centrality and collection & delivery points: A spatial design network analysis-based study.

The sustainable development of collection and delivery points and urban street network is an important consideration of logistic planners. Urban street networks have a significant impact on collection and delivery points' location, but the spatial relationship between the centrality of urban street network and collection and delivery points has not been studied using spatial design network analysis. In a multiple centrality assessment model, we used point of interest and street network data to evaluate the location of two types of collection and delivery points and the centrality of streets in Nanjing city, based on four indicators: closeness, betweenness, severance, and efficiency. Then, kernel density estimation and spatial autocorrelation are used to study spatial patterns of distribution and centrality coupling effects of urban street network and collection and delivery points. The results show that the centrality of Nanjing streets has a big influence on the location of the collection and delivery points, and the directions of different types of centrality also vary. The location of the Cainiao Stations are largely related to closeness, followed by betweenness, severance, and efficiency. China Post Stations and street centrality have a weak correlation between efficiency and severance, but no correlation between closeness and betweenness. Our results can help logistics enterprises and urban planners to develop collection and delivery points' network based on the urban street network.

The persistence of ancient settlements and urban sustainability.

We propose a dedicated research effort on the determinants of settlement persistence in the ancient world, with the potential to significantly advance the scientific understanding of urban sustainability today. Settlements (cities, towns, villages) are locations with two key attributes: They frame human interactions and activities in space, and they are where people dwell or live. Sustainability, in this case, focuses on the capacity of structures and functions of a settlement system (geography, demography, institutions) to provide for continuity of safe habitation. The 7,000-y-old experience of urbanism, as revealed by archaeology and history, includes many instances of settlements and settlement systems enduring, adapting to, or generating environmental, institutional, and technological changes. The field of urban sustainability lacks a firm scientific foundation for understanding the long durée, relying instead on narratives of collapse informed by limited case studies. We argue for the development of a new interdisciplinary research effort to establish scientific understanding of settlement and settlement system persistence. Such an effort would build upon the many fields that study human settlements to develop new theories and databases from the extensive documentation of ancient and premodern urban systems. A scientific foundation will generate novel insights to advance the field of urban sustainability.

Impacts of Gentrification on Health in the US: a Systematic Review of the Literature.

Gentrification in the largest 50 US cities has more than doubled since the 1990s. The process of gentrification can bring about improved neighborhood conditions, reduced rates of crime, and property value increases. At the same time, it can equally foster negative conditions associated with poorer health outcomes, such as disrupted social networks from residential displacement and increases in stress. While neighborhood environment is consistently implicated in health outcomes research, gentrification is rarely conceptualized as a public health issue. Though research on gentrification is growing, empirical studies evaluating the health impacts of gentrification in the US are poorly understood. Here we systematically review US population-based empirical studies examining relationships between gentrification and health. Electronic databases (PubMed, Embase, CINAHL, PsycINFO, Scopus, Web of Science, and Academic Search Complete) were searched using a combination of terms to identify peer-reviewed studies published on or before July 9, 2018, reporting associations between gentrification and health. Study title and abstract screenings were followed by full-text review of all studies meeting the following inclusion criteria of: ≥ 1 quantitative measure of association for a health outcome, within the context of gentrification; peer-reviewed research; located in the US; and English language. Of 8937 studies identified, 6152 underwent title and abstract screening, and 50 studies underwent full-text screening, yielding six studies for review. Gentrification exposure measures and health outcomes examined varied widely. Most studies reported little to no overall association between gentrification and health outcomes; however, gentrification was repeatedly associated with undesirable health effects among Black and economically vulnerable residents. Despite seemingly overall null associations between gentrification and health, evidence suggests that gentrification may negatively impact the health of certain populations, particularly Black and low-income individuals. Complexities inherent in operationalizing gentrification point toward the need for validated measures. Additionally, understanding how gentrification-health associations differ across health endpoints, race/ethnicities, socioeconomic status, and life course can provide insight into whether this process contributes to urban inequality and health disparities. As gentrification occurs across the US, it is important to understand how this process impacts health. While aging cities reinvest in the revitalization of communities, empirical research examining relationships between gentrification and health can help inform policy decisions.

On the relation between transversal and longitudinal scaling in cities.

Does the scaling relationship between population sizes of cities with urban metrics like economic output and infrastructure (transversal scaling) mirror the evolution of individual cities in time (longitudinal scaling)? The answer to this question has important policy implications, but the lack of suitable data has so far hindered rigorous empirical tests. In this paper, we advance the debate by looking at the evolution of two urban variables, GDP and water network length, for over 5500 cities in Brazil. We find that longitudinal scaling exponents are city-specific. However, they are distributed around an average value that approaches the transversal scaling exponent provided that the data is decomposed to eliminate external factors, and only for cities with a sufficiently high growth rate. We also introduce a mathematical framework that connects the microscopic level to global behaviour, finding good agreement between theoretical predictions and empirical evidence in all analyzed cases. Our results add complexity to the idea that the longitudinal dynamics is a micro-scaling version of the transversal dynamics of the entire urban system. The longitudinal analysis can reveal differences in scaling behavior related to population size and nature of urban variables. Our approach also makes room for the role of external factors such as public policies and development, and opens up new possibilities in the research of the effects of scaling and contextual factors.

Impact of gentrification on adult mental health.

OBJECTIVE: To estimate the net effect of living in a gentrified neighborhood on probability of having serious psychological distress. DATA SOURCES: We pooled 5 years of secondary data from the California Health Interview Survey (2011-2015) and focused on southern California residents. STUDY DESIGN: We compared adults (n = 43 815) living in low-income and gentrified, low-income and not gentrified, middle- to high-income and upscaled, and middle- to high-income and not upscaled neighborhoods. We performed a probit regression to test whether living in a gentrified neighborhood increased residents' probabilities of having serious psychological distress in the past year and stratified analyses by neighborhood tenure, homeownership status, and low-income status. Instrumental variables estimation and propensity scores were applied to reduce bias arising from residential selection and simultaneity. An endogenous treatment effects model was also applied in sensitivity analyses. DATA COLLECTION/EXTRACTION METHODS: Adults who completed the survey on their own and lived in urban neighborhoods with 500 or more residents were selected for analyses. Survey respondents who scored 13 and above on the Kessler 6 were categorized as having serious psychological distress in the past year. We used eight neighborhood change measures to classify respondents' neighborhoods. PRINCIPAL FINDINGS: Living in a gentrified and upscaled neighborhood was associated with increased likelihood of serious psychological distress relative to living in a low-income and not gentrified neighborhood. The average treatment effect was 0.0141 (standard error = 0.007), which indicates that the prevalence of serious psychological distress would have been 1.4 percentage points less if none of the respondents lived in gentrified neighborhoods. Gentrification appears to have a negative impact on the mental health of renters, low-income residents, and long-term residents. This effect was not observed among homeowners, higher-income residents, and recent residents. CONCLUSIONS: Gentrification levies mental health costs on financially vulnerable community members and can worsen mental health inequities.

Gentrification, Neighborhood Change, and Population Health: a Systematic Review.

Despite a proliferation of research on neighborhood effects on health, how neighborhood economic development, in the form of gentrification, affects health and well-being in the USA is poorly understood, and no systematic assessment of the potential health impacts has been conducted. Further, we know little about whether health impacts differ for residents of neighborhoods undergoing gentrification versus urban development, or other forms of neighborhood socioeconomic ascent. We followed current guidelines for systematic reviews and present data on the study characteristics of the 22 empirical articles that met our inclusion criteria and were published on associations between gentrification, and similar but differently termed processes (e.g., urban regeneration, urban development, neighborhood upgrading), and health published between 2000 and 2018. Our results show that impacts on health vary by outcome assessed, exposure measurement, the larger context-specific determinants of neighborhood change, and analysis decisions including which reference and treatment groups to examine. Studies of the health impacts of gentrification, urban development, and urban regeneration describe similar processes, and synthesis and comparison of their results helps bridge differing theoretical approaches to this emerging research. Our article helps to inform the debate on the impacts of gentrification and urban development for health and suggests that these neighborhood change processes likely have both detrimental and beneficial effects on health. Given the influence of place on health and the trend of increasing gentrification and urban development in many American cities, we discuss how future research can approach understanding and researching the impacts of these processes for population health.

Spatial characteristics and risk factor identification for land use spatial conflicts in a rapid urbanization region in China.

Land use conflict is a complex problem driven by a myriad of risk factors as a result of rapid socioeconomic development and urbanization. Analyzing the spatial characteristics of land use conflict and identifying its risk factors using statistical models will help us to better understand the causes and effects of the land use conflicts for sustainable management of the limited land resources under the pressure of rapid urbanization. In this study, regression models including multiple linear regression (MLR), spatial autoregressive (SAR), and geographically weighted regression (GWR) models were employed to identify risk factors for the land use spatial conflicts in the Urban Agglomeration around Hangzhou Bay (UAHB) of China in the past 25 years. Our results showed that the overall extent and the higher-level land use spatial conflicts were actually on the decline, and their spatial autocorrelation has been weakening in the UAHB. The key risk factors that mainly caused the land use spatial conflicts in the UHAB appeared to be different at the global and local scales. This knowledge should help urban managers and policymakers to be better informed when developing pertinent land use policies at the regional and local levels. This study also underlined the importance of considering spatial autocorrelation and scale effects when identifying the risk factors for land use spatial conflicts. The lessons learned from this particular context can be extended to other areas under rapid urbanization to assess and better manage their land resources for sustainable use. Graphical abstract.

Stream flow composition and sediment yield comparison between partially urbanized and undisturbed coastal watersheds-case study: St. John, US Virgin Islands.

In steep dry-tropical islands, rural and urban development can lead to accelerated soil erosion and the delivery of land-based materials into marine ecosystems. The objective of this paper was to compare stream water composition, clay minerology, and sediment yield between a partially urbanized (Coral Bay) and an undisturbed (Lameshur) coastal watersheds in St. John, US Virgin Islands (USVI). The saturation index of streamflow water samples was calculated using "The Geochemist's Workbench" software and most likely precipitated minerals from observed storm events was then compared with X-ray diffraction on soil clay mineralogy. The spatial distribution on both annual mean (2010) erosion rates and storm event-wise (Hurricane Otto) sediment yield among the two study watersheds were modeled using the revised and modified universal soil loss equations (RUSLE; MUSLE), respectively. Cations concentration in stream flow water samples and sediment yield were higher for the partially urbanized (Coral Bay) compared to the undisturbed (Lameshur) watershed. Our findings suggest that rural/urban development may increase stream water cations concentration and inputs of sediment to downstream ecosystems. Future studies evaluating the effect of management practices such as pavement or other stabilization of dirt roads and their impact on stream water quality and quantity and sediment yield are crucial for the proper sediment management in the study watersheds and potentially in other rural-urbanizing tropical watersheds.

Creating Safe And Healthy Neighborhoods With Place-Based Violence Interventions.

Violence is a leading cause of death and disability in the United States and abroad, with far-reaching consequences for individuals and communities. Interventions that address environmental and social contexts have the potential for greater populationwide effects, yet research has been slow to identify and rigorously evaluate these types of interventions to reduce violence. Several urban communities across the US are conducting experimental and quasi-experimental community-based research to examine the effect of place-based interventions on violence. Using examples from Philadelphia, Pennsylvania; Flint, Michigan; Youngstown, Ohio; and New Orleans, Louisiana, we describe how place-based interventions that remediate vacant land and abandoned buildings work to reduce violence. These examples support the potential for place-based interventions to create far-reaching and sustainable improvements in the health and safety of communities that experience significant disadvantage. These interventions warrant the attention of community stakeholders, funders, and policy makers.

Associations between school and neighbourhood ethnic density and physical activity in adolescents: Evidence from the Olympic Regeneration in East London (ORiEL) study.

While most adolescents do not achieve the recommended level of physical activity in the UK, the risk of physical inactivity varies across ethnic groups. We investigated whether own-group school and neighbourhood ethnic density can explain ethnic differences in adolescent physical activity. We used longitudinal data from the Olympic Regeneration in East London (ORiEL) study. In 2012, 3106 adolescents aged 11-12 were recruited from 25 schools in East London, UK. Adolescents were followed-up in 2013 and 2014. Own-group ethnic density was measured in 2012-2014 at school-level and in 2011 at neighbourhood-level, and calculated as the percentage of pupils/residents who were of the same ethnic group. Analyses were restricted to White British (n = 382), White Mixed (n = 190), Bangladeshi (n = 337), and Black African groups (n = 251). We estimated adjusted logistic regression models with generalised estimating equations for self-reported walking to school, walking for leisure, and outdoor physical activity. At school-level, there was consistent evidence that own-group ethnic density amplifies ethnic differences in walking to school. For each 10 percentage point increase in own-group ethnic density, there was evidence of increased probability of walking to school in Bangladeshi adolescents (OR = 1.20; 95% CI 1.09-1.31) and decreased probability of walking to school in Black African (OR = 0.58; 95% CI 0.45-0.75) and White Mixed adolescents (OR = 0.51; 95% CI 0.35-0.76). Associations with walking for leisure and outdoor physical activity were in expected directions but not consistently observed in all ethnic groups. At neighbourhood-level, evidence was more restricted. Amplification of ethnic differences was found for walking to school in Bangladeshi adolescents (OR = 1.31; 95% CI 1.14-1.51) and for outdoor physical activity in White British adolescents (OR = 0.85; 95% CI 0.76-0.94). Our results suggest that own-group ethnic density contributes to explaining differences in physical activity by amplifying ethnic differences in some forms of physical activity.

"Clear action requires clear thinking": A systematic review of gentrification and health research in the United States.

Gentrification is a process in which formerly declining, under-resourced, neighborhoods experience reinvestment and in-migration of increasingly affluent new residents, with understudied implications for individual health and health-protective community resources for low-income and minority residents. Increased attention on urban health inequities have propelled research on the relationship between gentrification and health. Yet, there are significant challenges inherent in the study of gentrification given its non-linear process occurring at multiple levels and via various mechanisms in a complex web of urban systems. How then have empirical studies addressed questions regarding the relationship between gentrification and health and wellness from a conceptual and methodological standpoint? Applying key search terms to PubMed and Web of Science, we identified 546 papers published in the United States. This review is guided by three foundational premises informing the inclusion and exclusion of articles. These include: 1. a clear definition of gentrification and explicit health outcome; 2. identification of a specific geographic context (United States) in which gentrification occurs, and 3. use of a social determinants of health framework to identify potential health outcomes of interest. 17 papers met our inclusion criteria. Through systematic content analysis using MaxQDA software, we evaluated the included studies using three critical frames: 1. conceptualization of gentrification; 2. mechanisms linking gentrification and health; and 3. spatio-temporal considerations. Based on this analysis, we identify the strengths and limitations of existing research, and offer three methodological approaches to strengthen the current literature on gentrification and health. We recommend that future studies: 1. explicitly identify the mechanisms and levels at which processes can occur and systems are organized; 2. incorporate space and time into the analytical strategy and 3. articulate an epistemological standpoint driven by their conceptualization of the exposure and identification of the relevant mechanism and outcome of interest.

Neighbourhood identification buffers the effects of (de-)gentrification and personal socioeconomic position on mental health.

Previous studies have suggested that the effects of gentrification on long-term residents' mental health depends upon individual socioeconomic position. However, the role of social psychological moderators of these effects remains unexplored. Drawing on the social identity approach to health, we examine whether social identification with the neighbourhood can be protective of mental health for residents in the context of (de-)gentrification. Using multi-level modelling in a longitudinal Australian sample (N = 8376), we show that neighbourhood identification protects the mental health of residents who live in neighbourhoods that undergo positive or negative neighbourhood socioeconomic status change.

Reconciling opposing perceptions of access to physical activity in a gentrifying urban neighborhood.

OBJECTIVE: We sought to understand perspectives on access to physical activity in a gentrifying neighborhood. DESIGN: This qualitative descriptive study used street intercept interviews and photo documentation. SAMPLE: Participants included members (n = 19) of a gentrifying neighborhood in a northeastern city. RESULTS: Participants held markedly different perceptions of opportunities for physical activity. Some participants, particularly area university students or those who are identified as White, perceived the neighborhood as favorable to physical activity, with high walkability and abundant resources. Other participants, particularly those who identified as Black or African-American, felt it was difficult to be physically active because neighborhood recreation facilities are scarce or unaffordable and parks are poorly maintained or unsafe. Multiple participants noted strategies to overcome neighborhood barriers to physical activity. Regardless of neighborhood perceptions, family and friends played an important role in influencing physical activity. CONCLUSIONS: Nurses must consider how disparities in actual and perceived access to neighborhood resources influence participation in physical activity, particularly in gentrifying neighborhood. Public health nurses are embedded in the neighborhoods that they serve, providing a unique opportunity to understand and address the impact of neighborhood on health.

Determining the health benefits of green space: Does gentrification matter?

Urban green space is demonstrated to benefit human health. We evaluated whether neighborhood gentrification status matters when considering the health benefits of green space, and whether the benefits are received equitably across racial and socioeconomic groups. Greater exposure to active green space was significantly associated with lower odds of reporting fair or poor health, but only for those living in gentrifying neighborhoods. In gentrifying neighborhoods, only those with high education or high incomes benefited from neighborhood active green space. Structural interventions, such as new green space, should be planned and evaluated within the context of urban social inequity and change.

Effects of changing development patterns and ignition locations within Central Texas.

Researchers have a limited understanding of the interactions between development patterns and Ignition Probability. This study explores the variation in Ignition Probability as a result of differing development patterns. Based on LANDFIRE datasets, development changes were mapped for two sets of years (2001 and 2012) and the relationship between development and Ignition Probability was assessed. The study area covered the two adjacent counties, Bastrop and Travis located in Texas, USA. These two counties have a high potential for wildfire, and due to expanding development have high vulnerability. Expanding lateral development was organized into one of five categories: infill, radial, isolated, clustered, and linear. The Maximum Entropy algorithm predicted the spatial distribution of ignition probabilities based on several physical and land use characteristics coupled with historic ignition locations. Variation in Ignition Probability was assessed for each category of development using two-way ANOVA's and post hoc analysis. Ignition Probability maps indicated a fair sensitivity (Area Under the Curve: 0.77-0.78), suggesting that the spatial configuration of development patterns influenced wildfire ignition. Analyses found that isolated, clustered, and linear outlying development patterns had higher Ignition Probability than infill and radial development, and that fire probabilities fell along a development gradient. This trend between the development gradient and ignition probabilities should be used to direct land use planning to reduce fire risk.

Mortality from Homicides in Slums in the City of Belo Horizonte, Brazil: An Evaluation of the Impact of a Re-Urbanization Project.

Background: Homicide rates in Brazil are among the highest worldwide. Although not exclusive to large Brazilian cities, homicides find their most important determinants in cities' slums. In the last decade, an urban renewal process has been initiated in the city of Belo Horizonte, in Brazil. Named Vila Viva project, it includes structuring urban interventions such as urban renewal, social development actions and land regularization in the slums of the city. This study evaluates the project's effect on homicide rates according to time and interventions. Methods: Homicide rates were analyzed comparing five slums with interventions (S1⁻S5) to five grouped non-intervened slums (S0), with similar socioeconomic characteristics from 2002 to 2012. Poisson regression model estimates the effect of time of observation and the effect of time of exposure (in years) to a completed intervention, besides the overall risk ratio (RR). Results: Using the time of observation in years, homicide rates decreased in the studied period and even more if considered cumulative time of exposure to a completed intervention for S1, S2, S3 and S4, but not for S5. Conclusions: Although the results of the effect of the interventions are not repeated in all slums, a downward trend in homicide rates has been found, which is connected to the interventions. New approaches could be necessary in order to verify the nexus between slum renewal projects and the reduction of homicide rates.