[Impacts of Urban Form on Carbon Emissions Under the Goal of Carbon Emission Peak and Carbon Neutrality: A Case Study of the Yangtze River Economic Belt].

Clarifying the mechanism of influence of urban form on carbon emissions is an important prerequisite for achieving urban carbon emission reduction. Taking the Yangtze River Economic Belt as an example, this study elaborated on the general mechanism of urban form on carbon emissions, used multi-source data to quantitatively evaluate the urban form, and explored the impacts of urban form indicators on carbon emissions from 2005 to 2020 at global and sub-regional scales with the help of spatial econometric models and geodetector, respectively. The results showed that:① The carbon emissions of the Yangtze River Economic Belt increased from 2 365.31 Mt to 4 230.67 Mt, but the growth rate gradually decreased. Its spatial distribution pattern was bipolar, with high-value areas mainly distributed in core cities such as Shanghai and Chongqing and low-value areas concentrated in the western regions of Sichuan and Yunnan. ② The area of construction land in the study area expanded over the past 15 years, but the population density of construction land had been decreasing. The degree of urban fragmentation was decreasing, and the difference between cities was also progressively narrowing. The average regularity of urban shape improved, and the compactness increased significantly. ③ All indicators of urban scale had significant positive effects on carbon emissions at the global scale, urban fragmentation had a significant negative effect in 2005, and the effective mesh size (MESH) indicator of urban compactness showed a significant negative correlation with carbon emissions in the study period. ④ Total class area, patch density, and effective mesh size had the most significant impacts on carbon emissions in upstream cities. Effective mesh size, mean perimeter-area ratio, and total class area had higher influences in midstream cities. Effective mesh size, percentage of like adjacencies, and largest patch index were the key factors to promote carbon reduction in downstream cities. Cities in different regions should comprehensively consider the impacts of various urban form indicators on carbon emissions and then optimize their urban form to promote sustainable development.

Impact of urban form and street infrastructure on pedestrian-motorist collisions.

This study examines the impact of urban form and street infrastructure on pedestrian safety in Atlanta, Georgia, and Boston, Massachusetts. With a significant rise in pedestrian fatalities over the past decade, understanding how cities' built environments influence safety is critical. We conducted geospatial analyses and statistical tests, revealing unique patterns in each city. Atlanta's sprawling, motorist-oriented layout is associated with increased pedestrian accidents, particularly at crosswalks, due to limited land use diversity, arterial roads, and streets with high speed limits and multiple lanes. In contrast, Boston's compact, pedestrian-oriented design leads to improved safety, featuring safer pedestrian crossings, greater land use diversity, reduced arterial roads and lower speed limits on single-lane streets. This study also highlights the importance of diverse urban forms and pedestrian infrastructure in shaping pedestrian safety. While population density and land use diversity impact accident rates, the presence of crosswalks and street configurations play crucial roles. Our findings underscore the urgency for urban planners to prioritize pedestrian safety through targeted interventions, such as enhancing crosswalks, reducing speed limits and promoting mixed land use. Future research should explore additional variables, alternative modelling techniques and non-linear approaches to gain a more comprehensive understanding of these complex relationships.

Dynamics of urban expansion and form changes impacting carbon emissions in the Guangdong-Hong Kong-Macao Greater Bay Area counties.

Cities are the main carriers of social and economic development, and they are also important sources of carbon emissions. Therefore, it is essential to explore the impact of urban expansion and form changes on carbon emissions. Here, we attempted to analyzes the relationship between urban expansion and carbon emissions at the county level in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) from 1997 to 2017. It further decomposes the driving effects of carbon emissions from multiple factors, and considers the spatial heterogeneity between different urban form changes and driving effects. The results show that: The relationship between urban expansion and carbon emissions in the GBA has gone through three stages from 1997 to 2017, with 2012 as a turning point. Optimization of economic development models and strict protection of the ecological environment can effectively control carbon emissions. After 2012, the economic development effect (GE) and population scale effect (PE) are the driving factors of carbon emissions, while the carbon emission intensity effect (CE) and urban land intensity effect (UE) are the inhibitory factors of carbon emissions. The contribution rate of UE to carbon emission reduction can reach 86 %. The impact of urban form changes on carbon emissions has spatial heterogeneity. The changes in urban form have a significant impact on the carbon emissions of counties in Dongguan and Shenzhen. The increase in fragmentation indirectly promotes carbon emissions. In 2007-2012, the increase in centrality significantly weakened the economic development effect, which is conducive to emission reduction. After 2007, the increase in compactness in counties in the eastern part of the GBA, including Zhongshan and Zhuhai, is not conducive to emission reduction.

Exploring the linkages between urban form, mobility and emissions with OLYMPUS: A comparative analysis in two French regions.

Nowadays, urban planners and decision-makers are confronted with an increasing number of major urban spaces whose functioning is accompanied by a high density of domestic, private and professional activities, all associated with the consumption of fossil fuels and the emission of atmospheric pollutants and greenhouse gases. As centers of activity and zones of economic and demographic resources, urban centers stand out as privileged areas for the implementation of local strategies aiming at reducing air pollutant emissions, whether through spatial planning, the evolution of services or the transformation of practices. In this work, we propose a diagnosis of the links between population, urban forms, mobility and air pollutant emissions, using the OLYMPUS activity-based emission model. The model is run over two distinct French regions, Pays de la Loire and Île-de-France, characterized by contrasting urban characteristics in terms of structure, density and accessibility. The results highlight the good transposability of the OLYMPUS model over different territories. Then, the interconnections between the specificities of urban systems on one side and the travel demand, modal share, mobility patterns and total road emissions on the other side, are explored. We notably show that the densification of urban centers exerts a pull on peri-urban areas, generating car trips from the suburbs and worsening air quality in the urban cores. The results underline the importance of targeted emission reduction strategies taking into account the unique characteristics and challenges of specific urban landscapes.

Spillover effects of urban form on urban land use efficiency: evidence from a comparison between the Yangtze and Yellow Rivers of China.

The contradiction between the basin's economic importance and its role as an ecological barrier impedes efficient urban land use. This study aims to propose an integrated approach to compare the urban land use of two representative basin areas of the Yangtze River Economic Belt and the Yellow River Basin and to investigate the impact of urban form on urban land use efficiency. Urban form was characterized by landscape indexes including Patch Density, Largest Patch Index, Edge Density, Patch Cohesion Index, and Agglomeration Index based on FRAGSTATS 4.0 software, and urban land use efficiency was measured by using Slack-Based Model-Undesirable, considering urban land becomes an emission source. Furthermore, spatial econometric models were adopted to explore direct effects and spatial spillover effects of urban form on urban land use efficiency. From 2000 to 2018, changes in urban form in both Yangtze River Economic Belt and Yellow River Basin showed increased fragmentation, enhanced heterogeneity, and more complex patch shapes. The high values of urban land use efficiency were concentrated in lower reaches of the Yangtze and Yellow Rivers. Spatial econometric models suggested that between different basins and various sized cities, the impact of urban form on urban land use efficiency had a spatial spillover effect and regional heterogeneity. Results indicated that input factors such as capital and labor should be more concentrated in metropolitan areas and urban agglomerations, thus promoting higher land use efficiency.

Urban Form Metrics for Promoting Walking: Street Layouts and Destinations.

There is evidence that higher street connectivity and availability of destinations can support walking behavior. However, the availability of data and comparability between previous studies remain a challenge. Based on a large Canadian adult sample, this study examined the associations between street layout and walking behaviors and explored whether objectively measured destinations may mediate these relationships. This study used data from 12,378 adults from Alberta's Tomorrow Project (ATP), a prospective cohort study conducted in Alberta, Canada. Walking behaviors were obtained by questionnaires. Street layout and destination measures were calculated objectively. Covariate-adjusted multivariate linear models estimated the associations between the space syntax street integration and duration of transport and leisure walking. The mediation effects of the availability of destinations in these associations were tested by the structural equation modelling. Street integration was significantly positively associated with transportation walking (b=0.01, 95% CI 0.00, 0.01, p = 0.01) (indirect effect). The availability of destinations partially mediated this association. Using the natural movement theory in space syntax, our study provides insights into using street layouts as a primary measure to (re)design the built environment to support walking.

Air pollutant dispersion around high-rise building cluster forms: the case of Port City, Colombo, Sri Lanka.

Air quality in dense urban environments is a growing concern, especially in rapidly developing cities. In the face of growing traffic associated with urbanisation, there is evidence for high levels of pollutant concentration at street level which is influenced by building forms. In this paper, we examine the potential effects of high-rise, cluster developments permitted by the local planning authorities in the newly established Port City development in Colombo, Sri Lanka. We designed possible building forms based on specific guidelines for the development in terms of plot coverage, floor area ratio, and maximum height. The three-dimensional building clusters were simulated using the RANS RNG k-epsilon turbulence model, to determine pollutant dispersion of a complex street formation in a high-dense high-rise building cluster, within the development and the surrounding context (existing Colombo). Results show that while increased porosity within the built fabric facilitates better pollution dispersion, a low correlation was seen between wind velocity and pollution concentration, especially in deep narrow high-rise canyons. Dispersion patterns at street level and at the urban canopy differed with each built form and are dependent on each canyon geometry. Thus, the study highlights the need for building regulations to take a holistic approach to capture the various elements of a complex urban cluster rather than the current two-dimensional parameters proposed for Port City, Colombo.

Assessing the impact of urban form and urbanization process on tropospheric nitrogen dioxide pollution in the Yangtze River Delta, China.

Optimizing urban form through urban planning and management policies can improve air quality and transition to demand-side control. Nitrogen dioxide (NO2) in the urban atmosphere, mainly emitted by anthropogenic sources such as industry and vehicles, is a key precursor of fine particles and ozone pollution. Both NO2 and its secondary pollutants pose health risks for humans. Here we assess the interactions between urban forms and airborne NO2 pollution in different cities with various stages of urbanization in the Yangtze River Delta (YRD) in China, by using the machine learning and geographical regression model. The results reveal a strong correlation between urban fragmentation and tropospheric NO2 vertical column density (TVCD) in YRD cities in 2020, particularly those with lower or higher levels of urbanization. The correlation coefficients (R2) between NO2 TVCD and the largest patch index (a metric of urban fragmentation) in different cities are greater than 0.8. For cities at other urbanization stages, population and road density are strongly correlated with NO2 TVCD, with an R2 larger than 0.61. This study highlights the interdependence among urbanization, urban forms, and air pollution, emphasizing the importance of customized urban landscape management strategies for mitigating urban air pollution.

Examining the impact of urban compactness on work and social life disruption during COVID-19 pandemic: evidence from Jakarta, Indonesia.

The COVID-19 pandemic has hit urban areas particularly hard, yet there is a lack of research on the hypothesis that living in more compact cities can provide better support for work and social conditions during the pandemic. This study addresses this gap by examining whether city compactness can mitigate the negative impact of the pandemic on the work and social life of urban residents in Jakarta, Indonesia. The study uses a household phone survey combined with publicly available urban form data. Ordinary Least Squares (OLS) regression, supplemented with a matching technique to address potential selection bias, is employed. The results suggest that living in more compact locations can reduce the disruption to work and social life associated with COVID-19 in urban communities. This positive effect is particularly experienced by males, non-migrants, and individuals from wealthy families.

Urban design and cardio-metabolic risk factors.

Accumulating evidence suggests that the built environment may be associated with cardiovascular disease via its influence on health behaviours. The aim of this study was to estimate the associations between traditional and novel neighbourhood built environment metrics and clinically assessed cardio-metabolic risk factors among a sample of adults in Canada. A total of 7171 participants from Albertas Tomorrow Project living in Alberta, Canada, were included. Cardio-metabolic risk factors were clinically measured. Two composite built environment metrics of traditional walkability and space syntax walkability were calculated. Among men, space syntax walkability was negatively associated with systolic and diastolic blood pressure (b = -0.87, 95% CI -1.43, -0.31 and b = -0.45, 95% CI -0.86, -0.04, respectively). Space syntax walkability was also associated with lower odds of overweight/obese among women and men (OR = 0.93, 95% CI 0.87, 0.99 and OR = 0.88, 95% CI 0.79, 0.97, respectively). No significant associations were observed between traditional walkability and cardio-metabolic outcomes. This study showed that the novel built environment metric based on the space syntax theory was associated with some cardio-metabolic risk factors.

Study on the mechanism of urban morphology on river cooling effect in severe cold regions.

In the context of global warming, urban climate problems such as heat waves, urban heat islands and air pollution are becoming increasingly prominent, and the cooling effect of rivers is an effective way to mitigate urban hot climate. This study investigates the surrounding urban area of the Hun River in Shenyang, a severe cold region of China, by calculating satellite inversion surface temperature and urban morphology data, and explores the cooling effect of rivers using linear regression models and spatial regression models. The results show that (1) water bodies have a cooling effect on the surrounding environment, with the farthest cooling distance being 4,000 m, but the optimal cooling distance being 2,500 m. (2) In the results of the spatial regression model analysis, the R 2 value stays above 0.7 in the range of 0-4,000 m, indicating that urban morphological factors are closely related to LST (land surface temperature). The negative correlation is most pronounced for NVDI (normalized vegetation index), with a peak of -14.8075 calculated by the regression model, and the positive correlation is most pronounced for BD (building density), with a peak of 8.5526. (3) The urban thermal environment can be improved and the heat island effect mitigated through measures such as increasing urban vegetation cover and reducing building density, and these findings can provide data references and case studies to support urban planning and development departments.

Effects of land-use change on carbon emission and its driving factors in Shaanxi Province from 2000 to 2020.

Exploring the process of carbon emissions under the "carbon peaking and carbon neutrality goals" can contribute to sustainable economic development. This research takes Shaanxi Province as an example. We elaborated on the spatial and temporal characteristics of land-use change from 2000 to 2020 and adopted the carbon emission model method to calculate land-use carbon emissions, also used urban morphological indicators to reveal the main factors of carbon emission changes. The results show that from 2000 to 2020, the land-use change in Shaanxi Province is mainly reflected in the increase in construction land area and the decrease in agricultural land area. Among them, the construction land area increased by 2192 km2, and the agricultural land area decreased by 5006 km2. Land-use carbon emissions increased by 1.28 × 1011 kg during this period. Construction land is a major contributor to carbon emissions. The forestland is the main carbon sink. Carbon emissions showed a spatial pattern of "high in the north, low in the south, and concentrated in the middle." Urban form change is the driving factor affecting land-use carbon emissions in Shaanxi Province. The results of the research contribute to the understanding of regional carbon emission mechanisms and provide a scientific basis for reducing carbon emissions.

Exploring the regional differences of ecosystem health and its spatial relationships with urban forms in China.

A deeper understanding of the regional differences and driving factors behind ecosystem health (EH) is of vital for ecosystem management and restoration. Although a considerable number of studies have focused on this topic, few studies have explored the spatial relationship and scale effect between urban forms and EH from the perspective of urban scale, agglomeration and irregularity. Therefore, this study first constructed an improved evaluation framework by integrating vigor, organization, resilience and ecosystem services supply-demand ratio to measure the EH level in China at the county scale during 1995-2015, and then evaluated and compared the spatial relationships between five urban form metrics and EH based on the spatial regression model at the national, regional, urban agglomeration and city scales. The results showed that the level of EH in China spatially decreased from the southeast to the northwest, and displaying significant spatial agglomeration. At the national scale, the fragmentation and complexity of urban form exerted the greater negative influence on EH than urban expansion scale. At the regional scale, controlling urban expansion scale and enhancing landscape connectivity were conducive to the improving of EH in the central and eastern regions. At the urban agglomeration scale, the regularity and compactness of urban form played a key role in the sustainable development of regional and national urban agglomerations. At the city scale, large cities can improve environmental quality by limiting the size of core patches and reducing the complexity of urban shape. This paper can provide a scientific guidance for ecosystem protection and urban high-quality development.

A gridded dataset on densities, real estate prices, transport, and land use inside 192 worldwide urban areas.

This work presents a gridded dataset on real estate and transportation in 192 worldwide urban areas, obtained from the Google Maps API and the web scraping of real estate websites. For each city of the sample, these data have been associated with the corresponding population density and land cover data, extracted from the GHS POP and ESA CCI data respectively, and aggregated on a 1 km resolution grid, allowing for an integrated analysis. This dataset is the first to include spatialized real estate and transportation data in a large sample of cities covering 800 million people in both developed and developing countries. These data can be used as inputs for urban modeling purposes, transport modeling, or between-city comparisons in urban forms and transportation networks, and allow further analyses on e.g. urban sprawl, access to transportation, or equity in housing prices and access to transportation.

Variation in youth and young adult homicide rates and their association with city characteristics in Latin America: the SALURBAL study.

Background: Latin America and the Caribbean (LAC) is one of the most urbanized and violent regions worldwide. Homicides in youth (15-24 years old, yo) and young adults (25-39yo) are an especially pressing public health problem. Yet there is little research on how city characteristics relate to homicide rates in youth and young adults. We aimed to describe homicide rates among youth and young adults, as well as their association with socioeconomic and built environment factors across 315 cities in eight LAC countries. Methods: This is an ecological study. We estimated homicide rates in youth and young adults for the period 2010-2016. We investigated associations of homicide rates with sub-city education and GDP, Gini, density, landscape isolation, population and population growth using sex-stratified negative binomial models with city and sub-city level random intercepts, and country-level fixed effects. Findings: The mean sub-city homicide rate per 100,000 in persons aged 15-24 was 76.9 (SD = 95.9) in male and 6.7 (SD = 8.5) in female, and in persons aged 25-39 was 69.4 (SD = 68.9) in male and 6.0 (SD = 6.7) in female. Rates were higher in Brazil, Colombia, Mexico and El Salvador than in Argentina, Chile, Panama and Peru. There was significant variation in rates across cities and sub-cities, even after accounting for the country. In fully adjusted models, higher sub-city education scores and higher city GDP were associated with a lower homicide rate among male and female (rate ratios (RR) per SD higher value in male and female, respectively, 0.87 (CI 0.84-0.90) and 0.90 (CI 0.86-0.93) for education and 0.87 (CI 0.81-0.92) and 0.92 (CI 0.87-0.97) for GDP). A higher city Gini index was associated with higher homicide rates (RR 1.28 (CI 1.10-1.48) and 1.21 (CI 1.07-1.36) in male and female, respectively). Greater isolation da was also associated with higher homicide rates (RR 1.13 (CI 1.07-1.21) and 1.07 (CI 1.02-1.12) in male and female, respectively). Interpretation: City and sub-city factors are associated with homicide rates. Improvements to education, social conditions and inequality and physical integration of cities may contribute to the reduction of homicides in the region. Funding: The Wellcome Trust [205177/Z/16/Z].

Seeking the Nexus Between Building Acoustics and Urban Form: A Systematic Review.

Purpose of Review: Noise is penetrating urban life pervasively and is imperative for demonstrating the factors behind it regarding built environment, aka buildings and urban form. So, this review aims to provide a better understanding of the association between building acoustics and urban form characteristics. Recent Findings: There is a growing attention for building acoustics, including materials and simulation aspects with various increasing urban form attributes, i.e., the built and natural environment and transportation. Summary: Building acoustics is a key aspect of urban life and falls within the interface of various urban form characteristics. While these two main attributes are not sufficiently addressed, they may adversely affect individuals; thus, all the more reason to explore this nexus. This study has evaluated 67 peer-reviewed journal articles after systematically reviewing the triple resources in assessing building acoustics and urban form between 2016 and 2022. This review separates the indoor and outdoor categories within the simulation, theory, building materials, facade, and the built environment sub-categories. The study does not only review the overall scope of present studies but also direct future directions of their associations.

Scaling of the morphology of African cities.

A large proportion of Africa's infrastructure is yet to be built. Where and how these new buildings are constructed matters since today's decisions will last for decades. The resulting morphology of cities has lasting implications for a city's energy needs. Estimating and projecting these needs has always been challenging in Africa due to the lack of data. Yet, given the sweeping urbanization expected in Africa over the next three decades, this obstacle must be overcome to guide cities toward a trajectory of sustainability and resilience. Based on the location and surface of nearly 200 million buildings on the continent, we estimate the interbuilding distance of almost six thousand cities. Buildings' footprint data enable the construction of urban form indicators to compare African cities' elongation, sprawl, and emptiness. We establish the BASE model, where the mean distance between buildings is a functional relation to the number of Buildings and their average Area, as well as the Sprawl and the Elongation of its spatial arrangement. The mean distance between structures in cities-our proxy for its energy demands related to mobility-grows faster than the square root of its population, resulting from the combined impact of a sublinear growth in the number of buildings and a sublinear increase in building size and sprawl. We estimate that when a city doubles its population, it triples its energy demand from transport.

Categorizing relative water use perception bias using household surveys and monthly water bills.

We introduce the concept of relative water use perception bias to highlight the role of human relationships, social cues, and the built environment in household water consumption. Although previous studies have explored actual water use, it is also important to understand how people perceive their relative behaviors because humans are social animals and act in relation to each other. We combine household survey responses and water utility bills in a large sample of households to quantify the degree of over- and under-estimation bias in perceived relative household water use. We then use multi-level nested regression models to investigate four categories of potential influence: sociodemographic characteristics, perceived social norms, neighborhood characteristics, and water bill information. Results show that most households tended to view themselves as 'better than average' water users when they actually used more water compared to neighbors. Respondents in high-income households and those who are more concerned about water shortages were more likely to underestimate their relative water use (using comparatively more than they thought). However, in more suburbanized neighborhood environments, households were more likely to overestimate their relative water use (using comparatively less than they thought). We call the inaccuracy in assessing water usage compared to their neighbors' relative water use perception bias. We propose that a better understanding of this bias can aid the design of policy initiatives like neighborhood planning, better water bill design, targeted messaging, and social signaling. By bringing a relational lens to bear on water conservation studies, understanding relative water use perception bias sheds new light on the complex drivers of household water consumption.

Reconsidering the effects of urban form on PM2.5 concentrations: an urban shrinkage perspective.

The phenomenon of urban shrinkage is currently occurring worldwide; however, the "growth-oriented" planning paradigm is not suitable for these shrinking cities. Reconsidering the relationship between urban form and PM2.5 concentrations from the perspective of urban shrinkage can help provide a research reference for controlling air pollution and optimizing the spatial layout of shrinking cities. This study takes shrinking areas in China as the research subject, which are divided into four research groups according to their shrinkage degree. The empirical results indicate that the average PM2.5 concentrations decrease with the aggravation of urban shrinkage. In terms of the effect of urban form on PM2.5 concentrations, the urban size is always positively related to PM2.5 concentrations, while the impact of urban fragmentation on PM2.5 concentrations is negligible. Further, urban shape positively affects PM2.5 concentrations only in moderately and severely shrinking cities. Cities with sprawling urban forms have higher PM2.5 concentrations, except for those facing severe shrinking trends. This study suggests that governments in shrinking cities should reasonably adjust both the urban form and land use to improve air quality based on the degree of urban shrinkage.

Built environment influences on urban climate resilience: Evidence from extreme heat events in Macau.

Systematic understanding of climate resilience in the urban context is essential to improve the adaptive capacity in response to extreme weather events. Although the urban built environment affects climate resilience, empirical evidence on the associations between the built environment and urban climate resilience is rare in the literature. In this study, urban heat resilience (HR) is measured as the land surface temperature (LST) difference in a given urban area between normal and extreme heat event, and it further explores the impact of two-dimensional (2D) and three-dimensional (3D) urban built environment features on HR. Using spatial regression, we find that solar insolation and water density are the dominant factors in determining land surface temperature. However, they do not appear to influence HR significantly. Results indicate that vegetation and urban porosity are crucial both in reducing LST and improving HR during extreme heat events. This study highlights the importance of 2D and 3D urban built environment features in improving HR to extreme heat events.