Urban form and extreme heat events: are sprawling cities more vulnerable to climate change than compact cities?

Heat-Related Health Risks for People Experiencing Homelessness: A Rapid Review

Extreme heat poses a significant public health threat for people experiencing homelessness (PEH), who face heightened risks due to prolonged outdoor exposure and limited access to resources. This rapid review synthesizes research from the past five years on the health impacts of extreme heat for PEH in high-income countries. A total of 11 studies were identified through a systematic search of multiple databases, focusing on publications from 2019 to 2024. The review highlights key vulnerability factors, including demographic characteristics, pre-existing health conditions, and geographic disparities, that increase heat-related health risks for PEH. Physical health impacts, such as heat-related morbidity and mortality, are common, alongside mental health and substance use disorders exacerbated by heat exposure. The review also highlights a significant increase in emergency department visits among PEH during heat events, emphasizing the additional burden on healthcare systems. Barriers, including limited physical and social access to cooling centers, water insecurity, and stigma, further compound these challenges. Addressing the unique vulnerabilities of PEH is crucial to reducing their risks during extreme heat events. Improving housing access and stability is essential as a long-term strategy to decrease homelessness and reduce heat stress in this vulnerable population. The review also underscores the need for inclusive interventions such as accessible cooling centers with targeted programming, regular access to water, and tailored healthcare services to meet the needs of PEH. Future research should focus on long-term studies to assess potential cumulative heat exposure effects and evaluate the effectiveness of interventions aimed at mitigating extreme heat impacts on PEH, while applying an intersectionality lens to explore how factors like race, gender, and age shape vulnerabilities and potential intervention strategies.

Corrigendum to 'Extreme temperature increases the risk of COPD morbimortality: A systematic review and meta-analysis [Science of The Total Environment, Vol 958 [2025] 178087'

INTRODUCTION

This systematic review examines how extreme temperatures impact Chronic Obstructive Pulmonary Disease (COPD) morbidity and mortality, focusing on identifying vulnerable subpopulations.

METHODS

We conducted a systematic literature search from January 1, 2000, to November 6, 2024, across databases like PubMed, MEDLINE and EMBASE, Web of Science, and Scopus, focusing on observational studies that quantitatively defined extreme temperatures and their impacts on COPD morbidity and mortality. Out of 3140 records, 25 studies met the inclusion criteria. We extracted data on study characteristics, effect estimates, and confounders, employing methods to assess the risk of bias and synthesize results.

RESULTS

We observed that extreme heat increased the relative risk (RR) for COPD morbimortality by 1.19-fold (95 % CI: 1.09-1.29; p < 0.05), and extreme cold increased the RR by 1.35-fold (95 % CI: 1.22-1.50; p < 0.05). Extreme heat was associated with a 1.23-fold (95 % CI: 1.11-1.35; p < 0.05) increase in COPD mortality. In contrast, extreme cold was associated with both COPD morbidity and mortality, with morbidity increasing by 1.47-fold (95 % CI: 1.26-1.71; p < 0.05) and mortality by 1.28-fold (95 % CI: 1.12-1.45; p < 0.05). Extreme heat poses a higher risk for female COPD patients compared to males. Moreover, extreme heat and cold were associated with morbimortality risk among older adults. Asian populations were sensitive to both temperature extremes, whereas Europeans were predominantly susceptible to extreme cold.

CONCLUSION

This variability in response to extreme temperatures affects COPD morbidity and mortality, emphasizing the need for tailored medical and emergency responses to effectively mitigate health risks during extreme weather events.

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

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

Comorbidities, Tobacco Exposure, and Geography: Added Risk Factors of Heat and Cold Wave-related Mortality among U.S. Veterans with Chronic Obstructive Pulmonary Disease

Rationale: Understanding the health risks associated with extreme weather events is needed to inform policies to protect vulnerable populations. Objectives: To estimate heat and cold wave-related mortality risks in a cohort of veteran patients with chronic obstructive pulmonary disease (COPD) and explore disparities among strata of comorbidities, tobacco exposure, and urbanicity. Methods: We designed a time-stratified case-crossover study among deceased patients with COPD between 2016 and 2021 in the Veterans Health Administration system. Distributed lag models with conditional logistic regression estimated incidence rate ratios of heat and cold wave-associated mortality risk from lag days 0 to 3 for heatwaves and lag days 0 to 7 for cold waves. Attributable risks (ARs) per 100,000 patients were also calculated. Results: Of the 377,545 deceased patients with COPD, the largest heatwave-related mortality risk was in patients with COPD and asthma (AR, 14,016; 95% confidence interval [CI], -326, 30,706) across lag days 0 to 3. The largest cold wave-related mortality burden was in patients with COPD with no other reported comorbidities (AR, 1,704; 95% CI, 759, 2,686) across lag days 0 to 7. Patients residing in urban settings had the greatest heatwave-related (AR, 1,062; 95% CI, 576, 1,559) and cold wave-related (AR, 1,261; 95% CI, 440, 2,105) mortality risk (across lag days 0 to 1 and 0 to 7, respectively). There were no differences in mortality risk by tobacco exposure. Conclusions: Our findings show that individuals with COPD are susceptible to heat and cold waves. This information can inform clinical practice and public health policy about the mortality risk vulnerable populations experience with respect to extreme weather conditions. Furthermore, our results may be used in the development and refinement of future extreme weather warning systems designed for public health purposes.

Adaptation in the Alleyways: Candidate Genes Under Potential Selection in Urban Coyotes

In the context of evolutionary time, cities are an extremely recent development. Although our understanding of how urbanization alters ecosystems is well developed, empirical work examining the consequences of urbanization on adaptive evolution remains limited. To facilitate future work, we offer candidate genes for one of the most prominent urban carnivores across North America. The coyote (Canis latrans) is a highly adaptable carnivore distributed throughout urban and nonurban regions in North America. As such, the coyote can serve as a blueprint for understanding the various pathways by which urbanization can influence the genomes of wildlife via comparisons along urban-rural gradients, as well as between metropolitan areas. Given the close evolutionary relationship between coyotes and domestic dogs, we leverage the well-annotated dog genome and highly conserved mammalian genes from model species to outline how urbanization may alter coyote genotypes and shape coyote phenotypes. We identify variables that may alter selection pressure for urban coyotes and offer suggestions of candidate genes to explore. Specifically, we focus on pathways related to diet, health, behavior, cognition, and reproduction. In a rapidly urbanizing world, understanding how species cope and adapt to anthropogenic change can facilitate the persistence of, and coexistence with, these species.

Extreme temperature increases the risk of COPD morbimortality: A systematic review and meta-analysis

INTRODUCTION

This systematic review examines how extreme temperatures impact chronic obstructive pulmonary disease (COPD) morbidity and mortality, focusing on identifying vulnerable subpopulations.

METHODS

We conducted a systematic literature search from January 1, 2000, to November 6, 2024, across databases like PubMed, MEDLINE and EMBASE, Web of Science, and Scopus, focusing on observational studies that quantitatively defined extreme temperatures and their impacts on COPD morbidity and mortality. Out of 3140 records, 25 studies met the inclusion criteria. We extracted data on study characteristics, effect estimates, and confounders, employing methods to assess the risk of bias and synthesize results.

RESULTS

We observed that extreme heat increased the relative risk (RR) for COPD morbimortality by 1.16-fold (95 % CI: 1.08-1.26; p < 0.05), and extreme cold increased the RR by 1.32-fold (95 % CI: 1.20-1.46;). Extreme heat was associated with a 1.19-fold (95 % CI: 1.09-1.30; p < 0.05) increase in COPD mortality. In contrast, extreme cold was associated with both COPD morbidity and mortality, with morbidity increasing by 1.47-fold (95 % CI: 1.26-1.71; p < 0.05) and mortality by 1.23-fold (95 % CI: 1.10-1.38; p < 0.05). Extreme heat poses a higher risk for female COPD patients compared to males. Moreover, extreme heat and cold were associated with morbimortality risk among older adults. Asian populations were sensitive to both temperature extremes, whereas Europeans were predominantly susceptible to extreme cold.

CONCLUSION

This variability in response to extreme temperatures affects COPD morbidity and mortality, emphasizing the need for tailored medical and emergency responses to effectively mitigate health risks during extreme weather events.

Combating urban heat: Systematic review of urban resilience and adaptation strategies

Urban areas are currently facing the increasingly pressing issue of urban heat worldwide, which is being worsened by climate change and rising urbanization. As a result, there is a growing need for new approaches to enhance urban resilience and adapt to these challenges. The escalating occurrence and severity of urban heat events provide notable hazards, particularly to susceptible groups, necessitating proactive efforts to alleviate detrimental consequences. Therefore, this research addresses the inquiry, "What strategic approaches can be effectively employed to mitigate vulnerability and strengthen urban resilience in response to urban heat?" Thus, this study ascertains and examines approaches to enhance urban resilience, mitigate susceptibility, and implement adaptation strategies to combat urban heat. Utilizing the content analysis method, a comprehensive assortment of documents encompassing academic publications, policy documents, and reports was subjected to a systematic analysis employing the MAXQDA software. Databases searched included Web of Science, Scopus, and Google Scholar, and a total of 72 studies were included in the final analysis. The research reveals a wide range of novel ideas and practical measures that can be implemented to improve urban resilience and mitigate vulnerability to urban heat. Urban greening strategies, heatwave early warning sys-tems, and community involvement projects have exhibited differing effectiveness, application, and adaptation levels in many urban landscapes and socio-economic circumstances. Additionally, this research emphasizes the value of using multidimensional, context-specific strategies to address the unique challenges and needs of diverse urban regions and marginalized communities. Furthermore, structural changes, legislative reforms, and community-based solutions may be necessary to manage complex issues posed by urban heat. Therefore, effectively implementing adaptation strategies is vital to effectively combating challenges caused by urban heat in urban areas.

The impact of urban configuration types on urban heat islands, air pollution, CO2 emissions, and mortality in Europe: a data science approach

BACKGROUND

The world is becoming increasingly urbanised. As cities around the world continue to grow, it is important for urban planners and policy makers to understand how different urban configuration patterns affect the environment and human health. However, previous studies have provided mixed findings. We aimed to identify European urban configuration types, on the basis of the local climate zones categories and street design variables from Open Street Map, and evaluate their association with motorised traffic flows, surface urban heat island (SUHI) intensities, tropospheric NO2, CO2 per person emissions, and age-standardised mortality.

METHODS

We considered 946 European cities from 31 countries for the analysis defined in the 2018 Urban Audit database, of which 919 European cities were analysed. Data were collected at a 250 m × 250 m grid cell resolution. We divided all cities into five concentric rings based on the Burgess concentric urban planning model and calculated the mean values of all variables for each ring. First, to identify distinct urban configuration types, we applied the Uniform Manifold Approximation and Projection for Dimension Reduction method, followed by the k-means clustering algorithm. Next, statistical differences in exposures (including SUHI) and mortality between the resulting urban configuration types were evaluated using a Kruskal-Wallis test followed by a post-hoc Dunn's test.

FINDINGS

We identified four distinct urban configuration types characterising European cities: compact high density (n=246), open low-rise medium density (n=245), open low-rise low density (n=261), and green low density (n=167). Compact high density cities were a small size, had high population densities, and a low availability of natural areas. In contrast, green low density cities were a large size, had low population densities, and a high availability of natural areas and cycleways. The open low-rise medium and low density cities were a small to medium size with medium to low population densities and low to moderate availability of green areas. Motorised traffic flows and NO2 exposure were significantly higher in compact high density and open low-rise medium density cities when compared with green low density and open low-rise low density cities. Additionally, green low density cities had a significantly lower SUHI effect compared with all other urban configuration types. Per person CO2 emissions were significantly lower in compact high density cities compared with green low density cities. Lastly, green low density cities had significantly lower mortality rates when compared with all other urban configuration types.

INTERPRETATION

Our findings indicate that, although the compact city model is more sustainable, European compact cities still face challenges related to poor environmental quality and health. Our results have notable implications for urban and transport planning policies in Europe and contribute to the ongoing discussion on which city models can bring the greatest benefits for the environment, climate, and health.

FUNDING

Spanish Ministry of Science and Innovation, State Research Agency, Generalitat de Catalunya, Centro de Investigación Biomédica en red Epidemiología y Salud Pública, and Urban Burden of Disease Estimation for Policy Making as a Horizon Europe project.

Spatial congruency or discrepancy? Exploring the spatiotemporal dynamics of built-up expansion patterns and flood risk

Most coastal cities have been experiencing unprecedented urbanization-induced flood risk, climatic events, and haphazard anthropogenic activities, jeopardizing residents' lives and building environments. Despite mounting flood-related studies, analyzing the correlation between the spatiotemporal dynamics of Built-up Expansion patterns (BE) and flood risk remains unknown and holds divergent perspectives. In this context, the coastal city of Alexandria, Egypt, characterized by multiple urban patterns and experiencing heavy rainfall annually, was selected as a testbed. Our method defined the spatiotemporal rates of BE from 1995 to 2023, quantified flood risk spatially, and finally investigated the correlation between BE and flood risk through spatial and statistical analysis. Our results show the built-up area occupied 30.32 % of the total city area till 2023, and the infilling pattern dominated the BE growth by 45.21 % of the total built-up area, followed by leapfrogging and edge expansion by 33.25 % and 21.55 %, respectively. The unplanned-infilling pattern is predominantly highly correlated with the flood-vulnerable peaks (correlation coefficient (rk) = 0.975, p-value < 0.05) and lowers dramatically towards planned-infilling regions with flood protections. Meanwhile, a spatial mismatch exists between high-risk peaks and leapfrogging and edge expansion (rk = 0.118 and 0.662, respectively, with a p-value < 0.01), indicating that controlling the built-up amount is inadequate for mitigating flood risk. Porosity-based urban configuration and spatial distribution of built-up patches in harmony with nature-based solutions are recommended for shaping flood-resilient and effective urban planning.

Review of emerging contaminants in green stormwater infrastructure: Antibiotic resistance genes, microplastics, tire wear particles, PFAS, and temperature

Green stormwater infrastructure is a growing management approach to capturing, infiltrating, and treating runoff at the source. However, there are several emerging contaminants for which green stormwater infrastructure has not been explicitly designed to mitigate and for which removal mechanisms are not yet well defined. This is an issue, as there is a growing understanding of the impact of emerging contaminants on human and environmental health. This paper presents a review of five emerging contaminants - antibiotic resistance genes, microplastics, tire wear particles, PFAS, and temperature - and seeks to improve our understanding of how green stormwater infrastructure is impacted by and can be designed to mitigate these emerging contaminants. To do so, we present a review of the source and transport of these contaminants to green stormwater infrastructure, specific treatment mechanisms within green infrastructure, and design considerations of green stormwater infrastructure that could lead to their removal. In addition, common removal mechanisms across these contaminants and limitations of green infrastructure for contaminant mitigation are discussed. Finally, we present future research directions that can help to advance the use of green infrastructure as a first line of defense for downstream water bodies against emerging contaminants of concern.

Compact City: What Is the Extent of Our Exploration for Its Meanings? A Systematic Review

The compact city has garnered significant attention from researchers in academia, particularly in recent years, due to its relevance to various global challenges, such as climate change, COVID-19, economic crises, and urbanization. Given the vast knowledge represented in the compact city literature and its diverse perspectives, this study aims is a comprehensive literature review through bibliometric analysis. Following the PRISMA protocol, a total of 570 articles from the Scopus database published in English between 1973 and 2022 underwent screening at two main levels of bibliometric analysis: performance analysis and science mapping. The findings of this study reveal a substantial increase in scientific production related to the compact city over the years. Furthermore, the concept of the compact city encompasses multiple dimensions, with a significant emphasis on the urban dimension. Remarkably, Asian countries (regions), particularly mainland China and China-Hong Kong, demonstrate a notable interest in the compact city concept. In conclusion, this study provides valuable insights into the scientific production of compact city literature, highlighting its growth, multidimensionality, and geographic focus, which can inform future research and policymaking efforts.

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.

Designing pandemic resilient cities: Exploring the impacts of the built environment on infection risk perception and subjective well-being

Since the beginning of the COVID-19 pandemic, authorities around the world explored ways to slowdown the spread of the disease while maintaining the physical and mental health of individuals. They redistributed the street space to promote physical activity and non-motorized travel while meeting the social distancing requirements. Although the statistics showed significant increases in walking and bicycling trips during the pandemic, we have limited knowledge about the associations between built environment characteristics, COVID-19 infection risk perception while traveling, and subjective well-being. This study assesses the impacts of the built environment on subjective well-being and infection risk perception while traveling during the pandemic. It uses data collected from the residents of Columbus, Ohio, through a multi-wave survey conducted at different time points during the COVID-19 outbreak. By employing a structural equation modeling approach, it explores the associations between residential neighborhood characteristics, individuals' subjective well-being, and perceived infection risk while using non-motorized modes and shared micromobility. The findings show that those living in more compact, accessible, and walkable neighborhoods are less likely to perceive active travel and shared micromobility as risky in terms of COVID-19 infection. Our results also show that built environment characteristics have an indirect positive effect on the subjective well-being of individuals. The findings of our study demonstrate that built environment interventions can help promote physical activity and support mental health of individuals at this critical time. Our study also indicates that designing compact neighborhoods will be a crucial element of pandemic resilient cities in the post-COVID-19 era.

COVID19 in Latin America: informal settlements and the politics of urbicide

Informal settlements in Latin America express pandemic idiosyncrasies, calling global attention to historical problems related to a specific urbanization pattern. This article stresses COVID19 implications in the main urban planning canon: the notion of densification as an urban solution. Traditionally invisible social groups and territories acquire relevance, but now as a source of biological risk. Urban density appears as a contradictory trigger point, outlining new debates about informal settlements and their metrics. Evidence shows that trends in health discourse are striving to legitimize and enhance "urbicides" in this scenario, already underway through State action or inaction.

Evidence of alliesthesia during a neighborhood thermal walk in a hot and dry city

Designing cities for thermal comfort is an important priority in a warming and urbanizing world. As temperatures in cities continue to break extreme heat records, it is necessary to develop and test new approaches capable of tracking human thermal sensations influenced by microclimate conditions, complex urban geometries, and individual characteristics in dynamic settings. Thermal walks are a promising novel research method to address this gap. During a thermal walk in Phoenix, Arizona, USA, we examined relationships between the built environment, microclimate, and subjective thermal judgments across a downtown city neighborhood slated for redevelopment. Subjects equipped with GPS devices participated in a 1-hour walk on a hot sunny day and recorded their experience in a field guide. Microclimate measurements were simultaneously collected using the mobile human-biometeorological instrument platform MaRTy. Results revealed significant differences in physiologically equivalent temperature (PET) and modified physiologically equivalent temperature (mPET) and between street segments with more than 18 °C (25 °C mPET) between the maximum and minimum values. Wider range of mPET values reflected the inclusion of individual level data into the model. Streets with higher sky view factor (SVF) and east-west orientation showed a higher PET and mPET overall. Furthermore, we showed evidence of thermal alliesthesia, the pleasure resulting from slight changes in microclimate conditions. Participants' sense of pleasure was related to the mean PET of the segment they just walked, with linear regression explaining over 60% of the variability. We also showed that estimated percent shade was significantly correlated with SVF, PET, mPET, and pleasure, indicating that participants could sense minor changes in microclimate and perceived shade as pleasant. Although generalization of results is limited by a low sample size, findings of this study improve the understanding of dynamic thermal comfort in complex urban environments and highlight the value of thermal walks as a robust research method.

Associations of Urban and Green Land Covers and Heat Waves in 49 U.S. Cities between 1992 and 2019

The study aimed to examine how changing land use conditions are related to the occurrence of heat waves. The employed methods were (1) the Urban Expansion Intensity Index (UEII) and the Green Expansion Intensity (GEII) for 49 cities in the U.S. between 1992 and 2019; (2) Spearman correlation analyses of heat wave indicators including frequency, season, duration, and intensity for UEII, and GEII, respectively. Major findings include the following: (1) urban areas have increased rapidly with an average UEII value of 1.5; (2) green Areas have increased at a slow pace, which have a GEII average value of 0.017, where the median value is −0.1, meaning the green area is declining in most U.S. cities; (3) The UEII and heat wave duration show a negative relationship with a significant correlation (γs = −0.296 and ρ = 0.04); (4) UEII and heat wave intensity show a positive relationship with a significant correlation (γs = 0.32 and ρ = 0.027). It was found that heat wave intensity can be a public health issue in high urban expansion intensity areas. The results imply that cities would be better in a more compact pattern with more expanded green areas to mitigate the negative health impacts of heat waves on citizens in urban areas. It is noticeable that there are some patterns to be investigated further in the context of urban developments and heat wave characteristics.

Influences of landform and urban form factors on urban heat island: Comparative case study between Chengdu and Chongqing

Although the degraded urban thermal environment has been widely concerned, whether monocentric or polycentric urban development can alleviate urban heat island (UHI) is still debatable, particularly considering different types of cities in plain and mountainous settings. To fill the gap, this study chose the cases of Chengdu on alluvial flatlands and Chongqing on mountainous landforms in China for comparison. Adapting to natural landforms, Chengdu has a dominated monocentric urban form, whereas Chongqing has a naturally polycentric urban form. This study found that areas with high UHI intensity were located in the urban center and peripheral suburbs in Chengdu, while those were located in the peripheral industrial zones in Chongqing. The spatial error model and random forest regression results showed that natural elements such as vegetation and water had similar influences and contributions to UHI. However, distinct landforms and urban forms played critical roles in UHI differences among the two cities. Impervious surface and building density were the dominant variables to UHI of Chengdu, while sky view factor and industrial zones were the main contributors to UHI of Chongqing. The findings called for corresponding policy strategies to optimize urban form and improve the urban thermal environment.

The Influence Mechanism of Urban Spatial Structure on Urban Vitality Based on Geographic Big Data: A Case Study in Downtown Shanghai

How can we construct the multidimensional evaluation framework of urban vitality from the perspective of urban spatial structure? Under the current intensity of land development, does the population density in the downtown area of Shanghai have the potential to be improved? Can a subdistrict be an appropriate spatial scale for evaluating urban vitality in central Shanghai? First, based on multisource geospatial big data, a comprehensive theoretical framework of the influence mechanism of urban spatial structure on urban vitality was constructed from the three dimensions of population, land use, and traffic, and 11 indicators were selected to form an evaluation index system. Second, the influence mechanism of urban spatial structure on urban vitality was analyzed from the six aspects of economic vitality, cultural vitality, quality of life, social governance, air quality, and nocturnal vitality, using binary spatial correlation analysis and a regression model based on eigenvector space filtering (ESF). The results show the following: (1) According to the combined impact analysis, the job–housing balance degree, floor area ratio, open space ratio, and road network density are positively correlated with urban vitality, while population density, land use mix degree, average block area, rail transit station density, and rail transit station accessibility are negatively correlated with urban vitality. (2) The correlation between population density and the urban comprehensive vitality index is related to the floor area ratio. Under the current land development intensity, the population density of the central urban area of Shanghai has approached the theoretical “ceiling”. (3) Different spatial scales have different effects on urban vitality. Finally, some policy suggestions are proposed to optimize the urban spatial structure and enhance urban vitality.

District-based urban expansion monitoring using multitemporal satellite data: application in two mega cities

Urban expansion is a process of urban development as a result of population growth. Urban sprawl, known as unplanned and unrestricted urban expansion, is among the most important topics in urban studies. In recent decades, many cities around the world in both developing and developed countries have experienced urban expansion. Istanbul and Sydney are two of those cities encountering the urban expansion. Thus, in this study, the spatial and temporal pattern of urban expansion of the most urbanized districts of Istanbul (Arnavutköy) and Sydney (Hills Shire) was analyzed using multi-temporal remote sensing data. Initially, the Landsat images were classified to evaluate the land use/land cover (LULC) changes. The change detection analysis revealed that urban area of Arnavutköy district has increased about 669% from 1997 to 2017 and urban area of Hills Shire Local Government Area (LGA) increased by 78% between 1996 and 2018. The relationship of land surface temperature (LST) and urban areas extracted by recoding the LULC maps was also evaluated in different buffer zones. The results showed that with the increase in urban area extent, the LST has also increased. Then, Shannon's entropy and spatial landscape metrics were used to analyze the district-based urban expansion. The results showed that both study areas expanded over the time but the main differences observed are that Arnavutköy has more fragmented and Hills Shire has a more compact urban growth process.

Impact of Climate Change on Rural Poverty Vulnerability from an Income Source Perspective: A Study Based on CHIPS2013 and County-Level Temperature Data in China

Harsh natural climatic environments, such as extreme weather and natural disasters, cause devastating blows to production activities and increase the probability of geographic poverty, climate poverty, and return to poverty. Thus, this study uses climate data and micro survey data (CHIPS2013) to examine the impact of climate on vulnerability to individual poverty in rural China. The results demonstrated that extreme temperatures (hotter summers, colder winters, and greater day-to-day temperature gaps) reduce vulnerability to poverty. This was also supported by the median and average temperatures. Second, there is an association between poverty vulnerability and poverty; that is, poorer people will become poorer with an increase in poverty vulnerability. In fact, in the case of higher income, the higher the probability of returning to poverty, the higher the vulnerability. Policy formulation processes should take into consideration different types of impacts from harsh climate on different vulnerable groups. No single action might be adequate and an integrative approach integrating various strategies and actions are required to overcome challenges posed by climate change and poverty vulnerabilities.

Nationwide Evaluation of Urban Energy System Resilience in China Using a Comprehensive Index Method

The carbon peak and carbon neutrality goals for China signify a critical time of energy transition in which energy resilience is a vital issue. Therefore, a comprehensive evaluation of urban energy system resilience (UESR) is important for establishing a theoretical foundation. To this end, in this paper, 309 Chinese cities were evaluated using a comprehensive UESR assessment framework composed of 113 indices that measured vulnerability and capabilities of resistance and restoration. The results showed that China’s UESR is distributed unevenly and that cities in the eastern region generally have higher resilience than those in other regions. The minimum and maximum UESR results corresponded to Tibet and Shandong, respectively, at the provincial level and Rikaze and Weifang, respectively, at the city level. Regression analysis showed a positive correlation among UESR, carbon dioxide emissions, and GDP.

Building Resilient Cities: Climate Change and Health Interlinkages in the Planning of Public Spaces

Greenhouse gases emissions resulting from the combustion of fossil fuels are worsening air quality and affecting the climate system. While climate change impacts on meteorological variables affects air quality by altering the concentration and distribution of pollutants, air pollution significantly influences the climate, leading to negative impacts on human health. Due to the combination of high temperatures, air pollution, and high population density, cities are particularly vulnerable to climate change impacts. The planning and design of public spaces aimed at climate change mitigation and adaptation can result in multiple co-benefits for human health, while reducing social inequalities. To address the major research gaps in the communication between health and planning experts, and the lack of capacity among public sectors and policy makers, it is necessary to promote capacity building and knowledge sharing between the planning and health sectors. The purpose of this article is to develop preliminary recommendations for a process that allows a comprehensive assessment of the interlinkages between climate and health, social, environmental, and economic vulnerabilities, and the quality of the urban spaces, to support local governments, policymakers, and education institutions in making informed decisions for public spaces. The methods applied were a literature review and interviews with experts.

Urbanization Impact on Regional Climate and Extreme Weather: Current Understanding, Uncertainties, and Future Research Directions

Urban environments lie at the confluence of social, cultural, and economic activities and have unique biophysical characteristics due to continued infrastructure development that generally replaces natural landscapes with built-up structures. The vast majority of studies on urban perturbation of local weather and climate have been centered on the urban heat island (UHI) effect, referring to the higher temperature in cities compared to their natural surroundings. Besides the UHI effect and heat waves, urbanization also impacts atmospheric moisture, wind, boundary layer structure, cloud formation, dispersion of air pollutants, precipitation, and storms. In this review article, we first introduce the datasets and methods used in studying urban areas and their impacts through both observation and modeling and then summarize the scientific insights on the impact of urbanization on various aspects of regional climate and extreme weather based on more than 500 studies. We also highlight the major research gaps and challenges in our understanding of the impacts of urbanization and provide our perspective and recommendations for future research priorities and directions.

Urban Land Expansion from Scratch to Urban Agglomeration in the Federal District of Brazil in the Past 60 Years

Empirical studies of urban expansion have increased rapidly in recent decades worldwide. Previous studies mainly focused on cities in China, the United States or African countries, with Brazilian cities receiving less attention. Moreover, such studies are rare in purpose-built cities. Taking the urban expansion from scratch (1960) to urban agglomeration (2015) in the Federal District of Brazil (FDB) as an example, this study aims to quantify the magnitude, patterns, modes, types and efficiency of urban land expansion and attempts to reveal some implications within sustainable urban expansion thinking. Annual expansion, landscape metrics, local Moran’s I index, area weighted mean expansion index, and land-use efficiency were computed. The suitability of diffusion–coalescence theory and the impact of population growth and urban development policies on urban expansion were discussed. Urban land continuously expanded and became more fragmented during 1960–2015, which mainly occurred in SSW and WSW directions. Urban land evolved in a polycentric way. Edge expansion was identified as the stable contributor, and the importance of infilling and spontaneous growth alternated. Urban expansion in this region supported the diffusion–coalescence theory. Population growth promoted urban expansion, and the creation of peripheral urban nuclei and their development were associated with the urban expansion and the changes in urban land structure. This study adds new empirical evidence of urban expansion to Brazil urbanization, and compact urbanization, population control, and efficient urban land use should be considered in the future.

Two viruses, one prescription: slow down

The COVID-19 pandemic has devastated communities throughout the world. However, the negative impacts of another pandemic, affecting cities worldwide, arguably rival those of COVID. This destructive global health problem, which we have largely ignored, has been described as the “hurry virus” – the culture of speed that dominates modern lives and cities, causing us to constantly strive to ‘go faster’. This hurry virus has comprehensively infected our city transport systems from the early 20^th century. Since then, as speed became a more important goal in city planning than liveability, sustainability and walkability, the consequences for health – human, environmental and economic – have been profoundly damaging. This paper argues that to respond effectively to the hurry virus in city transport, a policy of creating ‘slow cities’ is required. This involves the simultaneous application of two synergistic strategies: slowing the speed of existing motor vehicle traffic; and encouraging greater use of the ‘slower’ active modes. Examples of where such policies have been introduced are discussed. The core of the paper shows how – serendipitously – the world-wide response to the COVID-19 virus in cities has produced policies, strategies and tactics that also provide an antidote to the ‘virus of hurry’. For example, we discuss how cities have rapidly added new or widened bike lanes and sidewalks, and opened streets for people by restricting, slowing or banning motorised traffic. In addition to the intended anti-COVID outcome of providing safer, socially distanced space in neighbourhoods, such policies deliver co-benefits of local healthy living and movement in less-polluted, ‘slower cities’, as well as help combat global heating by reducing CO2 emissions. The paper outlines urban design and operational principles that would promote both pandemic-resistance as well as slower, more local and healthier lives. We show how, in future pandemics, robust plans for rapid, effective action will be required to shut down inter-district connections and implement social distancing to ride out any outbreaks without lasting damage to the city. We discuss one promising strategy that involves relatively self-sufficient and independent precincts, such as 20-minute neighbourhoods that are internally accessible by foot, bike or scooter, that enable people to meet most of their daily needs within an 800 metre (20-minute) return trip from home. If a virus outbreak occurs in one neighbourhood, it can be temporarily closed and isolated from other neighbourhoods, while allowing them to function. The key point is that these responses to combat the COVID virus will produce co-benefits which combat another virus, that of ‘hurry’. The 20-minute COVID-protected city will, by definition, be a hurry-protected, slow city – and what is more – it will be a key component of combatting the overarching existential threat of climate breakdown. We conclude that achieving such co-benefits in cities that remain (or return to being) ‘fast’ would be far more challenging, if indeed possible at all. The pandemics of our time may allow us to reshape the behaviours, values and cultures both of urban residents and policy makers. The paper concludes that we have an unprecedented opportunity to reject the old normal and to re-imagine a new normal of cities that are slower, closer and healthier.

Effects of Albedo and Thermal Inertia on Pavement Surface Temperatures with Convective Boundary Conditions—A CFD Study

The urban heat island (UHI) effect increases the ambient temperatures in cities and alters the energy budget of building materials. Urban surfaces such as pavements and roofs absorb solar heat and re-emit it back into the atmosphere, contributing towards the UHI effect. Over the past few decades, researchers have identified albedo and thermal inertia as two of the most significant thermal properties that influence pavement surface temperatures under a given solar load. However, published data for comparisons of albedo and thermal inertia are currently inadequate. This work focuses on asphalt and concrete as two important materials used in the construction of pavements. Computational fluid dynamics (CFD) analyses are performed on asphalt and concrete pavements with the same dimensions and under the same ambient conditions. Under given conditions, the pavement top surface temperature is evaluated with varying albedo and thermal inertia values. The results show that the asphalt surface temperatures are consistently higher than the concrete surface temperatures. Surface temperatures under solar load reduce with increasing albedo and thermal inertia values for both asphalt and concrete pavements. The CFD results show that increasing the albedo is more effective in reducing pavement surface temperatures than increasing the thermal inertia.

Recent changes in heatwaves and maximum temperatures over a complex terrain in the Himalayas

The temperature response to anthropogenic global warming and forest cover changes is dependent on regional climatic characteristics. It is challenging to segregate the impacts of the two anthropogenic changes on local temperatures and heatwaves over complex mountainous regions. Here we present estimates of regional and local heat stress responses to the recent global climate change and local forest cover loss in complex terrain in the Himalayas using a satellite-based high-resolution land-surface temperature dataset. We find large-scale decreasing trends in the observed frequency of heatwaves and heat days, and localized increases in urbanized and high-elevation regions. Our results show large-scale significant decreasing trends in annual maximum and mean surface temperatures over the period 2003-2019. In locations that have witnessed large-scale forest losses, the declines in the surface temperatures were steeper compared to no-loss regions. We develop a regional multiple linear regression model to estimate the regional and local temperature responses to global climatic change and to segregate them from the response to forest cover losses. Our model estimates a regional decrease of about 2.0 °C in annual maximum temperature over the recent 2003-2019 period, which is locally modulated by the extent of urbanization, forest cover, and elevation. At the locations of intense deforestation, our model successfully predicts a steeper decrease in maximum surface temperature, and estimates the temperature response due to forest loss, after controlling for elevation and initial forest cover. The local cooling effect due to deforestation was reaffirmed by comparing the regions with contrasting forest cover losses. The results suggest that forest clearing amplifies the anthropogenic climate change over the region.

Disentangling the trend in the warming of urban areas into global and local factors

Large cities account for a significant share of national population and wealth, and exert high pressure on local and regional resources, exacerbating socioenvironmental risks. The replacement of natural landscapes with higher heat capacity materials because of urbanization and anthropogenic waste heat are some of the factors contributing to local climate change caused by the urban heat island (UHI) effect. Because of synergistic effects, local climate change can exacerbate the impacts of global warming in cities. Disentangling the contributions to warming in cities from global and local drivers can help to understand their relative importance and guide local adaptation policies. The canopy UHI intensity is commonly approximated by the difference between temperatures within cities and the surrounding areas. We present a complementary approach that applies the concept of common trends to extract the global contributions to observed warming in cities and to obtain a residual warming trend caused by local and regional factors. Once the effects of global drivers are removed, common features appear in cities' temperatures in the eastern part of the United States. Most cities experienced higher warming than that attributable to global climate change, and some shared a period of rapid warming during urban sprawl in the mid-20th century in the United States.

Urban heat island (UHI) intensity and magnitude estimations: A systematic literature review

The severity of urban heat islands (UHIs) is increasing due to global and urban climate change. The damage caused by UHIs is also increasing. To establish a plan to improve the deteriorating thermal environment in cities due to UHIs and to minimize the damage, further research is needed to accurately estimate and analyze the intensity and magnitude of UHIs. This systematic literature review (SLR) is an in-depth review of 51 studies obtained through a five-step filtering process focusing on their analysis of the spatial extent of UHIs, the UHI concept that was used for UHI estimation, and the UHI estimation and analysis methods. This SLR confirmed the need for accurate UHI intensity and magnitude estimation and analysis to reset the existing UHI classification based on the variety of vertical and horizontal ranges where UHIs occur. The results also indicated that the existing UHI energy concepts for estimating UHIs need to be modified and developed to reflect the three-dimensional physical form of the city. Finally, this SLR clarifies the need to develop an optimized analysis method for UHI research. The review results of this SLR will inform future studies and be the cornerstone for establishing policies and plans that can accurately predict and respond to the damage caused by UHIs.

Alternative between Revitalisation of City Centres and the Rising Costs of Extensive Land Use from a Polish Perspective

The phenomenon of spatial chaos is ever-growing challenge in Poland. Its most common explanations are the weaknesses of spatial planning and the households’ economic-based decisions of building a house in the suburbs. In this context, Polish publications lack analyses of the impact of local authorities’ on shaping conditions for the development of new housing and renovation of the existing ones. The authors put forward a thesis about the persistence of an extensive land use policy model in Poland, in which local governments create conditions favouring area-consuming approach to locating buildings. At the same time, the same local governments allow de-agriculturalisation of land plots with a consequence that newly developed areas are not equipped with utilities (e.g., sewage or heating networks). Chaos in the development of residential areas is also illustrated by another phenomenon. Local authorities designate large degraded and revitalisation areas. This results in the dispersed effects. The article concentrates on these three symptoms of spatial chaos in Poland, i.e., random and dispersed expansion of new investments in sewage system, lack of integration between district heating systems and direction of residential development and dispersed effects of revitalisation, which cannot prevent flight from blight. The obtained results allowed to confirm the thesis about the extensive land use policy model in Poland.

Mapping temporal and spatial changes in land use and land surface temperature based on MODIS data

Climate change and the rapid expansion of the built environment have intensified heat stress worldwide. Due to environmental changes and urbanization, some studies show evidence of spatial and temporal changes in heat stress. The objective of this study is to apply spatial analysis to explore temporal and spatial changes in heat stress and to conduct a comparative analysis of land surface temperature (LST) and land use. The results show a significant expansion of the areas where the LST is over 35 °C or between 30 °C and 35 °C. A comparative analysis between the expansion of areas with high LSTs and changing land use types shows that LSTs were indeed higher in 2014 than the values in 2008 and that LSTs remained relatively high in areas where the LST was over 35 °C or between 30 °C and 35 °C. The temperature variation is not significant between urban and rural areas, indicating that heat stress has been extended toward particular rural areas. The cooling effect provided by open space is not significant, so city planners should exert more effort to mitigate extreme heat stress. As a whole, heat stress does change temporally and spatially, and the results of the comparative analysis could be further referenced in future efforts to improve the ability of areas to adapt to heat stress based on various land use patterns.

Untangling Urban Sprawl and Climate Change: A Review of the Literature on Physical Planning and Transportation Drivers

Significant efforts have been dedicated to studying the linkages between urban form, fossil energy consumption, and climate change. The theme of urban sprawl helped to federate a significant portion of such efforts. Yet, the research appears fragmented, at stems from different disciplines and mobilizes different methods to probe different aspects of the issue. This paper seeks to better understand the status of knowledge concerning the linkages between sprawl and climate change through a critical review of the literature published between 1979 and 2018. The exercise entailed revisiting how sprawl has been defined, characterized and measured, and how such parameters have informed the research themes and the approaches mobilized to study its impacts on climate change. For, sprawled environments contribute the climate change directly and indirectly, due to the individual or combined effects of its land use, land cover, urban form, and transportation characteristics. The results indicate that sprawl’s impacts have been mainly investigated in three principal streams of research and based on a limited number of factors or combinations of factors. Though a strong consensus emerges on the negative environmental costs of sprawl, including toward climate change, there remain ambiguities when trying to untangle and weigh specific causes.

Spatiotemporal Dynamics of Net Primary Productivity in China’s Urban Lands during 1982–2015

The rapid urbanization process has threatened the ecological environment. Net primary productivity (NPP) can effectively indicate vegetation growth status in an urban area. In this paper, we evaluated the change in NPP in China and China’s urban lands and assessed the impact of temperature, precipitation, the sunshine duration, and vegetation loss due to urban expansion on NPP in China’s three fast-growing urban agglomerations and their buffer zones (~5–20 km). The results indicated that the NPP in China exhibited an increasing trend. In contrast, the NPP in China’s urban lands showed a decreasing trend. However, after 1997, China’s increasing trend in NPP slowed (from 9.59 Tg C/yr to 8.71 Tg C/yr), while the decreasing trend in NPP in China’s urban lands weakened. Moreover, we found that the NPP in the Beijing–Tianjin–Hebei urban agglomeration (BTHUA), the Yangtze River Delta urban agglomeration (YRDUA), and the Pearl River Delta urban agglomeration (PRDUA) showed a decreasing trend. The NPP in the BTHUA showed an increasing trend in the buffer zones, which was positively affected by temperature and sunshine duration. Additionally, nonsignificant vegetation loss could promote the increase of NPP. In the YRDUA, the increasing temperature was the main factor that promoted the increase of NPP. The effect of temperature on NPP could almost offset the inhibition of vegetation reduction on the increase of NPP as the buffer zone expanded. In PRDUA, sunshine duration and vegetation loss were the main factors decreasing NPP. Our results will support future urban NPP prediction and government policymaking.

Co-benefits and synergies between urban climate change mitigation and adaptation measures: A literature review

Accounting for over 70% of global CO2 emissions, cities are major contributors to climate change. Acknowledging this, urban climate change adaptation and mitigation plans are increasingly developed to make progress toward enhancing climate resilience. While there is consensus that focusing on both adaptation and mitigation is necessary for addressing climate change impacts, better understanding of their interactions is needed to efficiently maximize their potentials. This paper, first, provides a bibliographic analysis to map existing knowledge regarding adaptation-mitigation interactions. This is done using methods such as bibliographic coupling, co-citation analysis, and co-occurrence analysis. Then, drawing on the literature, this study explores two types of interactions between adaptation and mitigation measures, namely co-benefits and synergies. These interactions are explored through analyzing evidence reported in the literature on different measures related to sectors such as energy, transportation, waste, water, green infrastructure, urban planning, and governance. Results of the bibliographic analysis show that there is a lack of research in the Global South. Results of the detailed content analysis show that many measures can provide co-benefits and synergies. Measures related to green infrastructure, buildings, energy systems, and, transportation are particularly capable of providing co-benefits. In addition, it was found that appropriate levels of density, promotion of public transportation, and urban greenery are measures that are more likely to provide synergistic benefits if combined with other adaptation and/or mitigation measures. This study highlights the need for more empirical research to better understand the magnitude of synergistic benefits between different measures.

Analysis of urban heat island characteristics and mitigation strategies for eight arid and semi-arid gulf region cities

The aim of the study is, therefore, to analyze the formation of the UHIs in eight different cities in arid and semi-arid regions. The analysis is based on land cover (LC) classification (urban, green, and bare areas). The study found that bare areas had the highest mean LST values compared to the urban and green areas. The results show that the difference in temperatures between the bare areas and the urban areas ranges between 1 and 2 °C, between the bare areas and green areas ranges between 1 and 7 °C, and between the urban areas and green areas ranges between 1 and 5 °C. Furthermore, the LST values varied for each of the LULC categories, and hence some areas in the three categories had lower or higher LST values than in other categories. Hence, one category may not always have the highest LST value compared to other categories. The outcomes of this study may, therefore, have critical implications for urban planners who seek to mitigate UHI effects in arid and semi-arid urban areas.

Analysing the Driving Forces and Environmental Effects of Urban Expansion by Mapping the Speed and Acceleration of Built-Up Areas in China between 1978 and 2017

Abundant data sets produced from long-term series of high-resolution remote sensing data have made it possible to explore urban issues across different spatiotemporal scales. Based on a 40-year impervious area data set released by Tsinghua University, a method was developed to map the speed and acceleration of urban built-up areas. With the mapping results of the two indices, we characterised the spatiotemporal dynamics of built-up area expansion and captured different types of expansion. Combined with socioeconomic data, we examined the temporal changes and spatial heterogeneity of driving forces with an ordinary least square (OLS) model and a panel data model, as well as exploring the environmental effects of the expansion. Our results reveal that China has experienced drastic urban expansion over the last four decades. Among all cities, megacities and large cities in eastern China, as well as megacities in central and northeast China have experienced the most dramatic urban expansion. A growing number of cities are categorised as thriving, which means that they have both high expansion speed and acceleration. The overall driving force of urban expansion has significantly increased. More specifically, it was associated with population increase in the early stages; however, since 2000, it has been substantially associated with increases in GDP and fixed asset investments. The major driving factors also differ between regions and urban sizes. Urban expansion is identified as being closely associated with environmental deterioration; thus, speed and acceleration should be included as key indicators in exploring the environmental effects of urban expansion. In summary, the results of the presented case study, based on a data set of China, indicate that speed and acceleration are useful in analysing the driving forces of urban expansion and its environmental effects, and may generate more interest in related research.

The Multiple-Scale Nature of Urban Heat Island and Its Footprint on Air Quality in Real Urban Environment

The complex interaction between the Urban Heat Island (UHI), local circulation, and air quality requires new methods of analysis. To this end, this study investigates the multiple scale nature of the UHI and its relationship with flow and pollutant dispersion in urban street canyons with and without the presence of vegetation. Two field experimental campaigns, one in summer and one in winter, were carefully designed in two parallel urban street canyons in the city of Bologna (44°29′ N, 11°20′ E; Italy) characterized by a similar orientation with respect to the impinging background flow but with a different aspect ratio and a different presence of vegetation. In addition to standard meteorological variables, the dataset collected included high-resolution flow data at three levels and concentration data of several pollutants. The UHI has been evaluated by combining surface temperature of building facades and ground surfaces acquired during two intensive thermographic campaigns with air temperature from several stations in order to verify the presence of intra-city neighborhood scale UHIs additional to the more classical urban–rural temperature differences. The presence of trees together with the different morphologies was shown to mitigate the UHI intensity of around 40% by comparing its value in the center of the city free of vegetation and the residential area. To capture the multiple-scale nature of UHI development, a simple relationship for the UHI convergence velocity, used as a surrogate for UHI strength, is proposed and used to establish the relationship with pollutant concentrations. The reliability of the proposed relationship has been verified using a Computational Fluid Dynamics (CFD) approach. The existence of a robust relationship between UHI strength and pollutant concentration may indicate that the positive effect of mitigation solutions in improving urban thermal comfort likely will also positively impact on air pollution. These results may be useful for a quick assessment of the pollutant accumulation potential in urban street canyons.

Longitudinal analyses of the relationship between development density and the COVID-19 morbidity and mortality rates: Early evidence from 1,165 metropolitan counties in the United States

This longitudinal study aims to investigative the impacts of development density on the spread and mortality rates of COVID-19 in metropolitan counties in the United States. Multilevel Linear Modeling (MLM) is employed to model the infection rate and the mortality rate of COVID-19, accounting for the hierarchical (two-level) and longitudinal structure of the data. This study finds that large metropolitan size (measured in terms of population) leads to significantly higher COVID-19 infection rates and higher mortality rates. After controlling for metropolitan size and other confounding variables, county density leads to significantly lower infection rates and lower death rates. These findings recommend that urban planners and health professionals continue to advocate for compact development and continue to oppose urban sprawl for this and many other reasons documented in the literature, including the positive relationship between compact development and fitness and general health.

Longitudinal analyses of the relationship between development density and the COVID-19 morbidity and mortality rates: Early evidence from 1,165 metropolitan counties in the United States

This longitudinal study aims to investigative the impacts of development density on the spread and mortality rates of COVID-19 in metropolitan counties in the United States. Multilevel Linear Modeling (MLM) is employed to model the infection rate and the mortality rate of COVID-19, accounting for the hierarchical (two-level) and longitudinal structure of the data. This study finds that large metropolitan size (measured in terms of population) leads to significantly higher COVID-19 infection rates and higher mortality rates. After controlling for metropolitan size and other confounding variables, county density leads to significantly lower infection rates and lower death rates. These findings recommend that urban planners and health professionals continue to advocate for compact development and continue to oppose urban sprawl for this and many other reasons documented in the literature, including the positive relationship between compact development and fitness and general health.

Face Temperature as an Indicator of Thermal Stress in Outdoor Work Environments

The frequency and duration of heatwaves are steadily increasing as climate change becomes more serious. These changes particularly endanger the health of those who must work outdoors in hot environments. This study introduces a novel approach to monitor the heat-health of airport outdoor workers using infrared thermography. The faces of airport workers who were refueling airplanes in extreme heat conditions were monitored using a thermal infrared thermometer during their work cycle throughout the day. Changes in temperature on their exposed faces (e.g., the ear, cheek, chin) were monitored throughout the day over a two-month period. In every test, the subject’s face temperature increased, then suddenly dropped for a short time, and then continued increasing. Subjects were also asked to assess their thermal perception of the work each time they were tested throughout the study. They reported that they felt discomfort in terms of thermal comfort when the facial skin temperature went down temporarily before the temperature rose. These results show that the physical measurement criteria when outdoor workers’ thermal health is in jeopardy can be based on the results of facial skin temperature measurements.

Effect of Land Use/Cover Changes on Urban Cool Island Phenomenon in Seville, Spain

This paper analyses Seville’s surface urban heat island (SUHI) phenomenon, comparing spatial and temporal patterns of land surface temperature (LST) during July 1987, 2000 and 2017. Landsat data captured throughout three July months were analyzed for the different years, techniques of geographic information systems, ecological variables and geospatial approaches and used to carry out the analysis. The results indicate that from 1987 to 2017, the averaged LST has increased by 9.1 °C in the studied area. The urban areas are colder than their surroundings, suggesting the role of baresoil and cultivated land in the reversal of the SUHI phenomenon. The results show that a fraction of green space has a high unstandardized coefficient (β) through the three time periods. A decreasing trend is also observed in the standardized β “fraction of impervious surface” in the three time periods. The linear regression analysis shows a negative relationship of mean LST with impervious surface fraction due to the presence of shadows projected by buildings, and a positive relationship with green space fraction caused by the influence of baresoil and cultivated land that inverts the LST behavior pattern. The study concludes that there is a need to implement SUHI mitigation strategies during the initial phases of engineering projects where the origin of this problem can be acted upon, since the process of creating streets and public space offers a valuable opportunity to restore the environmental quality and diminish the effects generated by climate change.

On the influence of density and morphology on the Urban Heat Island intensity

The canopy layer urban heat island (UHI) effect, as manifested by elevated near-surface air temperatures in urban areas, exposes urban dwellers to additional heat stress in many cities, specially during heat waves. We simulate the urban climate of various generated cities under the same weather conditions. For mono-centric cities, we propose a linear combination of logarithmic city area and logarithmic gross building volume, which also captures the influence of building density. By studying various city shapes, we generalise and propose a reduced form to estimate UHI intensities based only on the structure of urban sites, as well as their relative distances. We conclude that in addition to the size, the UHI intensity of a city is directly related to the density and an amplifying effect that urban sites have on each other. Our approach can serve as a UHI rule of thumb for the comparison of urban development scenarios.

How UHI intensity responds to variations of urban structure is unclear. Here the authors proposed a reduced form approach that is able to estimate UHI intensities based only on the number and location of urban sites as well as their distance.

Temporal changes in years of life lost associated with heat waves in the Czech Republic

Seniors constitute the population group generally most at risk of mortality due to heat stress. As life expectancy increases and health conditions of elderly people improve over time, vulnerability of the population to heat changes as well. We employed the years-of-life-lost (YLL) approach, considering life expectancy at the time of each death, to investigate how population ageing affects temporal changes in heat-related mortality in the Czech Republic. Using an updated gridded meteorological database, we identified heat waves during 1994-2017, and analysed temporal changes in their impacts on YLL and mortality. The mean impact of a heat-wave day on relative excess mortality and YLL had declined by approximately 2-3% per decade. That decline abated in the current decade, however, and the decreasing trend in mean excess mortality as well as YLL vanished when the short-term mortality displacement effect was considered. Moreover, the cumulative number of excess deaths and YLL during heat waves rose due to increasing frequency and intensity of heat waves during the examined period. The results show that in studies of temporal changes it is important to differentiate between mean effects of heat waves on mortality and the overall death burden associated with heat waves. Analysis of the average ratio of excess YLL/death per heat-wave day indicated that the major heat-vulnerable population group shifted towards older age (70+ years among males and 75+ years among females). Our findings highlight the importance of focusing heat-protection measures especially upon the elderly population, which is most heat-vulnerable and whose numbers are rising.

Which practices co-deliver food security, climate change mitigation and adaptation, and combat land degradation and desertification?

There is a clear need for transformative change in the land management and food production sectors to address the global land challenges of climate change mitigation, climate change adaptation, combatting land degradation and desertification, and delivering food security (referred to hereafter as "land challenges"). We assess the potential for 40 practices to address these land challenges and find that: Nine options deliver medium to large benefits for all four land challenges. A further two options have no global estimates for adaptation, but have medium to large benefits for all other land challenges. Five options have large mitigation potential (>3 Gt CO2 eq/year) without adverse impacts on the other land challenges. Five options have moderate mitigation potential, with no adverse impacts on the other land challenges. Sixteen practices have large adaptation potential (>25 million people benefit), without adverse side effects on other land challenges. Most practices can be applied without competing for available land. However, seven options could result in competition for land. A large number of practices do not require dedicated land, including several land management options, all value chain options, and all risk management options. Four options could greatly increase competition for land if applied at a large scale, though the impact is scale and context specific, highlighting the need for safeguards to ensure that expansion of land for mitigation does not impact natural systems and food security. A number of practices, such as increased food productivity, dietary change and reduced food loss and waste, can reduce demand for land conversion, thereby potentially freeing-up land and creating opportunities for enhanced implementation of other practices, making them important components of portfolios of practices to address the combined land challenges.

Impacts of Urban Form on Thermal Environment Near the Surface Region at Pedestrian Height: A Case Study Based on High-Density Built-Up Areas of Nanjing City in China

The continuous worsening of urban thermal environments poses a severe threat to human health and is among the main problems associated with urban climate change and sustainable development. This issue is particularly severe in high-density built-up areas. Existing studies on the thermal environments (temperature data extracted from satellite remote sensing images) are mainly focused on urban canopy areas (airspace below the average height of trees or buildings) rather than the near surface region (at pedestrian height). However, the main outdoor activity space of urban residents is the area near surface region. Hence, this study aims to investigate the influence of urban form (i.e., building density, height, and openness) on thermal environment near the surface region. The high-density built-up areas of a typical megacity (i.e., Nanjing) in China were selected, and the thermal environments of 26 typical blocks were simulated using ENVI-met software. Temperature field measurements were carried out for simulation validation. On this basis, a classified and comparative study was conducted by selecting the key spatial form elements that affect thermal environments. The results showed that in actual high-density built-up areas, single urban form parameter does not determine the thermal environments near the urban surface but mainly affected by the use (function) of space. For this study, the overall thermal environment of a street block is optimal when the building density is between 40% and 50% and the average building height is between 8 and 17 stories. Nonetheless, the urban form can be improved to optimize the overall effects on building functions and thermal environments. Furthermore, function-specific urban form optimization strategies were proposed to optimize thermal environments according to specific functional needs.

Urban Vegetation in Air Quality Management: A Review and Policy Framework

Recent episodes of high air pollution concentration levels in many Polish cities indicate the urgent need for policy change and for the integration of various aspects of urban development into a common platform for local air quality management. In this article, the focus was placed on the prospects of improving urban air quality through proper design and protection of vegetation systems within local spatial planning strategies. Recent studies regarding the mitigation of air pollution by urban greenery due to deposition and aerodynamic effects were reviewed, with special attention given to the design guidelines resulting from these studies and their applicability in the process of urban planning. The conclusions drawn from the review were used to conduct three case studies: in Gdańsk, Warsaw, and Poznań, Poland. The existing local urban planning regulations for the management of urban greenery were critically evaluated in relation to the findings of the review. The results indicate that the current knowledge regarding the improvement of urban air quality by vegetation is not applied in the process of urban planning to a sufficient degree. Some recommendations for alternative provisions were discussed.

Is Sensible Heat Flux Useful for the Assessment of Thermal Vulnerability in Seoul (Korea)?

Climate change has led to increases in global temperatures, raising concerns regarding the threat of lethal heat waves and deterioration of the thermal environment. In the present study, we adopted two methods for spatial modelling of the thermal environment based on sensible heat and temperature. A vulnerability map reflecting daytime temperature was derived to plot thermal vulnerability based on sensible heat and climate change exposure factors. The correlation (0.73) between spatial distribution of sensible heat vulnerability and mortality rate was significantly greater than that (0.30) between the spatial distribution of temperature vulnerability and mortality rate. These findings indicate that deriving thermally vulnerable areas based on sensible heat are more objective than thermally vulnerable areas based on existing temperatures. Our findings support the notion that the distribution of sensible heat vulnerability at the community level is useful for evaluating the thermal environment in specific neighbourhoods. Thus, our results may aid in establishing spatial planning standards to improve environmental sustainability in a metropolitan community.