Urban Density Research Articles

Briefing: Balance – tall buildings, old, new and carbon dioxide: a London perspective

The evolving landscape of tall buildings in London is examined, focusing on their carbon dioxide impact, longevity and adaptability. The challenges faced by ageing skyscrapers like The Gherkin and Tower 42 in maintaining relevance and meeting modern sustainability standards are explored. The importance of balancing embodied carbon dioxide and operational carbon dioxide in building design and construction is also discussed, highlighting recent initiatives in carbon accounting and whole-life carbon assessments. Using case studies of new developments in London's financial district, various approaches to sustainable tall building design are illustrated, including retrofitting existing structures and constructing new, carbon-efficient towers. The conclusion is that tall buildings need to be built with longevity in mind, acknowledging their higher carbon dioxide intensity while recognising their role in meeting urban density requirements.

Scale-specific effects of urban landscape pattern on the COVID-19 epidemic in Hangzhou, China

ContextUnderstanding the scale-specific effects of different landscape variables on the COVID-19 epidemics is critical for developing the precise and effective prevention and control strategies within urban areas.ObjectiveBased on the landscape epidemiology framework, we analyzed the scale-specific effects of urban landscape pattern on COVID-19 epidemics in Hangzhou, China.MethodsWe collected COVID-19 cases in Hangzhou from 2020‒2022 and combined the datasets of land use and land cover (LULC) and social gathering point (SGP) to quantify the urban landscape pattern. Optimal general linear model with stepwise regression was applied to explore the dominant landscape factors driving the COVID-19 transmission in the city. Furthermore, multi-scale geographically weighted regression illustrated the spatial heterogeneity and scale specificity of these landscape variables’ effects to COVID-19 epidemic.ResultsEight landscape variables of LULC and SGP patterns were identified which explained 68.5% of the variance in spatial risk of COVID-19. Different optimal bandwidths across these variables in MGWR indicated their scale-specific effects. LSI of green space enhanced the spatial risk across the entire region. The effects of landscape contagion, the number of water bodies, LSI of cropland and built-up areas, and the density of commercial houses were detected to vary between urban and suburban areas. The effects of LSI of water bodies and the density of shopping malls were found to vary among different districts.ConclusionsIn this study, we firstly discriminated the scale-specific effects of different landscape variables on the COVID-19 epidemic in the urban region. These findings can help to optimize the differentiated zoning prevention and control strategies for COVID-19 in cities and guide policy-making and urban planning at a multi-scale hierarchical perspective to improve public health and urban sustainability.

Addressing Urban Sprawl: is Densification the Solution? A Case Study of Sétif, Algeria

Objectives: The rapid and uncontrolled urban growth in Sétif, northeastern Algeria, has resulted in horizontal densification, continual expansion, and the conversion of agricultural land into urban areas. This transformation highlights the need for effective territorial strategies to manage urban growth sustainably. The primary objective of this study is to promote urban densification through concepts like "inward urbanisation" and "building the city within the city," aiming to optimise land use and counter the negative impacts of urban sprawl. Methods: To address the challenges of urban sprawl and its environmental impacts, the study employs a morphological approach. A Geographic Information System (GIS) is utilised in conjunction with data from the General Census of Population and Housing (RGPH) to analyse spatiotemporal changes in Sétif. This methodological approach enables a detailed examination of the city's morphological and demographic evolution, providing insights into patterns of urban expansion and densification. Results: The findings reveal various strategies for urban development in Sétif, focusing on alternatives to traditional urban density and sprawl. The study identifies and suggests the implementation of new, dense, and hybrid urban forms that align with sustainable development goals. These urban forms are designed to enhance the city’s livability while respecting societal needs and environmental considerations. The strategies proposed address the necessity for adaptable urban designs that support a more compact, resource-efficient city model. Conclusion: This research underscores the importance of rethinking urban planning strategies to manage rapid urbanisation in Sétif. The proposed strategies are essential for transforming Sétif into a dense, sustainable, and appealing urban environment. The study advocates for a shift from expansive urban growth to a densification model that promotes sustainability and aligns with the evolving expectations of the city’s residents.

Greening urban areas in line with population density and ecological zone can reduce premature mortality

Urban green space and urban compactness are each important principles for designing healthy, climate-resilient cities. The principles can co-exist, but greening may come at density’s expense if not considered deliberately. Existing studies estimating health impacts of greening scenarios have not considered what level of greenness is attainable for different population densities. Here, using the square kilometer as the unit of analysis, we estimate non-accidental mortality that could be prevented among adults older than 30 by greening that small area to a level of greenness assumed to be attainable based on its broader urban area (N = 15,917 globally), population density, and ecological zone. Results suggest a large potential for urban greening even in the most population-dense parts of cities such that on average 54 deaths per 100,000 could be prevented per year in those areas. That estimate may be about 25% higher or lower due to uncertainty in the underlying model.

What drives global value chains of FDI at sub-national regions? Roles of agglomeration economies

ABSTRACT This study explores the intricate relationship between Foreign Direct Investment (FDI) and spatial knowledge within the European Union (EU) subnational regions. While existing research has examined this relationship, it often oversimplifies the complexities involved. This study aims to fill this gap by dissecting various types of inward FDI based on sectors, investor origins, and spatial knowledge forms. Using extensive data spanning over 13 years, the study employs negative binomial regression analysis to investigate 223 EU subnational regions. The findings reveal that localized specialization, urbanization, and population density play significant roles in attracting FDI, particularly in manufacturing and logistics. Conversely, capital cities tend to deter manufacturing-related FDI due to resource constraints. Moreover, the study identifies the importance of agglomeration economies, measured by urbanization, in driving FDI across different models given the knowledge spillovers and technological externalities found in densely populated areas. In light of these findings, tailored policies that account for diverse factors – such as regional agglomeration economies and strategic value chain activities – are essential. Recognizing the complexity of multinational business activities is crucial for designing effective policies aimed at reducing regional disparities within the EU.

The Mitigating Effect of Green Space's Spatial and Temporal Patterns on the Urban Heat Island in the Context of Urban Densification: A Case Study of Xi'an

Growing evidence highlights a strong link between urban densification and urban heat island (UHI) effects. However, there is a lack of research on time-based analyses of urban green space spatial patterns using urban densification indices to mitigate UHI effects. Addressing this gap, this study focuses on the central district of Xi'an, utilizing urban density data, MODIS LST products, and Landsat series imagery. The Coordination Coupling Degree Model (CCDM) is applied to longitudinally assess the mitigating effects of urban green space spatial patterns on UHI under different scales of spatial densification. The CCDM results show a significant overall improvement in the coordination coupling degree between green space spatial indices and LST in Xi'an's central district from 2013 to 2023. However, variations across administrative districts suggest that regional planning policies have differentially influenced green space patterns and UHI effects over time. Furthermore, a global negative correlation between the urban densification index and changes in the coordination coupling degree indicates that continued urbanization in Xi'an's central district could exacerbate the urban thermal environment. This study provides valuable insights into green space planning and UHI mitigation strategies in the context of urban densification.

Evaluating the Environmental Kuznets Curve: The Role of Renewable Energy, Economic Growth, Urban Density and Trade Openness on CO2 Emissions. An Analysis for High-Income Countries Using the CS-ARDL Model

Evaluating the Environmental Kuznets Curve: The Role of Renewable Energy, Economic Growth, Urban Density and Trade Openness on CO2 Emissions. An Analysis for High-Income Countries Using the CS-ARDL Model

Spatial suitability of urban land use models for poverty alleviation in the cities of Nigeria

Many models depicting the spatial dimensions of poverty are based on cities in developed countries, raising questions about their appropriateness for urban spaces in developing countries. This study evaluates the spatial suitability of these models in understanding poverty distribution and informing alleviation efforts related to Sustainable Development Goal (SDG). One in cities of developing nations. A grid sampling technique in ArcGIS 10.8 was used to select 1098 households across 56 wards in three mid-sized Nigerian cities. Household data were collected through structured questionnaires using GeoODK, and Maxar high-resolution imagery was used to assess urban building density. The Foster-Greer-Thorbecke (FGT) poverty indices and Pearson correlation were applied for analysis. Results showed that over 29 wards had a poverty incidence and gap index greater than 0.20, while poverty severity remained below 0.20 in most wards. High building density was more prevalent in the city’s interior. Significant correlations were found between the income poverty gap (p = 0.005, r = 0.367), poverty severity (p = 0.009, r = 0.346), and building density. The study concludes that these models are suitable for informing poverty alleviation policies in mid-sized cities of developing countries, especially Nigeria.

Revealing the transformation of spatial structure of greater Cairo: Insights from satellite imagery and geospatial metrics

Greater Cairo (GC) is the seventh-largest metropolitan city globally. In recent decades, GC has witnessed massive urban expansion, which has yet to be empirically measured or characterized. This research seeks to explore the patterns of urban growth and changes in urban form in GC from 1973 to 2021 using remote sensing and geospatial metrics. Six Landsat images in 1973, 1984, 1992, 2003, 2013, and 2021 were used to explore urban growth in GC. Urban Land Density Function (ULDF), Landscape Expansion Index (LEI), and Fractal Dimension Index (FDI), were utilized to analyze various aspects of urban expansion. Additionally, the ratio of Land Consumption Rate (LCR) to Population Growth Rate (PGR) was calculated to assess the correlation between urban expansion and population changes. Our results reveal a substantial addition of 203 thousand hectares of urban areas over the last half-century. The ULDF highlights GC’s transformation from a condensed to a scattered urban landscape, particularly with the establishment of the New Administrative Capital in the vicinity. Edge expansion emerged as the principal type of urban growth throughout the research duration. The consistent increase in FDI from 1.44 in 1973 to 1.75 in 2021 signifies the fragmentation of the urban landscape. Moreover, the progressive rise in LCR from 0.023 in 1984 to 0.050 ​ha per person in 2021 suggests a steady expansion of low-density urban areas. Notably, the LCR-to-PGR ratio escalated from 0.878 in 1984 to 2.428 in 2021, indicating that urban expansion surpassed population growth. These results will help further understand the characteristics of GC’s urban expansion and may offer a scientific foundation for policymakers to reconsider the current horizontal expansion policy in GC.

Preliminary Assessment of Morphology and Elemental Composition of Fine Particulates in Selected Urban Areas of Java Island

Rapid urbanization and high population density in three major cities in Indonesia, Bandung, Jakarta, and Tangerang have led to significant air quality issues. Fine inhalable particles (PM2.5) with distinct morphologies and elemental compositions pose considerable health risks. This study evaluates the morphology and chemical composition of PM2.5 in these urban areas on Java Island. PM2.5 samples were collected for 24-hour periods using a Teflon filter with the Super Speciation-Air Sampling System (SuperSASS) following the EPA sampling schedule, from May to September 2022. The Teflon sample with the highest PM2.5 concentration, representative of both weekdays and weekends, was selected for morphological analysis using Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and elemental characterization using Energy-Dispersive X-ray Fluorescence (ED-XRF) Epsilon. SEM images revealed distinct morphological characteristics at each site. In Bandung, particles were irregularly shaped, agglomerated, and flaky, with sizes ranging from 1.1-1.6 µm on weekdays and 0.9-1.3 µm on weekends. Jakarta has particles with semi-crystalline, tabular, elongated, and puff-like morphology, with sizes predominantly from 0.5-0.8 µm on weekdays and 0.9-1.3 µm weekends. In Tangerang, particles were irregularly faceted and agglomerated, with sizes between 0.5-1.3 µm on weekdays and 0.9-1.4 µm on weekends. Teflon-derived minerals (C,F) were present across all sites. EDX spectra revealed Ca-rich particles in Bandung, while S-rich particles were observed in Jakarta and Tangerang. XRF analysis further proved the major and minor elements, reflecting local pollution sources. The combined use of SEM-EDX and XRF offers a comprehensive profile of PM2.5, highlighting specific pollution sources in each city.

‘They’re not dog friendly because they’re not anyone friendly’: living with dogs in two densifying London neighbourhoods

Since the late 1990s, policy makers in the UK have promoted building higher density housing. Notably absent from this policy are the companion animals with whom we share our homes and public spaces. Their absence is all the more surprising given that dog companionship is often associated with the same outcomes as championed by the density and compact city agendas—social cohesion, community well-being, and active lifestyles. Based on research conducted in two London neighbourhoods, this paper explores how people experience urban density when with a dog, the challenges and opportunities they encounter, and how they negotiate their way through an often confusing and unspoken web of rules, laws and norms. The research builds on work which examines human-dog relations, arguing that the lack of clarity around where dogs are and are not welcome is reflective of the ways dogs are ambiguously positioned in relation to discourses of density and urban living. The ways urbanism is promoted in the UK is not politically neutral, nor are the ways some dogs are included or excluded from this imagining. We argue that the absence of clarity about dogs is constitutive of shifting and often confusing discourses about animals, urbanism, and densification.

Deciphering the Covid-19 Density Puzzle: A Meta-analysis Approach

The COVID-19 pandemic has sparked widespread efforts to mitigate its transmission, raising questions about the role of urban density in the spread of the virus. Understanding how city density affects the severity of communicable diseases like COVID-19 is crucial for designing sustainable, pandemic-resilient cities. However, recent studies on this issue have yielded inconsistent and conflicting results. This study addresses this gap by employing a comprehensive meta-analytic approach, synthesizing data across diverse regions and urban contexts to offer a broader, more nuanced perspective on the impact of city density. A systematic meta-analysis was conducted, initially screening 2,452 studies from Google Scholar, Scopus, and Avery Index databases (up to August 31, 2023), and narrowing down to 63 eligible studies. Using the restricted maximum likelihood (REML) method with a random effects model, the study accounted for variations across different studies. Statistical tests, file drawer analysis, and influence measure analysis were performed, along with assessments of heterogeneity and publication bias through forest and funnel plots. Despite this extensive analysis, the findings indicate that city density has a negligible effect on the severity of COVID-19, challenging the prevailing assumptions in the literature.

URBAN HEAT ISLAND ANALYSIS USING GIS AND REMOTE SENSING IN KOSHOFE LAGOS STATE

Urban heat islands (UHIs) are a significant concern in urban areas, particularly in tropical regions like Lagos, Nigeria. This study employs geographic information systems (GIS) and remote sensing (rs) techniques to analyze the urban heat island effect in Koshofe, a rapidly urbanizing area in Lagos. The research aims to identify the spatial distribution, intensity, and factors influencing UHI in koshofe. Using Landsat 8 and sentinel-2 satellite imagery, land surface temperature (LST) was retrieved and analyzed. GIS spatial analysis and mapping techniques were applied to examine the relationship between lst, land use/land cover (LULC), population density, and urban morphology. The study also investigated the impact of urban planning strategies on UHI mitigation. Results show that Koshofe experiences significant UHI effects, with lst varying between 28°c and 38°c. Built-up areas, particularly commercial and industrial zones, exhibited higher (LST) values compared to vegetated areas. Population density and urban density were found to be positively correlated with (LST). The study identified areas with high UHI risk, including major road networks and informal settlements.

Urban Renovation from Precarious to Sustainable Districts: Study Case of Mvog-Ada in Yaounde

This article explores the possibility of transforming precarious neighbourhoods, commonly known as slums, into good-living and environmentally- friendly places by rethinking their layout. It examines the state of the study case and highlights the relationships between the road system, parcels of land and other components of the urban fabric, with the aim of resolving the problems caused by the poor occupation of urban space and the lack of architectural knowledges and basic infrastructure necessary for people's lives in Cameroon. This research addresses the problems of anarchic urbanisation, urban densification and unhealthy living conditions, it proposes concrete solutions for decongesting the area, strategically redeveloping the space and ensuring the sustainable development of the site, while incorporating a biomimetic and circular approach. To achieve this goal, it was important to put in place a renovation strategy that is both up-to-date and adapted to the local context. With this in mind, this work presents a comprehensive and innovative master plan designed to solve the problems of development, bad urban traffic and degradation of the area through the use of an appropriate methodology of sustainable urban planning. Finally, the concept of sustainable district is presented as a pillar of the development of precarious districts and as an opportunity of growth for the development of their country.

INTEGRATING SOCIO-ECOLOGICAL CONNECTIONS INTO URBAN PLANNING

Urban ecology increasingly recognizes urban vacant lots as spaces with untapped aesthetic, social, and environmental potentials. This study focuses on strategies for converting these lots into green areas in Mossoró, a semi-arid city in Brazil, by analyzing urban connectivity patterns. Using a Geographic Information System, the study identifies priority areas for green space conversion based on factors like urban planning, density, land cover, and vacant lots. The analysis revealed 429 hectares of highly suitable land for conversion. A resistance surface was also created, factoring in public amenities and urban infrastructure, which showed varying levels of resistance to human movement. Areas with well-developed infrastructure had lower resistance, encouraging human and ecological movement. Connectivity modeling highlighted a need for more green infrastructure, especially in peripheral regions, to address socio-spatial fragmentation and enhance urban resilience in Mossoró. Keywords: Connectivity, Green Infrastructure, Urban Vacant Lots.

Distribution Patterns of Urban Spontaneous Vegetation Diversity and Their Response to Habitat Heterogeneity: A Case Study of Five Cities in Heilongjiang Province, China.

Spontaneous vegetation is an important component of urban biodiversity and an excellent agent for exploring the mutual feedback mechanism between urbanization and urban ecosystems. Rapid urbanization has had a significant impact on the composition, structure, and distribution patterns of urban spontaneous vegetation diversity. Studying the diversity distribution patterns and causes of urban plant communities is beneficial for understanding the formation and maintenance mechanisms of plant diversity in specific urban habitats. This study selected five cities in different climate subregions of Heilongjiang Province as research targets and conducted field research using uniform sampling and typical sampling methods. The composition, distribution pattern, and driving factors of spontaneous vegetation were analyzed. The results showed the following: (1) A total of 633 examples of spontaneous vegetation were recorded, belonging to 93 families and 341 genera, mainly consisting of herbaceous plants and native plants. (2) The diversity index and similarity index of spontaneous vegetation in gravel-type abandoned land habitats are higher than those in other habitat types, while the diversity index of spontaneous vegetation in trees and shrubs is lower, and there is no significant difference in regards to different habitats. (3) Urban population density is a key factor affecting the diversity of native plants, while woody plant coverage, patch area, and landscape trait index are key factors affecting non-native plants. (4) The results of canonical correspondence analysis (CCA) showed that the total explanatory power of environmental characteristic factors in regards to the distribution pattern of spontaneous vegetation was 7.5%. The closest distance between adjacent patches, the coverage of woody plants in patches, the distance from the city edge, the patch area, and the surface impermeability of the buffer zones were key factors affecting the distribution of dominant species in spontaneous vegetation communities. The research results will provide an important reference for the conservation of urban biodiversity and the construction of low-maintenance urban green space plant landscapes in Heilongjiang Province.

From urban clusters to megaregions: mapping Australia’s evolving urban regions

This study employs percolation theory to investigate the hierarchical organisation of Australian urban centres through the connectivity of their road networks. The analysis demonstrates how discrete urban clusters have developed into integrated regional entities, delineating the pivotal distance thresholds that regulate these urban transitions. The study reveals the interconnections between disparate urban clusters, shaped by their functional differentiation and historical development. Furthermore, the study identifies a dichotomy of urban agglomeration forces and a persistent spatial disconnection between Australia’s wider urban landscape. This highlights the interplay between urban densification and peripheral growth. It suggests the need for new thinking on potential integrated governance structures that bridge urban development with broader social and economic policies across regional and national scales. Additionally, the study emphasises the growing importance of national coordination in Australian urban development planning to ensure regional consistency, equity, and productivity.

Potential for Utilizing Organic Waste as a Heat-Insulating Composite

The ever-increasing global population growth has a direct impact on residential building demand, which often does not keep pace with construction growth. This condition leads to an increase in housing density and a decrease in construction quality, which contributes to excessive heat inside homes. Therefore, this research explores the use of organic waste, specifically reeds and young coconut fiber, as environmentally friendly thermal materials to reduce dependence on artificial energy and its negative impacts. The high cellulose content in reeds and the fiber in young coconut fiber is a combination that has the potential to create an effective heat absorber. Product composition material testing was carried out using a thermogun, and the results were analyzed using the one-way Analysis of Variance (ANOVA) method. This research aims to utilize the potential of organic waste to produce insulation that can reduce heat temperatures in buildings, with the hope of finding alternative materials that are more sustainable and environmentally friendly.

Examining the Causal and Heterogeneous Influence of Three-Dimensional Urban Forms on CO2 Emissions in 285 Chinese Cities

Despite the efforts to examine the influence of urban forms on CO2 emissions, most studies have mainly measured urban forms from a two-dimensional perspective, with relatively little attention given to three-dimensional urban forms and their causal relationships. Utilizing the built-up area dataset from the Global Human Settlement Layer (GHSL) project and the carbon emission dataset from the China City Greenhouse Gas Working Group (CCG), we examine a causal and heterogeneous effect of three-dimensional urban forms on CO2 emissions—specifically urban height, density, and intensity—in 285 Chinese cities. The empirical results reveal a robust and positive causal effect of 3D urban forms on carbon emissions. Even when incorporating the spatial spillover effect, the positive effect of 3D urban forms remains. Moreover, GDP per capita and total population have a greater impact on urban CO2 emissions. Additionally, we find that the influence of 3D urban forms on CO2 emissions is U-shaped, with total population serving as a moderating factor in this effect. Importantly, there is significant geographic and sectoral heterogeneity in the influence of 3D urban forms on CO2 emissions. Specifically, the influence of 3D urban forms is greater in eastern cities than in non-eastern cities. Furthermore, 3D urban forms primarily influence household carbon emissions rather than industrial and transportation carbon emissions. Therefore, in response to the growing challenges of global climate change and environmental issues, urban governments should adopt various strategies to develop more rational three-dimensional urban forms to reduce CO2 emissions.

Examining the relationship between the built environment and carbon emissions from operating vehicles: enlightenment from nonlinear models.

Carbon emissions from urban transportation significantly contribute to overall transportation emissions and are a major cause of the continuous rise in global temperatures. Understanding the spatial distribution and influencing factors of carbon emissions from operating vehicles can aid in formulating targeted policies and promoting emission reduction. To analyze the factors influencing urban traffic carbon emissions, we calculated emissions using trajectory data from operating vehicles in Shenzhen. We then used gradient boosting regression tree methods, specifically RF, XGBoost, and LightGBM models, to analyze the impact of the built environment on vehicle emissions. We used the XGBoost model for detailed factor analysis by comparing the models. The results indicate that bus stops, intersections, housing density, metro stops, and land use mix are the top five factors influencing emissions. When road density is 0-15 km/km2, the distance from the city center is 0-6 km, and the population exceeds 2000/km2, the built environment significantly reduces vehicle emissions.