High-density Urban Environment Research Articles

A novel method of high-density urban block form generation based on multi-objective solar performance optimization: A case study of Nanjing

Efficiently harnessing solar radiation in high-density urban environments to optimize block forms holds significant potential for advancing urban low-carbon development. This paper introduces a novel method for generating high-density block forms based on comprehensive solar utilization. Grasshopper was used to compile an automated workflow for block form generation, solar simulation, and multi-objective optimization algorithms. Leveraging maximum solar radiation within and surrounding the block and effective photovoltaic utilization ratio are the three objectives in the multi-objective optimization process. From 60,000 generated samples, 1200 block forms were selected as the Pareto fronts. As the plot ratio of the generated blocks increases from 3 to 7, the annual mean solar radiation around the block decreases from 891.3 kWh/m2 to 863.5 kWh/m2, a reduction of only 3.1 %. When the number of blocks within the block increases from 1 to 4, the average solar radiation inside the block increases from 484.8 kWh/m2 to 516.1 kWh/m2, an increase of about 6.5 %. Additionally, as site coverage increased from 30 % to 60 %, the average solar radiation inside the block decreased from 549.2 kWh/m2 to 459.8 kWh/m2, a decrease of approximately 17 %. Notably, the photovoltaic power generation fell from 90.3 kWh/m2 to 61.2 kWh/m2, a decrease of about 32 %. The results indicate that the grid modeling method and multi-objective optimization algorithm adopted in this study can significantly improve the diversity of block morphology and achieve multiple solar performance requirements. The findings support designers in swiftly assessing building volume rationality and solar utilization potential at the early stages of urban design.

Multi-scale correlation analysis between geometric parameters and solar radiation in high density urban environment——Case study in Nanjing

This study explores the impact of multi-scale urban morphology on solar radiation in high-density environments, focusing on Nanjing as a case study. Using Grasshopper, the research decomposed urban models into four scales—district, block group, block, and plot—and analyzed eight morphological indicators, including site coverage (SC), floor area ratio (FAR), and block surface ratio (BSR). Solar radiation was simulated for the entire year, the summer solstice, and the winter solstice. Key findings reveal that different scales exhibit varying influences on solar radiation. At the district scale, BSR shows the highest correlation with annual solar radiation (R2 = 0.96), while at the neighborhood cluster scale, the minimum distance between buildings (DBmin) is most correlated (R2 = 0.7). At the block scale, BSR significantly correlates with summer solar radiation (R2 = 0.55). At the plot scale, no single indicator strongly correlates with solar radiation, but a combination of indicators is more relevant. These findings enable rapid solar performance assessments in urban design, promoting efficient solar energy use.

Effects of Spatial Type and Scale of Small Urban Open Spaces on Perceived Restoration: An Online Survey-Based Experiment

Small urban open spaces are critical components of high-density urban environments, and could bring multiple health benefits. However, the factors related to the restorative effect of these small urban open spaces are not well studied. This study explored how site type (lawn, water, and plaza) and spatial scales (10 × 10 m, 20 × 20 m, 30 × 30 m, and 40 × 40 m) might be associated with small urban open space’s restorative effects. We created the virtual scene images of the 12 sites and used PRS-11 to measure 1130 participants’ perceived restoration when viewing those images. The results indicated that lawn has the highest restorative effects, and are the most preferred. No significant differences in the restorative effects of sites with different spatial scales were detected, even a 10 × 10 m site has considerable restorative effects. We found high preference contributes to larger differences in the restorative effects of lawns and plazas. Those who prefer the sites may gain more restoration increases when viewing lawn scenes compared to plaza scenes. Moreover, adults over 50 years old have higher perceived restorations, and young adults aged 18–25 have a greater increase in restoration between plaza scenes and natural scenes, indicating young adults could benefit more from the building of small green spaces. These findings have direct implications for design practice. More small urban open spaces of lawn and water should be built to provide more restoration benefits, especially for young people.

Integrating vertical farm into low-carbon high-rise building in high-density context: A design case study in Hong Kong

Today's world faces multiple challenges, including climate change, biodiversity loss, and food security. In addition, in the post-pandemic era, there is an urgent need to re-design urban habitats to reduce the epidemic's enduring impacts and reconnect citizens with healthy community activities. As a city with the top population density level in the world, Hong Kong is home to many high-rise communities. This article took the architectural design competition “Green Tower Hong Kong” as an entry point to discuss the technical feasibility and design strategies of integrating high-rise residential buildings with urban agriculture to improve urban food security, enhance on-site solar energy utilization, and develop a sustainable residential environment conducive to low-carbon living and working. The issue of how to improve the dietary structure of Hong Kong residents and reconnect them through space design was focused. Finally, taking the site of Kwun Tong Center as the case study, a resilient residential high-rise building integrated with shared gardens and greenhouses was proposed with a technical-oriented methodology and optimization framework. The final design of mixed-use buildings can provide apartments for 2500 individuals, produce 340,750 kg of vegetables with 156 % self-sufficiency, and generate electricity of 1,080,000 kWh annually. This paper examines strategies for integrating urban agriculture into high-rise residential buildings in high-density urban environments. It proposes a technology-based design optimization method, offering a reference for future explorations of low-carbon, resilient communities.

Designing for health: A study of architecturally oriented models of public space

AbstractIn the post-pandemic period, cities are committed to creating healthier and more healing urban environments. In high-density urban environments, urban complexes are increasingly assuming the function of enriching the external space and activating the vitality of cities, and their architecturally oriented public spaces have great potential for the promotion of residents' health. However, current research on public space and health has focused on green spaces and neighborhoods, and has not yet systematically sorted out the pathways that influence how building-oriented public space can contribute to health. In order to fill the gap, this study attempt to establish a model of health-promoting architecturally oriented public space, which can provide a reference for the similar projects.

Unleashing the potential of urban jogging: Exploring the synergistic relationship of high-density environments and exercise on Residents' Health

This study investigates the influence of high-density urban environments on residents' health, focusing on jogging as a mediating activity. Based on the 5D framework (Density, Diversity, Design, Destination accessibility and Distance to Transit), this study examines GPS trajectory data from 1621 residents in Shanghai, analyses the relationship between high-density urban environments, jogging exercise, and residents' health, using jogging frequency, duration, and distance as mediators, and BMI as a health metric, alongside socio-environmental factors. Key findings include the design of the path environment has a direct positive impact on residents' health. Jogging frequency plays a negative mediating role between Density and residents' health, whereas Jogging distance has a positive masking effect between Density and health, but a negative masking effect between Distance of the path environment and health. Socio-environmental factors indirectly affect health indicators by adjusting the impact of built environment elements on jogging exercise. The Socio-environment has a regulatory effect on the mediating effect of jogging exercise. When the Socio-environment is better, the effects of the Design of the path environment on residents' health through Jogging frequency are more positive, but the effects on residents' health through Jogging distance are more negative. The duration and distance of jogging exercise have a nonlinear effect on health. These research results reveal how high-density urban environments affect residents' health by influencing jogging exercise, providing useful information for future formulation of healthy urban construction strategies.

Identification of Critical Areas of Openness–Vitality Intensity Imbalance in Waterfront Spaces and Prioritization of Interventions: A Case Study of Xiangjiang River in Changsha, China

Identification of Critical Areas of Openness–Vitality Intensity Imbalance in Waterfront Spaces and Prioritization of Interventions: A Case Study of Xiangjiang River in Changsha, China

Integrated assessment of bioaerosol dispersion patterns and infection risk in a typical urban environment: Implications for urban biosecurity management

Exposure to bioaerosols in high-density urban environments will pose a severe threat to human life and health and present significant challenges to the sustainability and resilience of cities. In this study, the aerodynamic dispersion patterns of bioaerosols at two release locations (open and dense areas) under both thermal conditions in Zhongguancun, Beijing, are investigated. By coupling a dose-response model and an improved cellular automaton, the infection risk within exposed populations was assessed, and emergency evacuation strategies for distinct populations in high-risk areas were devised. This study reveals that bioaerosol distribution is notably influenced by factors such as thermal conditions, release locations and pedestrian height. Bioaerosol concentration above the release source decreases with increasing pedestrian height at two release locations. Under the same exposure time, the infection probability of different groups in this area declines with pedestrian height increases, with adult males having the highest and elderly females having the lowest probability. Thermal conditions and building layout near the release source were second only to exposure time in influencing infection probability and evacuation path. Proximity to the release source indicates a high infection probability but a short evacuation distance to safe areas, while downstream areas exhibit lower infection probability but require longer evacuation distances. The layout of buildings near the release source has the most significant effect on evacuation time. Evacuation for high-risk populations should be prioritized upstream or either side of the mainstream. This study aims to mitigate potential biological threats, address challenges in enhancing urban biosecurity management, and enable sustainable urban development.

Optimizing Built Environment in Urban Negative Spaces Using Parametric Methods—Research on a High-Density City in China

In the early stage of architectural design, addressing the challenges posed by negative spaces in high-density urban environments is crucial for enhancing spatial efficiency and building sustainability. Multiple studies employed digital methods and tools to address these issues, such as parametric design, simulation, and genetic algorithms, to investigate architectural generation approaches for urban negative spaces. This article proposes an integrated design process that involves finding the location and form of negative spaces, generating solutions using slime mold and wasp algorithms, and optimizing and analyzing solutions using the Wallacei plugin in Grasshopper. This comprehensive approach underscores the potential of parametric design to yield a multitude of solutions while also acknowledging the convergence challenges encountered during simulations, particularly in optimizing for optimal sunlight exposure during the winter solstice and minimal solar radiation in the summer. Analyzing the optimization goals and parameter values of the 15th Pareto optimal solution in the 100th generation reveals: (1) a higher number of units leads to positive correlation growth in both objectives; (2) within a certain number of units, parametrically generated solutions facilitate the convergence of optimization goals, yielding optimal outcomes. Therefore, factors such as the range of unit quantities and proportions need consideration during early-stage parametric design and simulation. This study explores a design methodology for negative spaces in high-density urban cities, validating the feasibility of various mainstream generation methods and offering insights for future research.

Unveiling the magic of mega-city block environments: investigating the intriguing mechanisms shaping children's spontaneous play preferences.

This study delves into the spatial preferences of children for play spaces within high-density urban block environments, specifically targeting the area of Baihua Second Road in Shenzhen, China. Recognizing the critical role of play in children's development, and the unique challenges posed by dense urban settings, this research employs multiclass logistic regression models and negative binomial regression models to construct a detailed mathematical analysis of neighborhood spatial elements and children's play space preferences. Data was meticulously gathered through both objective observations of 14 different types of spaces within the block, and subjective assessments via children's responses to a series of environment photos, capturing the essence of over 3,000 child participants' interactions and choices. Key findings reveal a pronounced preference among children for soft facility features and visually appealing spatial experiences, suggesting a nuanced understanding of play space needs beyond traditional playground designs. Notably, the study identifies that while cartoon-style designs in play facilities might increase moderate attractiveness, ordinary designs hold broader appeal, indicating a preference for diversity in play space aesthetics. These insights offer profound implications for urban planners and designers, advocating for a child-centered approach in the creation of urban play environments that prioritize aesthetic diversity, and the integration of natural elements. Moreover, the study situates Baihua Second Road as a paradigmatic case, illustrating the methodology and analytical framework applied in addressing the complex interplay between children's play preferences and urban spatial configurations. By incorporating a comprehensive data-driven analysis, this research contributes significantly to the discourse on child-friendly urban design, offering valuable strategies for cultivating inclusive and engaging urban play spaces for children amidst the constraints of high-density city living.

Disaster evacuation challenges in high-density urban neighborhood Kampung Code, Yogyakarta

The article discusses the challenges of disaster evacuation in the high-density urban neighborhood of Kampung Code in Yogyakarta, Indonesia. The rapid urbanization along riverbanks in the area has led to increased vulnerability to flooding and other environmental hazards. The study aims to identify the characteristics and challenges of circulation routes for supporting disaster evacuation in riverbank settlements like the Kampung Code. The research uses a mixed-methods approach, including surveys, interviews, and observations, to gather data using a town-watching approach. The article emphasizes the importance of understanding the specific characteristics of space in these areas to enhance community resilience and disaster recovery. The study occurred in Kampung Jogoyudan, one of the most populated areas along the Code River, and serves as a model for understanding and addressing evacuation challenges in other high-density urban environments.

Exploring the combined cooling effect of street canyon geometry and the surrounding built environment.

Exploring the impact of complex urban morphology on the urban heat island (UHI) effect is essential for sustainable environmental management and enhancing human well-being. This study explored the combined cooling effect of street canyon geometry and the surrounding built environment using a CatBoost model and the Shapley method. The findings indicated that in streets with low building height and density, a high proportion of sky and vegetation and a flatter skyline are conductive to mitigate UHI effect. In streets with high building height and density, a lower proportion of sky and vegetation, and a well-proportioned skyline, can effectively mitigate UHI effect. Regardless of the building density and height around the street, street trees are the optimal choice for greening construction and improvement of large and medium-sized cities in China, given their high controllability and the current urban stock background. Therefore, reasonable control and allocation of street trees can effectively adjust the street canyon geometry, providing suitable cooling strategies for streets with different surrounding built environments. This study proposed a method to mitigate the UHI effect through street canyon geometry, which can be extended to other high-density urban thermal environment studies and guide policymakers on street construction and urban design.

Modeling the long-range transmission of airborne bioaerosol releases in a high-density urban environment

In this study, the effect of different meteorological conditions in four seasons on the flow field in a high-density urban environment was examined using numerical simulations. The effect of different thermal conditions on bioaerosol dispersion was evaluated. The dispersions of bioaerosol under three leakage scenarios, i.e., far from crowds (Release 1), close to crowds (Release 2), and simultaneous leakage at two locations, were analyzed. The flow field analysis shows that the wind speed is higher during the summer solstice than the other dates in the vertical direction. The concentration field analysis shows that compared with stable thermal conditions, the lateral dispersion range of bioaerosol in unstable thermal conditions is smaller and the dispersion distance is longer. Compared to Release 2, the Release 1 condition exhibits narrower lateral dispersion. In simultaneous releases, while the vertical concentration distribution trends remained unchanged, there were notable variations in concentration levels and dispersion range. The deposition analysis shows ground deposition in building areas surpasses building wall surface deposition across diverse leakage scenarios and meteorological conditions. Additionally, in Release 1, unstable thermal conditions enhance bioaerosol deposition on building walls but reduce it on the ground within the building area, compared to stable thermal conditions.

A distributed route network planning method with congestion pricing for drone delivery services in cities

Unmanned aerial vehicle (UAV)-based commercial services, exemplified by drone delivery, have captured wide interest in tech companies, entrepreneurs, and policymakers. Structured route-based UAV operations have been implemented for traffic management of UAVs in support of commercial delivery services in cities. Yet, its essence, multi-path planning with constraints is not well solved in the existing literature. Centralized planning might result in inefficiencies and unfairness in the allocation of precious urban airspace to individual routes. This paper describes a novel distributed route planning method to support UAV operations in a high-density urban environment. The method allows each origin–destination (OD) pair to compete against other OD pairs for an optimized route (e.g. shortest distance), coordinated by a system-level evaluation, leading to a network design that maximizes the performance of not only the individual routes but also the entire system. The core concept is the introduction of congestion pricing, a soft constraint to coordinate the allocation of airspace. The method is tested in standard 2D scenarios and compared with other state-of-the-art methods. The results show that (1) the method is able to generate routes with short individual distances as well as occupying the least airspace by the route network; (2) in some complex scenarios, the method is able to find a solution in a short period of time while other state-of-the-art method fails. The method has also been applied to a real urban environment (Mong Kok in Hong Kong) to demonstrate its capability.

The Mechanism of Street Markets Fostering Supportive Communities in Old Urban Districts: A Case Study of Sham Shui Po, Hong Kong

In old urban districts with tenement buildings, street markets address the working class’s social and economic needs. They are pivotal in fostering supportive communities, in particular for low-income residents in sub-standard housing. However, their outdated overall environment impedes the delivery of adequate support to residents. Prior research on street markets has focused on those in the Americas and Europe, and has revealed the societal support values of these markets. However, studies on street markets in high-density cities like Hong Kong are lacking. This study introduces an evaluation framework to assess the impact of street markets on the development of supportive communities for Hong Kong’s sub-divided apartment residents. Employing the Pei Ho Street market in Sham Shui Po as a case study, an importance-performance analysis highlights critical but underperforming factors including public facilities, activity venues, commerce, and employment. Based on these findings, the study proposes four improvement strategies for the renewal of street markets in high-density communities, which could apply to other cities with similar high-density urban environments. It concludes that street markets in Hong Kong display unique spatial characteristics shaped by low-income lifestyles in a high-density urban environment, enriching daily social life and promoting sustainable community development.

Combining Pocket Parks with Ecological Rainwater Management Techniques in High-Density Urban Environments

In this paper, the benefits of combining pocket parks with Sustainable Drainage Systems (SuDS) in densely built urban areas are demonstrated, through an application proposal in a medium to low-income neighborhood of the historical center of Thessaloniki, Greece. After an outline of the urbanization impact upon rainwater management, the features of the proposed site are presented, in particular those related to rainwater runoff (e.g., rather large ground slope, narrow sidewalks), which result in considerable nuisance, even during medium intensity rainfall events. The choice of the SuDS components, namely a small-scale rain garden and a permeable pavement zone is explained next. Then, the basic design details of the proposed rain garden are given, including the form of the inlet structures and a list of plants, suitable for the climatic conditions of many North Mediterranean regions. The role and the features of the permeable pavement zone are also discussed and some ideas for the urban equipment required to upgrade the park are presented. A preliminary estimate of the cost for the construction of the rainwater management works and for upgrading the available lot to a pocket park is also included. Compared to the cost of sewer pipe network reconstruction, it can be concluded that the proposed solution is cost-efficient, even without considering aesthetic and social benefits. Moreover, it allows for stepwise construction, based on the available funds.

Failed pedestrian street experiments in high-density urban Asia: A matter of policies?

Promoted by sustainable urban agendas and urged by global pandemic measures, street experiments (SE) are booming in Europe but remain latent in Asia. These experiments aim to reconfigure streets as more than spaces for motorized traffic movements, enabling a temporary urban paradigm shift. Such a shift involves balancing active mobility and public space uses in streets while envisioning radically different settings and uses. Recently, eminent scholars urged considering SE in connection to the system and planning framework within which SE are conceived to trace their trajectories. This article examines four decades of temporary-pedestrianization policies and planning instruments in Hong Kong, an Asian city representative of high-density urban environments with highly intensive use of road space and conservative and prescriptive planning. In doing so, the article identifies four trajectories and illustrates two emblematic cases: Chater Road, the first street temporarily pedestrianized under a commercial initiative, and Sai Yeung Choi Street South, a street pedestrianized under a government initiative, now turned back to its original function. The competing roles and practical uses that pedestrianized streets must fulfil partially determined their fate. However, the trajectories these cases followed also differ due to the contextual planning approach and decision-making process. The study contributes to scholarship on SE by shedding new light on the geographical context of high-density urban Asia, forwarding challenges that policymakers might need to address in the planning and governance of SE in similar environments.

Impact of Physical Environmental Factors on Mental Wellbeing of Condominium Dwellers

This paper attempts to reveal the outcomes of the empirical research investigating how the physical environments of the residential high-rises, known as condominiums, including the urban and community contexts, impact mental wellbeing of the dwellers since the emergence of condominiums in Bangkok’s real estate market has continued to proliferate. The principal objectives of the research are to determine the assumption that the high-density urban environment and unique structure of condominiums are the significant determinants affecting occupants’ mental status. Based on the quantitative research approach, the two-stage stratified sampling technique and a cross-sectional survey were performed to engage 1,206 participants from eighteen high-rise condominiums in Bangkok. The interdisciplinary research instruments applied in this study are a Physical-Environmental (PE) Assessment for evaluating the physical environment and surroundings of the condominiums and a Personal and Psychological (PP) Questionnaire for collecting respondents’ attributes and their psychological status quo: safety concerns, privacy satisfaction, and a sense of community at the time of their dwelling in condominiums. At the analytical stage, three inferential statistics, Pearson product-moment correlations, independent sample t-test, and one-way analysis of variance, were applied at the p-value ≤ 0.05. The results endorsed three urban factors: geographical zoning, land use zoning, and density of population as significant dominants of safety concerns, including the sense of community of condominiums’ dwellers, whereas community and architectural factors appeared to have distinctive effects on all three psychological variables.

Modeling walking accessibility to urban parks using Google Maps crowdsourcing database in the high-density urban environments of Hong Kong

Accessing urban parks is important for promoting physical activities and improving public health. In this study, we propose the use of Google Maps crowdsourcing data and the incorporation of park attractiveness to model urban park accessibility in the complex urban environments of Hong Kong. The difference between using geometric and route distance, the effect of park attractiveness in measuring accessibility, and the benefits gained from using walk time compared to distance are investigated. Our result shows that (1) route and geometric distances have a strong correlation with a conversion factor of about 1.5; (2) the common assumption that park size can be a proxy for describing attractiveness may not be correct. Instead, park attractiveness should be explicitly considered for a more effective accessibility modeling; and (3) estimation by walking time shows that there are non-negligible impacts from street conditions and traffic on urban park accessibility. Moreover, district hotspots short of park accessibility or attractiveness can be explicitly detected. Overall, this developed approach provides a flexible and informative approach to model the accessibility to urban parks. The outputs will help city planners, health professionals, and policymakers to evaluate and improve urban park planning and equity in accessibility in high-density cities.

Hong Kong kindergartens in urban space: policy aspirations, historical trajectories, and contemporary disparities

ABSTRACT This paper investigates problems of space in Hong Kong kindergartens. It reports survey findings of a policy study relating to the Kindergarten Education Scheme (KES). KES emphasizes holistic development and child-centred pedagogy, which require larger and more flexible spaces than traditional desk-based learning. The study aimed to explore kindergartens’ responses to the resulting challenges around providing adequate space within Hong Kong’s high density urban environment. Questionnaires were sent to principals of 751 KES kindergartens. 325 valid questionnaires were collected (response rate: 43.5%). Analysis comprised descriptive statistics, inferential tests of relationships between operation mode and other variables, and coding of open-ended question responses. The paper highlights three key findings: (i) kindergartens reported a wide range of challenges relating to space; (ii) most augment their provision by using public spaces outside the premises, but these spaces come with their own challenges; and (iii) there were significant differences in the extent of reported problems between kindergartens operating in different modes, with long-whole-day kindergartens experiencing greater difficulty and disparity. Situating these findings in the historical context of Hong Kong’s uneven urban development, we argue that policy improvement of spatial provision will require reducing pressures on kindergarten spaces, rather than merely setting out spatial standards.