Search Results (44)

The acceleration of industrialization and urbanization worldwide has dramatically improved living standards but has also introduced serious environmental and public health challenges. One of the most critical challenges is air pollution, particularly indoors, where individuals typically spend over 90% of their time. Ensuring good Indoor Air Quality (IAQ) is essential, especially in heavily frequented public spaces such as shopping malls. This study focuses on assessing IAQ in a large shopping mall located in Tabuk, Saudi Arabia, covering retail zones as well as an attached underground parking area. Monitoring is conducted over a continuous two-month period using calibrated instruments placed at representative locations to capture variations in pollutant levels. The investigation targets key contaminants, including carbon monoxide (CO), carbon dioxide (CO₂), fine particulate matter (PM_2.5), total volatile organic compounds (TVOCs), and formaldehyde (HCHO). The data are analyzed and compared against international and national guidelines, including World Health Organization (WHO) standards and Saudi environmental regulations. The results show that concentrations of CO, CO₂, and PM_2.5 in the shopping mall are generally within acceptable limits, with values ranging from approximately 7 to 15 ppm, suggesting that ventilation systems are effective in most areas. However, the study identifies high levels of TVOCs and HCHO, particularly in zones characterized by poor ventilation and high human occupancy. Peak concentrations reach 1.48 mg/m³ for TVOCs and 1.43 mg/m³ for HCHO, exceeding recommended exposure thresholds. These findings emphasize the urgent need for enhancing ventilation designs, prioritizing the use of low-emission materials, and establishing continuous air quality monitoring protocols within commercial buildings. Improving IAQ is not only crucial for protecting public health but also for enhancing occupant comfort, satisfaction, and overall building sustainability. This study offers practical recommendations to policymakers, building managers, and designers striving to create healthier indoor environments in rapidly expanding urban centers. Full article

The rapid development of urban subway network is prompting higher requirements for daylighting in subway stations. The skylight daylighting space of shallow buried subway stations not only improves the quality of light environment but also brings challenges for the optimization of light and thermal performance, especially in areas with hot summers and cold winters. In this paper, key parameters such as illumination, air temperature, and the black sphere temperature of skylight and artificial lighting areas at stations A and B in Shanghai were tested with a field test system. The results show that the light environment in the skylight areas was significantly improved, but the need for regulation and control of the thermal environment increased. Combined with response surface analysis, 10 sample models for two types of daylighting space (partitioned and open atrium styles) were studied and constructed, including 254 simulated working conditions. The results reveal that design parameters such as the number, aspect ratio, depth of light openings, and skylight angle have significant effects on combined energy consumption. The decentralized double slope roof daylighting space has the best performance in partitioned and open atrium-style public areas, and combined energy consumption can be reduced to 385.14 kWh/m². The optimization strategies proposed in this study can provide a quantitative basis for the skylight design of shallow buried subway stations and an important reference for the design of low-carbon and energy-saving underground spaces. Full article

This study investigates how visual environmental factors influence wayfinding behavior in underground spaces, with a particular focus on cultural differences between Korean and Chinese college students. A virtual reality (VR) environment was developed using Unity3D to simulate an underground space, incorporating five key visual variables: passage width, brightness, color temperature (warm vs. cool), the presence or absence of obstacles, and the configuration of sign systems. Participants were divided into two groups—Korean (Group K) and Chinese (Group C)—and engaged in a VR-based wayfinding experiment followed by an emotional vocabulary evaluation. The results indicate significant cultural differences in spatial perception and navigation preferences. Chinese participants preferred narrower, brighter, and cool-colored passages, associating them with an improved sense of direction, lower stress, and enhanced attention. In contrast, Korean participants favored wider, darker, and warm-colored passages, valuing accessibility, stability, and distance perception. Both groups showed a strong preference for environments with floor signage and combined sign systems, though Korean participants were more tolerant of obstacles. These findings provide practical insights for designing more inclusive and navigable underground public spaces across different cultural contexts. Full article

Global navigation satellite systems (GNSSs) exhibit significant performance limitations in signal-deprived environments such as indoor spaces and underground spaces. Although visual SLAM has emerged as a viable solution for ego-motion estimation in GNSS-denied areas, conventional approaches remain constrained by static environment assumptions, resulting in a substantial degradation in accuracy when handling dynamic scenarios. The EMS-SLAM framework combines the geometric constraints and semantics of SLAM to provide a real-time solution for addressing the challenges of robustness and accuracy in dynamic environments. To improve the accuracy of the initial pose, EMS-SLAM employs a feature-matching algorithm based on a graph-cut RANSAC. In addition, a degeneracy-resistant geometric constraint method is proposed, which effectively addresses the degeneracy issues of purely epipolar approaches. Finally, EMS-SLAM combines semantic information with geometric constraints to maintain high accuracy while quickly eliminating dynamic feature points. Experiments were conducted on the public datasets and our collected datasets. The results demonstrate that our method outperformed the current algorithms of SLAM in highly dynamic environments. Full article

Underground pedestrian streets play a crucial role in urban spatial systems, yet the positioning of atrium spaces in existing underground walkways is often determined empirically without adequate consideration of spatial rationality in relation to public environmental behavior. Properly designed atrium spaces can significantly enhance spatial quality and pedestrian experience, effectively revitalizing underground environments. This research investigates the rationality of atrium spatial distribution in underground pedestrian streets, with particular emphasis on developing an evaluation framework for assessing atrium layout appropriateness, using pedestrian congregation patterns shaped by spatial network morphology as the primary evaluation criterion. Through comprehensive field observations and computational simulations, the study examines the interaction between existing underground street network configurations and pedestrian behavior, pioneering the application of spatial design network analysis (sDNA) technology to optimize atrium spatial positioning strategies, thereby establishing a more scientific methodology for atrium layout planning. The proposed approach was validated through a case study of Longhu Underground Pedestrian Street in Handan, ultimately providing a systematic method for verifying atrium distribution rationality. The research establishes an innovative framework that integrates computational analysis into underground spatial planning, incorporates pedestrian flow prediction into architectural design processes, and embeds performance-based evaluation into urban renewal initiatives. Findings demonstrate that sDNA technology can accurately predict pedestrian congregation patterns across various underground street configurations, providing a data-driven foundation for assessing atrium location rationality and supporting the optimization of existing underground spaces. These outcomes are expected to offer valuable scientific references for the design and improvement of atrium spatial distribution in future underground pedestrian systems. Full article

With the acceleration of urbanisation and the increased utilisation of underground space, providing a comfortable and healthy environment in public underground areas has emerged as a significant research topic. This study constructs a comprehensive decision-making framework for underground space environments by integrating human perception evaluations with physical environmental parameters. Using Shanghai Wujiaochang as a case study, field data collection and questionnaire surveys were conducted to evaluate key factors such as temperature (22.63 °C–26.39 °C), wind speed (0.26 m/s–0.67 m/s), and sound levels (59.68 dB–61.21 dB) for commercial-oriented spaces, and 63.15 dB–75.45 dB for transport-oriented spaces) to users’ perceived experiences. The appropriate ranges for key parameters were identified through single-indicator fitted regression analysis and the XGBoost machine-learning model, revealing the relationship between environmental parameters and human perception. The results indicated significant differences in user needs across various functional spaces, with commercial-oriented areas emphasising environmental attractiveness and comfort, while transport-oriented spaces prioritised access efficiency and safety. This study provided quantitative design benchmarks for underground spaces’ dynamic regulation and sustainable management, proposing a precise and adaptive environmental decision-making framework that combines physical parameters with user-perception feedback. Full article

The advancement of ecological civilization has heightened the urgency for urban emission reductions. Currently, there is a significant gap in the quantitative assessment of the carbon neutrality benefit of developing underground space and overlaying urban green land. To address this, this study presents a carbon neutrality benefit assessment model based on building lifecycle theory. The model quantifies the carbon emissions of typical public buildings utilizing aboveground/underground space and assesses the carbon sink impacts of green lands. Notably, it introduces the innovative parameter of characteristic time to evaluate how the comprehensive development of underground space and aboveground urban green land contributes to achieving carbon neutrality. Case analysis of a typical shopping mall in northern China revealed that, in comparison to aboveground buildings, underground buildings exhibit higher energy consumption for construction and lighting; however, they demonstrate superior thermal performance, providing warmth in winter and coolness in summer. Furthermore, urban green spaces of equivalent building area can sequester a portion of the carbon emissions produced by underground buildings, resulting in a lower overall carbon emission profile for the underground space system throughout its lifecycle compared to that of the aboveground space system. Consequently, the development of underground spaces plays a crucial role in advancing carbon neutral objectives. The study also emphasizes the importance of selecting plant communities with enhanced carbon sequestration capacities and developing corresponding green spaces to better meet carbon neutrality objectives. This research offers a novel perspective for evaluating the carbon neutrality benefits of underground space systems, providing valuable design guidance for integrating urban underground and aboveground spaces. Full article

This study examines the impact of changes in temperature and seasonal climate across a 4-year period (2019–2022) and the impact of the existing design on pedestrian activity in the ChiKaHo underground public space in Sapporo, Japan. Using statistical and regression analyses, the study identified boundary temperature ranges for each analyzed point in this space and presented an assumption of the design- and function-related factors influencing the period of use of the ChiKaHo. Each observation point exhibited a unique temperature range of change in pedestrian behavior, from −2 °C (points J1 and J3 near the main transportation station gate and in the corridor, respectively) to +6.8–13.2 °C for points J2 and J4, near open spaces. This research revealed the temperature ranges affecting pedestrian use of underground spaces and that a varying climate has different influences on a particular location. In the future, this can be used as a basis for local design improvements and seasonal adaptation policies to provide a sustainable public underground space in ChiKaHo. Full article

The exploitation of urban subsurface space in urban inventory planning is closely connected to the quality of urban environments. Currently, the construction of underground pedestrian streets is characterised by inefficiency and traffic congestion, making them insufficient for fulfilling the demand for well-designed and human-centred spaces. In the study of spatial quality, traditional evaluation methods, such as satellite remote sensing and street maps, often suffer from low accuracy and slow updating rates, and they frequently overlook human perceptual evaluations. Consequently, there is a pressing need to develop a set of spatial quality evaluation methods incorporating pedestrian perspectives, thereby addressing the neglect of subjective human experiences in spatial quality research. This study first quantifies and clusters the characteristics of underground pedestrian spaces using spatial syntax. It then gathers multidimensional perception data from selected locations and ultimately analyses and predicts the results employing machine learning techniques, specifically Random Forest and XGBoost. The research results indicate variability in pedestrians’ evaluations of spatial quality across different functionally oriented spaces. Key factors influencing these evaluations include Gorgeous, Warm, Good Ventilation, and Flavour indicators. The study proposes a comprehensive and applicable spatial quality evaluation model integrating spatial quantification methods, machine learning algorithms, and multidimensional perception measurements. The development of this model offers valuable scientific guidance for the planning and construction of high-quality urban public spaces. Full article

Underground space has always been used as a resilient solution in addressing the need for safety in terms of climate conditions and defense purposes. This research seeks to recognize the potential of the underground space in the city as a significant urban resilience strategy, with the aim of revealing how contemporary underground architecture is integrated with the public spaces on the surface and how this groundscape integration contributes to the quality of the use of the public spaces to achieve urban resilience. Public spaces have a crucial role in the environmental, social, and sustainable context of the city and are considered urban domains for spatial urban intervention that contribute to urban resilience in its broader understanding. Based on the review of underground space research and the comparative analysis of selected contemporary design projects, the research explores the integration of underground space in correlation with its utilization model based on contemporary design projects. The research results in the systematization of underground utilization among underground infrastructure, underground living settlements, and urban development to offer insights into the enhancement of resilience planning through the contemporary multifunctional usage of underground space. The contribution of this research is reflected in the methodology of developing the criteria for a groundscape resilience concept, in terms of perceiving underground space as an integral urban layer, its multifunctional utilization, and in terms of achieving urban resilience. Full article

The construction of public buildings involves a significant amount of carbon emissions, particularly during the materialization phase of underground construction, which is characterized by a rapid and intense release of carbon emissions. In response to this issue, this study aims to develop a Building Information Modeling (BIM)-based method for assessing the factors influencing carbon emissions during the materialization phase of underground construction in public buildings. To achieve this goal, a process-based quantitative and qualitative method was established to evaluate carbon emissions at various stages, including raw material extraction and processing, building material/equipment production, and on-site processing of components, as well as construction and installation. The proposed method may serve as a valuable tool for selecting design schemes in the early stages of building design. By analyzing 125 actual cases in Xi’an, China and utilizing a carbon emission calculation model, accurate carbon emission data was obtained. This study’s findings indicate a correlation between the embodied carbon emissions and the area of underground space in the cases analyzed. Specifically, larger underground spaces were associated with higher embodied carbon emissions in underground engineering. Furthermore, this study categorized the cases into two groups based on the presence or absence of underground space, resulting in the identification of 16 factors for cases without underground space and 19 factors for cases with underground space. These findings provide valuable insights for understanding and mitigating the impact of carbon emissions during the materialization phase of underground construction in public buildings. Full article

In the past, mill races were part of the urban structure of many towns in Slovakia. As regulated and artificially created waterways, they served to drive mills, rollers, or hammers. With the use of new sources of energy, they lost their functions, and most of them were dried, filled, or buried underground. In our research, we examine the former mill race corridor in Podolínec (Prešov region, Slovakia) and its potential to contribute to urban regeneration strategies. The research steps included the following, namely 1. Identification of the route of the mill race corridor according to historical sources, 2. survey of its current state and its spatial preservation in the urban structure, 3. evaluation of the possibilities of its new uses, which could increase the quality and attractiveness of urban public spaces. The research results show that the fragments of the corridor of the extinct mill race are still identifiable in the urban fabric, and in the cadaster, they are in public ownership and suitable for new uses. The fragments of the corridor of the extinct mill race in Podolínec represent a potential for strengthening the blue and green infrastructure, pedestrian and cycling greenways, and a potential for the presentation of cultural heritage values, which could contribute to the improvement of the qualities of the urban environment. Full article

Landscape occupation and green space reduction have decreased livability and hindered the sustainable development of cities. The urban landscape affects the quality of life and physical and mental state of the public, and urban underground space utilization is important for improving the urban landscape. Therefore, underground space utilization must be explored from a public perspective. Referring to typical underground municipal, transportation, and public space projects, an online questionnaire survey of 377 Nanjing residents was performed to construct a structural equation model investigating their perceptions and preferences regarding underground space usage to improve the landscape, focusing on the links between their preferences and opinions. Underground works that provide diverse open spaces were considered to have the most positive impact on the landscape (82.8%). The aesthetic value of the surface landscape (83.5%) and the vitality of historical sites (82.1%) were the most significantly affected, whereas stock underground space had no significant effect on landscape protection. In terms of age, profession, and place of work, the respondents demonstrated heterogeneous preferences. These findings indicate that targeted publicity and public participation are important to strengthen the cooperative utilization of space and realize the potential of the underground space, helping address actual requirements and develop sustainable cities. Full article

Environmental air pollution poses a significant threat to human health, with nitrogen oxides (NOx) identified as contributors to respiratory and cardiovascular diseases. This study evaluates NOx levels in an underground car park of a hospital complex, where vulnerable patients frequently visit. NOx levels were assessed using direct-reading devices with high-resolution electrochemical sensors measuring NO and NO₂ concentrations. Measurements consistently remained below the legal occupational exposure limit values for car park employees, averaging around 10% of the limit. However, approximately 75% of days recorded NO₂ concentrations exceeding 70% of the World Health Organization’s (WHO) recommendations, with about 20% surpassing the 0.1 ppm limit set by the WHO. The highest recorded one-hour NO₂ level reached 0.165 ppm, typically around 11:00 h. The study recommends that vulnerable patients, especially asthmatics, utilize outdoor parking, while all users should avoid using the car park as a waiting area. Employees are advised to spend more time in enclosed spaces with fresh air. Although occupational levels are generally within limits, environmental levels during peak hours could pose risks to vulnerable populations. Mitigation measures, such as increased ventilation during peak hours and restricted access based on emission levels, are suggested to minimize exposure and protect public health. Full article

With urban development and renewal, underground space is becoming more utilized. The design and use of open underground public space entrances and exits have become more and more frequent. As a pedestrian passage connecting indoors and outdoors, the wind and thermal environment of open entrances have a great impact on human comfort. This paper investigates the open underground space entrances and exits in Xuzhou. Physical environments such as temperature and wind speed were measured. Through numerical simulation, the influence relationships between the spatial form elements of open entrances and exits and microclimate and thermal comfort were investigated. This study showed that there are four common spatial morphological elements of open entrances and exits. The physiologicafl equivalent temperature (PET) of the outdoor part of the entrance is the highest in summer, and the lowest in winter, and the PET is most affected by the shape of the opening plane and the aspect ratio, which are linearly related. The trends of the spatial morphology elements were not consistent when seeking the optimal situation of PET in summer and winter, respectively. The relationship between the spatial form elements of entrances and PET established in this study provides technical guidance for the design of open entrances, which can help improve environmental quality and enhance human comfort. Full article