Respiratory aerosol particles carrying the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) are a primary cause of the long-distance infection, and insufficient ventilation systems make building occupants highly prone to the coronavirus disease-2019 (COVID-19). As a preventive measure of the aerosolized viable SARS-CoV-2 suspension in building space, we seek to propose an optimal design of the upper-room/drop-ceiling aeration grid system generating vertical laminar airflow (VLAF) as an aerosol barrier. On a test plan (6.1 × 4.7 m) representing the standard hospital patient room in South Korea (a 2.7 m-height room of 77.4 m³ in volume), we investigated the air-terminal size, spacing and air speed that shape uniform downflow of fresh air, minimizing horizontal spread. Our simulation results using the Taguchi method and computational fluid dynamics (CFD) in presence of indoor human expiration indicated that a steady vertical air supply of 0.3 m/s through 0.04m-diameter air diffusers deployed by 0.5 m spacing is the most effective to form VLAF. Physical particle detection tests at the height of 1.5 m in mockup setting of the optimal system design, revealed that expiratory aerosols produced by a single person were almost entirely removable in 20 s. Investigations also confirmed that the proposed design could minimize stagnant airflow regions and would potentially satisfy the indoor air-speed condition for occupant thermal comfort.

The energy consumption of existing buildings depends on their physical features, climatic conditions, and business activities, such as operating hours and occupancy characteristics. It is necessary to perform a fair assessment of building energy performance considering the business activities. It has become especially necessary to collect and manage information on business activities in hospitals since hospitals operate continuously throughout the year, treating patients and using various medical equipment. This study aimed to develop a benchmark that considers business activities and to perform building energy performance assessments in hospitals using the developed benchmark. Initially, the necessary data from hospitals for assessing energy performance and developing an energy benchmark were identified. Then, survey items regarding the business activities and energy consumption of buildings were designed, and a survey was conducted at 48 general hospitals. Secondly, multiple linear regression was used to identify and normalize the major business activities affecting energy use and to develop a benchmark for energy performance assessment. Thereafter, the Energy Efficiency Ratio (EER), the result of comparing the actual energy consumption with the benchmark, was used as an index for the energy performance assessment. Thirdly, additional general hospitals were surveyed to validate the benchmark. The EER of the additional surveyed hospitals was calculated with the developed benchmark. The Energy Use Intensity (EUI) and EER of buildings were reviewed, and analysis was performed to identify why some buildings had a similar EUI but a different EER. Finally, a method to improve the benchmark is presented, and the improved benchmark model is compared with the existing model.

Advanced air mobility (AAM) offers transformative opportunities for urban transportation by potentially alleviating traffic congestion and enhancing mobility. However, implementing AAM in densely populated urban corridors poses significant challenges mainly as a result of noise emissions from its unique vertical takeoff, landing, and low-altitude operations. This study investigates the operational noise challenges of AAM and highlights operational strategies to mitigate noise-related issues. First, the current state-of-the-art in AAM, focusing on noise pollution as a critical concern, was assessed. Second, the potential impacts of AAM operational noise on urban communities were examined. Third, strategies to minimize noise exposure, such as route planning and noise zoning, were developed to ensure regulatory compliance and community acceptance. Furthermore, advanced noise reduction technologies, including optimized vehicle designs and propulsion systems, were explored to reduce noise emissions while maintaining operational performance. The results underscore the importance of adopting adaptive noise reduction technologies and integrating noise management into urban AAM planning. This study provides policy decision-makers and planners with a holistic synthesis view of AAM noise sources, types, and challenges and offers practical strategies for AAM integration. The conclusion yields that addressing noise challenges is essential for AAM’s successful and sustainable integration, leading to quieter, more community-friendly urban airspace. Policy recommendations are made to foster stakeholder collaboration, encourage financial investment in AAM infrastructure, and promote further research into AAM noise reduction and integrative urban planning.

This study investigated the interplay between prior experiences, attitudes and the willingness to reside (WR) in underground spaces, providing insights for improving public acceptance of such environments. This study employed partial least squares structural equation modelling to evaluate the relationships amongst the variables using data from 215 South Korean participants. The findings revealed that prior playing experiences significantly could enhance safety and calmness attitudes and strongly predicting people's WR in underground spaces. Conversely, prior living and working experiences exert minimal influence. While negative effects and confinement attitudes are less impactful, fostering positive emotional experiences is crucial for promoting acceptance. This study has highlighted the importance of designing underground spaces that prioritise leisure activities that cultivate positive perceptions. Additionally, although this research primarily focused on psychological and experiential factors, future investigations are encouraged to explore environmental variables, such as lighting and ventilation, which are critical in shaping public attitudes. These findings offer practical guidance for urban planners and policymakers aiming to develop sustainable and liveable underground environments to address urban density challenges.