Planting trees is an effective way to regulate the outdoor thermal environment and combat urban heat islands (UHIs). Tree species and layout can have a considerable effect on, for example, the outdoor shading and wind fields, and finally the distribution of the occupant thermal sensations in outdoor spaces. We studied the influence of common tree species and layouts on the outdoor thermal environment under typical summer and winter weather conditions in the hot–humid areas of China. Each arbor model was established by the physical parameters obtained from field measurements. Physiological equivalent temperature (PET) was used to evaluate the thermal performance of the outdoor environment. The ENVI-met software was validated with field measurements and then used to assess the outdoor thermal environment under typical summer and winter weather conditions. The results showed the following: (1) Without considering the tree species, the difference in maximum PET values for different planting distances in summer and winter was 1.14 and 2.13 °C, respectively. (2) Planting arbors with different planting methods in inactive spaces had little effect on the thermal environment of the surrounding active space. (3) Arbors with high leaf area density (LAD) values performed better in regulating outdoor thermal comfort than arbors with low LAD values. The maximum differences in PET values of different arbors in summer and winter were 0.98 and 1.37 °C, respectively. This study provides practical suggestions for arbor planting in square spaces in the hot–humid areas of China.

Hot and humid areas experience constant high temperatures and high humidity during summer, causing widespread concern about outdoor thermal discomfort. This paper investigates the effects of landscape design strategies on outdoor thermal environments during typical summer and winter weather conditions in the hot–humid areas of China. The physiological equivalent temperature (PET) is used for evaluating the thermal performance of the proposed outdoor environments. ENVI-met software was validated via field measurements for this study and was used to evaluate the outdoor thermal environment under typical summer and winter weather conditions. Three kinds of common landscape elements were analyzed: tree species, pavement, and water bodies. The results show that (1) by properly arranging landscape elements, the PET can be reduced by up to 1.6 °C in summer without sacrificing relevant thermal comfort during winter. (2) Arbors with high leaf area density (LAD) values performed better than those with a low LAD value for improved outdoor thermal comfort. (3) The influence of pavement on outdoor thermal comfort differs when under conditions with and without shade. This study provides practical suggestions for landscape design in open spaces within hot–humid areas.

The downtown cores of many cities are characterized by aged communities that tend to host a relatively high population of elderly retirement residents. The availability and usage of outdoor spaces within these communities play a crucial role in promoting active aging, providing essential locations for rest, activities, and social interaction among the elderly. However, in the planning and design of these spaces, attention is often focused on the safety and mobility requirements of the elderly population, while a lack of research is apparent in the area of elderly-specific preferences for spaces designed for relaxation and communication. In this study, we selected an aging community as the research target and conducted a detailed investigation of the outdoor spaces where the elderly residents gather and build up spontaneously in summer. Our objective was to evaluate the environmental factors influencing the selection of these outdoor spaces by the elderly for relaxation and communication. We analyzed the correlations between these factors and the number of occupants in these spaces and developed predictive models accordingly. The findings indicate that the environmental factors impacting the utilization of outdoor spaces by the elderly during heat periods within the community are, in order of importance: temperature, relative humidity, human traffic flow, and noise levels. These factors include physical and social aspects; temperature is a negative correlation factor affecting the use of outdoor space by the elderly, and the rest are positive correlation factors. This shows that the elderly like to gather and chat in a cool, crowded, and lively environment. Through the data analysis, it was determined that the random forest regression model was the most effective in predicting the number of residents remaining in these spaces. With a coefficient of determination (R²) of 0.7958, the model can assist in community update planning and design, help in selecting outdoor spaces, and improve the quality of the outdoor environment. This study discusses the factors influencing the elderly’s use of community outdoor space from the physical and social levels, and the prediction model is significant for the optimization of spatial elements and spatial location.

The skylight on the roof of an atrium can be popular for commercial malls to illuminate the core area of the building. However, the solar radiation and its heat can get into the building together with the daylight, causing excessive cooling load. This paper studies the daylighting and energy performances of skylight coverage area for the air-conditioned atriums in the hot and humid regions. The energy performance with different atrium heights, glass types and the coverage ratios of the skylight are studied. The daylight performance was simulated by the ray-tracing Radiance and was transferred into EnergyPlus for energy evaluations. The finding suggested that, for hot and humid climates, the skylight coverage ratio should be controlled carefully to prevent the excessive solar heat gain. When the on/off lighting control is applied, the total energy consumption of the single-floor cases (or of the top floor for the multi-floor cases) leveled off when the coverage ratio of the skylight reached 9%. Thus, the skylight is favorable to the energy saving of the low-rise or single-floor commercial buildings only under the current assumptions, as the ground of the atrium cannot be well illuminated while the excessive solar radiation gets into the building. The skylight should be shaded in cooling seasons to prevent the excessive solar heat gains.

Due to global temperature increases, terraced house (TH) residents face a threat to their health due to poor indoor thermal environments. As buildings are constructed by low-income residents without professional guidance, this study aims to investigate the indoor thermal comfort and energy resilience of THs under the future climate and determine the optimal passive design strategies for construction and retrofitting. By exploring the effects of building envelope structures, adjusting the window-to-wall ratio (WWR) and designing shading devices, EnergyPlus version 22.0 was used to optimize the thermal environment and cooling load of THs throughout their life cycle under future climate uncertainties. Unimproved THs will experience overheating for nearly 90% of the hours in a year and the cooling load will exceed 60,000 kWh by 2100 under the Representative Concentration Pathways (RCP) 8.5 scenario. In contrast, optimization and improvements resulted in a 17.3% reduction in indoor cooling load by increasing shading devices and the WWR, and using building envelope structures with moderate thermal insulation. This study can guide TH design and renovation, significantly reducing indoor cooling load and enabling residents to better use active cooling to combat future overheating environments.

The proportionality between urban building expansion and population growth is a key indicator of sustainable development, yet its global patterns and drivers remain underexplored. This study investigates the discrepancies between building volume and population growth rates (ΔR) across 1,744 cities in 12 major global economies from 2000 to 2020 using satellite-based building volume and population databases. Results reveal significant regional disparities: cities in East and Southeast Asia tend to construct buildings at rates exceeding population growth, while many cities in Europe and North America show conservative building developments with ΔR close to or lower than zero. Socioeconomic factors such as gross domestic product (GDP), population size, and spatial clustering around the regional economic centers further explain these patterns, particularly in economies of the Global South. These findings emphasize the need for region-specific approaches and strategies to achieve sustainable urban development.