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Outdoor thermal comfort (OTC) studies explore outdoor subjects' responses to their thermal environment, usually evaluated using the neutral temperature (NT). This study investigated the influences of microenvironmental factors around a waterbody on thermal perceptions, using questionnaires and meteorological measurements at the Central Lake of Southwest University of Science and Technology (SWUST) in Mianyang. Microenvironmental factors included sky view factor (SVF) and distance from the lake (DFL). It was found that people felt most comfortable in the shade of trees although some volunteers voted artificial canopy as their preferred thermal adaptation element. In addition, a linear regression yielded an NT of 28.44 °C in Mianyang during the summer of 2022. There were NT variations among different measurement sites (e.g., on the east shore, it was 28.18 °C on the waterside, 27.11 °C away from the lake, and 25.53 °C far from the lake; while it was 27.57 °C under the tree crown, 25.11 °C on the lawn, and 29.13 °C in the square). This variation may be due to human adaptation towards microenvironmental factors and their effects on microclimate. The variation in thermal responses owing to microenvironmental differences (different NTs at various types of sites) might be a novel finding in the field of OTC. This study provides important directions for microenvironment design in the future for OTC improvement.

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With the increase in population in cities, economic, social, and environmental problems continue to increase, and it is thought that the microclimatic conditions created by these problems will cause more environmental problems. One of the factors affecting the urban climate in urban areas is urban geometry. The climate of a region changes due to the shape of the land surface, human activities, atmospheric movements, and latent and sensible heat fluxes. Sky view factor (SVF), building view factor (BVF), and tree view factor (TVF) are actively used in the determination of urban geometry. However, studies on how these factors affect the thermal state of the urban environment are insufficient. Determining the land surface changes and thermal condition characteristics (LST, NDVI, SHF, and LHF) depending on urban growth and examining how these properties affect thermal conditions are very important in the construction of sustainable urban planning. In the study, SVF, BVF, TVF, LST, NDVI, SHF, and LHF values of 55 points determined for three different areas with different urban geometries were calculated. How these values affect each other and their situation on urban outdoor thermal comfort is evaluated. In the study, statistical analysis was performed to evaluate the relationship between surface temperature, surface heat fluxes, different view factors, and vegetation. As a result of ANOVA analysis, it was determined as very significant (p > 0.01) in all regions. Both SHF and LHF values differ with SVF. The SHF value has a direct relationship with the SVF value. LHF is inversely proportional to the SVF value. The situation is reversed for SHF variation concerning vegetation. LHF and NDVI are directly related. SHF and NDVI are inversely proportional. SVF and NDVI values also vary according to the LST value. It has been observed that LST has a direct relationship with SVF and an inverse relationship with NDVI.

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Global climate change and local urban heat islands enhance urban heat stress. Studies focused at the urban neighborhood scale are limited. Wet-bulb temperature represents the combined effects of both temperature and humidity, and therefore can more accurately reflect human thermal comfort. In this study, air temperature, relative humidity and geographic information of different times, seasons, and sky conditions of the Nanjing Jiangbei New Area were obtained based on mobile measurements. The spatiotemporal variation of wet-bulb temperature at the urban neighborhood scale and the effects of sky conditions, land cover and urban morphology (sky view factor, SVF) were further analyzed. The results showed that: 1) the spatiotemporal variations of wet-bulb temperature at the Nanjing urban neighborhood scale were consistent with that of air temperature. Compared with vapor pressure, air temperature played a dominant role. The extremely high values of wet-bulb temperature in this area were mostly caused by the synergy between air temperature and vapor pressure. 2) The correlation between SVF and wet-bulb temperature was significantly positive in the daytime and negative at night. An increase in the vegetation fraction could reduce wet-bulb temperature, while impervious surfaces had the opposite effect. The wet-bulb temperature significantly decreased and its spatial distribution was much more homogeneous under overcast sky conditions. 3) The horizontal scale effect showed diurnal and seasonal differences and was more sensitive to sky conditions during nighttime than during daytime. Compared with vegetation, the horizontal effect of impervious surfaces was much larger in winter than in the other two seasons. The horizontal scale effects of vege-tation and impervious surfaces on wet-bulb temperature were similar to those of air temperature. These results could provide effective scientific support and a theoretical basis for improving and optimizing the thermal environment of urban neighborhoods, as well as alleviating urban heat stress.

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Urban environments often host a greater abundance and diversity of alien plant species than rural areas. This is frequently linked to higher disturbance and propagule pressure, but could also be related to the additional establishment of species from warmer native ranges in cities, facilitated by the latter's higher air temperatures and drier soils. A hitherto unresolved question is how stressful the urban environments become during climate extremes such as heatwaves and droughts. Do such episodes still favor alien plant species, or set them back? We used in situ measured phenotypic leaf and development trait responses of the six most widespread alien Asteraceae species from various native climates along Belgian urban-to-rural gradients, measured during two unusually warm and dry summers. Urbanization was characterized by three factors: the percentage of artificially sealed surfaces (urbanity, measured at three spatial scales from in situ to satellite-based), the vegetation cover and the sky view factor (SVF, fraction of the hemisphere not blocked by buildings or vegetation). Across species, either from colder or warmer native climates, we found a predominant protective effect of shielded environments that block solar radiation (low SVF) along the entire urban-to-rural gradient. Such environments induced lower leaf anthocyanins and flavonols indices, indicating heat stress mitigation. Shielded environments also increased specific leaf area (SLA), a typical shade response. We found that vegetated areas had a secondary importance, increasing the chlorophyll content and decreasing the flavonols index, but these effects were not consistent across species. Finally, urbanity at the organism spatial scale decreased plant height, while broader-scale urbanity had no significant influence. Our results suggest that sealed surfaces constrain alien Asteraceae during unusually warm and dry summers, while shielded environments protect them, possibly canceling out the lack of light. These findings shed new light on alien plant species success along urban-to-rural gradients in a changing climate.

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Hot weather not only impacts upon human physical comfort and health, but also impacts the way that people access and experience active travel options such as walking and cycling. By evaluating the street thermal environment of a city alongside an assessment of those communities that are the most vulnerable to the effects of heat, we can prioritise areas in which heat mitigation interventions are most needed. In this paper, we propose a new approach for policy makers to determine where to delegate limited resources for heat mitigation with most effective outcomes for the communities. We use eye-level street panorama images and community profiles to provide a bottom-up, human-centred perspective of the city scale assessment, highlighting the situation of urban tree shade provision throughout the streets in comparison with environmental and social-economic status. The approach leverages multiple sources of spatial data including satellite thermal images, Google street view (GSV) images, land use and demographic census data. A deep learning model was developed to automate the classification of streetscape types and percentages at the street- and eye-view level. The methodology is metrics based and scalable which provides a data driven assessment of heat-related vulnerability. The findings of this study first contribute to sustainable development by developing a method to identify geographical areas or neighbourhoods that require heat mitigation; and enforce policies improving tree shade on routes, as a heat adaptation strategy, which will lead to increasing active travel and produce significant health benefits for residents. The approach can be also used to guide post COVID-19 city planning and design.

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We examined the spatial and temporal characteristics of tropical nights (TNs) in Seoul to determine whether land use factors increase the frequency of TN. The number of TN was derived using data from 23 Automatic Weathering Stations (AWS) in Seoul for 1998-2006, and 26 AWS in Seoul and nine Gangnam-gu stations for 2007-2013. The results show that the number of TN recorded in the Seoul Automatic Synoptic Observation System (ASOS) gradually increased from 1971 to 2013. TN occurred most frequently in early August, followed by mid-August, late July, late August, mid-July, early July, early September, and mid-September. The largest annual average difference occurred between Gangnam Station and Yeomgokdong, in spite of the short physical distance (4.5 km) between two stations at Gangnam-gu. There were more TNs at high-rise buildings and commercial business district (CBD) areas with low sky view factors (SVF) than in mountain foothill areas.

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An efficient urban environmental design considers appropriate thermal comfort condition, shaded space, and activity intensity. Physiologically equivalent temperature (PET) and visible sky, i.e., the sky view factor (SVF), are usually used as indicators to determine the outdoor thermal comfort and amount of shaded space, respectively. The activity intensity in urban parks, which is dependent on culture and micrometeorological conditions, was represented inappropriately by attendance density in Taiwan. To optimize the park design and improve the park utilization rate in Taiwan, several environmental factors such as sound pressure levels and numbers of park visitors were measured, and PET values and SVF values were calculated from primary micrometeorological data such as wind speed and globe temperature. This study proposed equivalent continuous sound pressure level (Leq) as a novel indicator to represent park activity intensity and investigated the correlation between Leq and SVF at different PET values. Leq was more appropriate than was attendance density in representing the park activity intensity in Taiwan. In addition, Leq was highly negatively correlated with SVF when visitors felt that the outdoor thermal comfort condition was hot or very hot. In other words, a lower degree of shading in the park resulted in lower activity intensity. Park visitors tended to engage in activities in the shaded regions because of more favorable thermal comfort conditions (i.e., neutral PET). The established quantitative relationships among Leq, PET, and SVF can serve as a reference for park planning.

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Previous studies on thermal comfort in school environments have focused more on indoor thermal environments than outdoor ones, thus providing a limited understanding of occupants' long-term thermal perceptions. Taiwan is located in a subtropical region, where it can be stiflingly hot outside in summer. This highlights the need to ensure proper thermal comfort on campus. In the present study, thermal environment parameters were measured and collected in several outdoor spaces of an elementary school in southern Taiwan. In addition, a questionnaire was used to explore occupants' long-term thermal perceptions of these spaces. During summer months, the physiological equivalent temperature (PET) of these outdoor spaces in over 60% of the daytime in summer between 10 a.m. and 4 p.m. was higher than 38 °C PET, indicating high heat stress. The results of occupants' long-term perceptions of the thermal comfort of these spaces suggested that dissatisfaction with thermal comfort was associated more with solar radiation than with wind speed. Finally, this study simulated a campus environment where more trees are planted and compared the thermal comfort indices before and after the simulation. The results indicated that this solution contributed to a decrease in the PET of these environments, thereby alleviating high heat stress. This study can inform the improvement of microclimates and thermal comfort during campus layout planning. Planting trees judiciously across a campus increases outdoor shades and creates outdoor spaces that are more comfortable and adaptable to hot weather conditions, thereby ensuring frequent use of these spaces.

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Aimed at climate-responsive urban design for tropical areas, the paper attempts to answer the question whether the site-related context affects in some way the perceptual assessment of the microclimate by users of outdoor spaces. Our hypothesis was that visual cues resulting from urban design are important components of the outdoor thermal perception. Monitoring was carried out alongside the administration of standard comfort questionnaires throughout summer periods in 2012-2015 in pedestrian areas of downtown Rio de Janeiro (22° 54 10 S, 43° 12 27 W), Brazil. Campaigns took place at different points, pre-defined in respect of urban geometry attributes. For the measurements, a Davis Vantage Pro2 weather station was employed to which a gray globe thermometer was attached. Two thermal indices were used for assessing the overall meteorological conditions and comfort levels in the outdoor locations: physiological equivalent temperature (PET) and universal thermal climate index (UTCI). Our results suggest that thermal sensation in Rio depends to a large extent on the thermal environment as described by air temperature, PET, or UTCI, and that urban geometry (expressed by the sky-view factor (SVF)) may modify this relationship with increased building density associated to warmer sensation votes under moderate heat stress conditions. This relationship however reverses under strong heat stress with warmer sensations in less obstructed locations, and disappears completely under still higher heat stress, where meteorological conditions, and not the site's SVF, will drive thermal sensation.

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The objective of this research is to assess and analyze the biometeorological perception in complex microenvironments in the Athens University Campus (AUC) using urban micromodels, such as RayMan. The human thermal sensation in such a place was considered of great significance due to the great gathering of student body and staff of the University. The quantification of the biometeorological conditions was succeeded by the estimation of the physiologically equivalent temperature (PET), which is a biometeorological index based on the human energy balance. We carried out, on one hand, field measurements of air temperature, relative humidity, wind speed, and global solar irradiance for different sites (building atrium, open area, and green atrium) of the examined microurban environment in order to calculate PET during January-July 2013. Additionally, on the other hand, PET modeling was performed using different sky-view factors and was compared to a reference site (meteorological station of Laboratory of Climatology and Atmospheric Environment, University of Athens). The global radiation was transferred to the examined sites with the RayMan model, which considers the sky-view factors for the adaptation of the radiation fluxes to simple and complex environments. The results of this study reveal the crucial importance of the existence of trees and green cover in a complex environment, as a factor that could be the solution to the efforts of stake holders in order to mitigate strong heat stress and improve people's living quality in urban areas.

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The purpose of this study was to elucidate the effect of urban morphology representing sky view factor (SVF) on urban microclimate and on human thermal responses. The physical environments and the changes in body temperatures as well as psychological responses were investigated in summer in Bucheon, Korea. The dry bulb temperature ranged from 31.5 °C at SVF 0.082 site to 35.7 °C at SVF 0.922 site. Most of the environmental elements were statistically correlated to the SVF: the dry bulb temperature R (2) = 0.602, UVB R (2) = 0.556 and the illumination level R (2) = 0.609. The mean skin temperature increased up to 36.0 °C at the SVF 0.940 site and decreased to 33.9 °C at the SVF 0.082 site. The mean skin temperature was statistically correlated to the SVF (p = 0.005). However, the core body temperature was not correlated to SVF because of time delay effect to the previously exposed thermal environment. In the investigation of thermal acceptability, only 5 % of subjects were dissatisfied with the road that was covered with plentiful trees; in contrast, approximately 50 % of subjects were dissatisfied with the road with poor solar obstacles in the summer. The thermal stress was affected by the urban morphology, and the plentiful urban greening improved thermal comfort.

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Studies have shown that socioeconomic and environmental factors have direct/indirect influences on TB. This research focuses on TB prevalence of Hong Kong in relation to its compact urban development comprising of high-rise and high-density residential dwellings caused by rapid population growth and limited land resources. It has been postulated that occupants living on higher levels of a building would benefit from better ventilation and direct sunlight and thus less likely to contract infectious respiratory diseases. On the contrary, those on lower floors amid the dense clusters of high-rises are more susceptible to TB infection because of poorer air quality from street-level pollution and lesser exposure to direct sunlight. However, there have not been published studies to support these claims. As TB continues to threaten public health in Hong Kong, this study seeks to understand the effects of housing development on TB occurrences in an urban setting.

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