Pedestrians' behavior based on outdoor thermal comfort and micro-scale thermal environments, Austin, TX

Assessing thermo-physiological effects of different tree species within the inner regions of the urban canyon; confronting in-situ extreme heat stress in Istanbul during the El-Niño summer of 2023

This study investigates the impact of street morphology and tree species on thermal comfort in Istanbul during the July 2023 El Niño event, focusing on worst-case scenarios. Field measurements were conducted in the most common street morphologies and compared with data obtained from meteorological stations (MS). Subsequently, the influence of tree presence were evaluated for the measured streets, and PET assessments were conducted by incorporating fisheye photographs of the most common tree species in the region into the SVF calculations. The results indicate that EW-oriented streets, particularly the Left Lateral, experience beyond extreme heat stress due to extended sun exposure. PET results from MS were inconsistent with local conditions. The analysis of Platanus orientalis, Populus canadensis, and Robinia pseudoacacia on PET in different street orientations showed reductions of 5-6 °C, particularly for the first two species during morning and midday. This equates to a PET reduction from Beyond extreme heat stress (I) to Extreme heat stress, for heat stress beyond 41 °C. Although this reduction is significant, tree shade had limited impact under such extreme heat. The study found that trees on the left side were more effective when placed on one side, while the right side provided stronger cooling when trees were on both sides in both E-W and N-S streets. Additionally, during the El Niño period, the influence of street morphology on thermal comfort in 'Csa' climates begins to reflect the conditions of 'BWh' climates, with higher levels of heat stress. As climate change continues to intensify, these extreme heat conditions may become typical in the future.

Influence of view factors on outdoor thermal comfort of residential areas in hot-humid regions

Sky View Factor (SVF) is commonly used to describe the impact of urban geometry on the urban thermal environment. Shading effects from plants and buildings also exert a considerable influence. To investigate the influence of view factors on outdoor thermal comfort in residential areas, we employed the Physiological Equivalent Temperature (PET) and view factors (SVF, TVF, BVF) as indicators to determine outdoor thermal comfort and the quantity of shaded spaces. Thermal measurements collected from 13 points in Guangzhou, China, Our findings revealed that high TVF points exhibited more stable air temperature throughout the daytime, with average temperature differentials ranging 0.4-1.9 °C lower than other points. Air temperature demonstrated a positive correlation with SVF (R2 = 0.53), while exhibiting a negative correlation with TVF (R2 = 0.45). Additionally, shading provided by plants and buildings manifests heterogeneity. At similar SVF levels, points predominantly shaded by plants (TVF > BVF) showcased lower Mean Radiant Temperature (MRT) and PET compared to points shaded mainly by buildings (BVF > TVF). The maximum reduction in air temperature and PET reached 1.1 °C and 1.2 °C, respectively. BVF exerted greater influence earlier in the morning, as solar altitude angle rises, the average thermal parameters of sites with BVF > TVF escalated rapidly until eventually surpassing sites with TVF > BVF. Last, superior thermal conditions were only ensured under high shading conditions. When the effective shading ratio of plants and buildings diminished (SVF > 0.3), the microclimate of measurement points might be impacted by the long-wave radiation from the underlying surface.

Determinants of subjective outdoor thermal comfort in an urban historic and cultural heritage landscape in Xi'an, China

In this study, we investigated factors related to subjective outdoor thermal comfort in the Ancient Ming Dynasty Walled City in Xi'an, China. Environmental data were collected from study sites by microclimate monitoring. Survey locations, demographics, psychological characteristics, thermal sensation vote (TSV), and thermal comfort vote (TCV) data were collected from 639 individuals in a questionnaire survey. Generalized linear regression analysis and path analysis were used to understand the associations between the TSV, environmental and psychological factors, and TCV. We found that green space locations, higher age, and greater subjective well-being and environmental satisfaction were associated with increased TCV. The universal thermal climate index was associated with TCV, and this association could have been affected by the individual's psychological state. Our findings suggest that environmental factors and psychological factors had non-negligible effects on the subjective thermal comfort of individuals located in an open urban area with historical and cultural significance.

Influence of landscape interventions on thermal comfort under time-varying building shadow; new Gwanghwamun square case, Seoul, South Korea

This study investigated the cooling effects of landscape interventions and their relative magnitude under hybrid urban context including time-varying building shadow cast. The study focused on the practical design alternatives, rather than experimental scenarios. We conducted outdoor thermal comfort (OTC) simulation using ENVI-met, and spatial-temporal comparison analysis for three green space expansion interventions for new Gwanghwamun square, Seoul, South Korea. In addition, we statistically analyzed the relationship between TCR (tree coverage ratio), GCR (green coverage ratio), WCR (water coverage ratio) and PET (Physiological Equivalent Temperature). The correlation and regression coefficients of the relationships under different building density, building locations and shadow cast conditions were compared. As a result of three interventions comparison, the comfort zone increased almost two times, while the discomfort zone decreased to ≈70% of the current condition in the long-term alternative. As TCR increases 22%, PET decreases up to 2.6 °C in average. Tree coverage ratio showed significant importance among the landscape elements. The influence of trees was slightly different for different contexts; larger cooling effect was found in no building shadow cast and low-density buildings. However, the difference was not noticeable; the influence of trees is still effective under building shadow cast and high-density buildings. Moreover, for high tree density area (TCR>50%), temporal gap of thermal comfort between measured time that mainly caused by building shadow change was greatly reduced compared to low tree density area (TCR<5%), which suggest the important role of tree in providing consistent thermal comfort. This study provides scientific evidence for trees' cooling effect and its relative magnitude under diverse built contexts of N-S oriented urban canyon. This study also contributes to developing an inclusive thermal comfort evaluation method based on both temporal and spatial scales for the effective comparison of real-world design alternatives.

Computer Vision Technology for Monitoring of Indoor and Outdoor Environments and HVAC Equipment: A Review

Artificial intelligence technologies such as computer vision (CV), machine learning, Internet of Things (IoT), and robotics have advanced rapidly in recent years. The new technologies provide non-contact measurements in three areas: indoor environmental monitoring, outdoor environ-mental monitoring, and equipment monitoring. This paper summarizes the specific applications of non-contact measurement based on infrared images and visible images in the areas of personnel skin temperature, position posture, the urban physical environment, building construction safety, and equipment operation status. At the same time, the challenges and opportunities associated with the application of CV technology are anticipated.

Thermal responses of face-masked pedestrians during summer: An outdoor investigation under tree-shaded areas

During the SARS-CoV-2 (COVID-19) pandemic, most citizens were cooperative towards the face-masking policy; however, undeniably, face masking has increased complaints of thermal discomfort to varying degrees and resulted in potential health hazards during summer. Thus, a thermal comfort survey was conducted under tree-shaded areas generally preferred by pedestrians to explore the thermal response of face-masked pedestrians. Thirty-two subjects, with and without masks, participated in walking experiments, and their thermal parameters and physiological indicators were recorded; moreover, the subjects were asked to fill in subjective questionnaires. The results showed that although tree shades significantly reduced the average radiant temperature, dampness in the mask may cause some discomfort symptoms, among which intense sweating (54.55%) and tachycardia (42.18%) accounted for the largest proportion. Based on thermal indices, it could be concluded that face-masking does not significantly affect the thermal comfort of subjects walking in shaded areas. Notably, a 30-min walk in tree-shaded areas with face masking does not adversely affect human health or quality of life. Thus, the present assessment of the thermal safety of humans in shaded environments provides reference data for determining thermal comfort levels during outdoor walking with face masking.

Discussion on regression analysis with small determination coefficient in human-environment researches

As the main indicator for assessing the explanatory strength of regression model, there is no denying that a bigger value of determination coefficient (R-squared, R² ) is the consistent pursuit of researchers in human-environment field, but whether to abandon or apply the model with a small value of R² is an ongoing argument. This paper summarizes three characteristics of human-environment researches (large number of various variables, large mathematical sample size, and polynomial regression model). Based on the mathematical mechanism of regression analysis, theoretical analysis and case study are combined to point out the misconceptions that are easy to step into and the corresponding suggested methods from three perspectives: selection of determination coefficients, consideration of independent variables, and application of regression models. An extraordinary important point is, if the regression model passes the significance test, even with a small coefficient of determination, it can still quantitatively explain the impact extent of independent variables on dependent variables, but cannot comprehensively and accurately predict the specific value of dependent variable based on existing independent variables; moreover, the larger the sample size, the closer the interpretation of dependent variables in local model to ideal model. It is expected that these cases and lessons could help researchers to better apply regression analysis in human-environment researches, and that the small value of R² would not be an excessive restriction affecting the development of scientific research in this field.

Exploring the Multisensory Interaction between Luminous, Thermal and Auditory Environments through the Spatial Promenade Experience: A Case Study of a University Campus in an Oasis Settlement

This paper aimed to develop a multisensory approach in a university campus, based on quantitative and qualitative approaches, investigating sense walk experiences (thermo-visual sound walk) under interactions of luminous, thermal, and auditory environments. The study was conducted in October 2021, in Chetma university campus in Biskra city, southern Algeria, which remains a famous oasis settlement of arid regions over the country. A comparative and correlation analysis was performed between the physical dimensions collected through a walking experience in three campus routes (outdoor, semi-outdoor and indoor). In addition, a multisensory survey of the walking experience on perceptual dimensions was evaluated in parallel to the empirical contribution. The paper shows that walkers’ thermal levels were balanced between neural and slightly hot in different spatial aspects. The glare was almost unperceived regarding the luminous conditions in the study site. The auditory experience reveals that the conducted points were generally quiet and well placed for educational requirements. Findings also show a strong relationship between the physical dimensions of the luminous and auditory environment. Furthermore, the findings suggest that the thermal and luminous environments are more perceptible than the auditory environment for the walkers of the outdoor and indoor routes. In contrast, the semi-outdoor route is often perceptible by the perceptual dimensions of the luminous and auditory environments. The findings on sensorial thresholds and spatial adaption are essential for the educational practices’ architectural and urban strategies for the Saharan cities and oasis settlements.