Urban Thermal Comfort Research Articles

Dynamic response of vegetation, land surface temperature and carbon storage to changes in land use and land cover in Mysuru City, Karnataka, India.

Land use and land cover (LULC) changes are associated with notable environmental concerns, such as alterations in land surface temperature, loss of vegetation and the impact on carbon sequestration, especially within urban settings. Urban planners worldwide are investigating these impacts. A study utilizing remote sensing and geographic information system techniques examined changes in land surface temperature (LST), normalized difference vegetation index (NDVI) and carbon sequestration in Mysuru City from 1992 to 2022. The results showed a 2.39% decrease in vegetation cover and a substantial 36.97% increase in urban areas, leading to elevated LST by an average of 4°C. Carbon storage has significantly declined to 25Mgha-1 in 2022 from 56Mgha-1 in 1992. The spatial extent of zero-level carbon storage has steadily diminished over the years. The analysis indicates a negative relationship between LST and carbon storage, with a weak correlation explained by a coefficient of determination (R2) value of 0.063 in 1992 and 0.024 in 2022. Conversely, a positive relationship exists between the NDVI and carbon storage, suggesting that effective strategies such as afforestation, reforestation and urban greening practices can enhance carbon sequestration capacity and mitigate climate change impacts in rapidly growing cities. The results of this study offer valuable insights for city planners and policymakers, aiding in the identification of areas experiencing increased LST and diminishing natural landscapes. Furthermore, the study can serve as a foundation for identifying urban hotspots, cold spots and areas conducive to urban thermal comfort. The results of this study can be enhanced by using a higher spatial resolution satellite dataset, thus providing a prospect for future research.

Mapping facade materials utilizing zero-shot segmentation for applications in urban microclimate research

To address the Urban Heat Island (UHI) effect—a significant urban climate challenge—detailed urban microclimate modeling is essential. Such modeling typically requires data on urban surface properties and morphologies from street canyons and buildings. Most urban surveying efforts have focused on morphological attributes such as sky view factor, vegetation or building surface ratio, while the mass-collection of facade materials has been hindered by the complexity of the segmentation task and the need for large and diverse labeled datasets. Recognizing the importance of mapping facade materials for urban thermal comfort, envelope heat emissions, and building energy studies, we employ computer vision-based state-of-the-art zero-shot learning paradigms for high-fidelity facade material extraction. Our approach circumvents the traditional need for extensive labeled training data, allowing for adaptation to a variety of urban contexts and material types. Tested in Dubai, Amsterdam, and Boston (three architecturally diverse cities), our algorithm successfully detects the predominant facade material in 68% of cases and identifies the top three present material classes in 85% of cases. Additionally, we show how material coverage identification is crucial for assessing outdoor thermal comfort, as evident in shifts in annual cold and heat stress hours across the climates of the three cities in a sample urban canyon.

Thermal Comfort and Afforestation In Belém: City of Mango Trees and Host Of COP 30

Objective: The objective of this article is to evaluate the thermal comfort in Belém based on climatic variation and afforestation, considering its relationship with public policies from the administration of Antônio Lemos to the current period. The analysis is based on historical and climatic data, as well as afforestation indicators, and seeks to understand how these policies contribute to urban sustainability and the fulfillment of SDG 11 goals. Theoretical Framework: The work is based on the concepts of Sustainable Development, with an emphasis on the dynamics of cities and urban management, considering the context of public policies aimed at environmental management. Aspects related to thermal comfort in the face of climatic variations are addressed, as well as the relevance of urban afforestation as a mitigating strategy. The study is set in the context of Belém, the host city of COP 30, highlighting the importance of sustainable practices and integrated urban policies to face contemporary environmental challenges. Method: The method adopted in the study combines a theoretical and literature review covering physiographic, climatic and historical aspects related to the territorial and urban formation of Belém, with a focus on thermal comfort, climate change, afforestation and the city's green areas. As a complement, tables, charts and graphs are used to analyze data collected from secondary sources, including the Environmental Index Indicators for Brazil's Capitals and the 2010 Municipal Basic Information Survey (Munic), published by the IBGE (2024). In addition, temperature variations in the city are analyzed, based on records from the National Institute of Meteorology (INMET). Results and Discussion: The results show a variation of 1.96°C in the maximum temperature in Belém between 1970 and 2023, indicating a growing trend of thermal warming. This evolution highlights the need for integrated and effective responses to limit global warming to 1.5°C, through adaptation and mitigation measures. Public policies for sustainable urban planning, expanding green areas and encouraging resilient practices are essential strategies for mitigating the impacts of rising temperatures. This study seeks to contribute to the debate on the challenges and possibilities of implementing the Sustainable Development Goals (SDGs) in Brazilian urban contexts, especially in cities in the Amazon region. Research Implications: The thermal rise identified intensifies the impacts on urban thermal comfort, increasing vulnerability to heat waves, health problems and pressure on infrastructure. This reality reinforces the urgency of adaptation and mitigation measures, such as sustainable urban planning, expansion of green areas and resilient practices to contain the effects of warming. Hosting COP 30 in Belém is an opportunity for international projection and a turning point for urban and environmental management, which can catalyze public policies, modernize planning instruments and encourage greater social participation in decisions that affect the population. Originality/Value: This study contributes to broadening the debate on the challenges and possibilities of implementing the SDGs in Brazilian cities, especially in the Amazon. It highlights the importance of holding COP 30 in Belém, considering sustainable urban development as a collective process that requires collaboration between governments, civil society and international actors, aiming for global goals, quality of life and socio-environmental justice.

Effect of Blue–Green Infrastructure in Mitigating Microenvironmental Heat Islands: Field- and Simulation-Based Insights

Urban heat island (UHI) effects, intensified by urbanization and environmental changes, are critical challenges to urban thermal comfort and sustainability. This study investigates the combined role of water bodies and vegetation in mitigating microclimatic heat island effects within a campus area, focusing on their cooling impacts and interactions. Using field measurements and numerical simulations, the research evaluates the cooling effects and wind flow modifications induced by greenery and water bodies in the surrounding environment. The findings demonstrate that both vegetation and water bodies provide a significant cooling effect, reducing temperatures by 0–6 K in downstream regions, with the impact being more pronounced closer to the blue–green spaces. Furthermore, the combined application of water bodies and vegetation offers enhanced cooling effects; however, their influence on the thermal environment exhibits a nonlinear relationship. These results underscore the importance of strategic blue–green infrastructure planning in mitigating UHI effects and optimizing urban thermal environments.

ENVI-met Simulation of Green Plant Layouts for Urban Thermal Comfort Optimization

ENVI-met Simulation of Green Plant Layouts for Urban Thermal Comfort Optimization

Configurações urbanas, fatores socioeconômicos e conforto térmico em São José do Rio Preto, SP

This study investigates the relationship between environmental comfort and urban socio-spatial settings in the city of São José do Rio Preto. The method consists of the analysis and thermal characterization of four urban areas in the city: two in areas characterized by high building standards and two in areas of special social interest. Campaigns to collect data on temperature and air humidity were carried out simultaneously, using reports from passersby about their perception and satisfaction with the thermal environment. The Physiological Equivalent Temperature (PET) climatic index was calculated, and reports on perception and satisfaction with the thermal environment were statistically analyzed in terms of the physical characteristics of the adopted urban areas. The contributions may lead to reflections on possible relationships between socioeconomic factors and urban thermal comfort conditions. Questions related to the Sky View Factor, the direction and speed of the wind, and the availability of outdoor areas are decisive for the variation of PET and user satisfaction reports on the thermal environment in the four urban areas. The analysis and discussion of this study reaffirmed the importance of considering climate issues in urban planning. To achieve this, the aim is to contribute with analyses that can help formulate proposals for future improvements.

Dual impacts of solar-reflective façades in high-density urban areas on building energy use and outdoor thermal environments

Dual impacts of solar-reflective façades in high-density urban areas on building energy use and outdoor thermal environments

Impact of Affordability on Urban Thermal Comfort: a Thermal Analysis of the Center of Gurupi-TO

Objective: Investigate the differences in temperature and relative humidity at different points in the central region of Gurupi-To, with the aim of understanding the impact of urban afforestation on the local temperature and humidity of the city, based on the difference in existing tree vegetation. Theoretical Framework: It is based on concepts of phytosociology and urban afforestation, highlighting that the uncontrolled growth of cities causes environmental damage that impacts people's lives. Thus, the increase in temperature results from climate change and is affected by the artificial built environment due to the difference in construction materials and vegetation. Urban afforestation is a means to mitigate this issue and improve the microclimate. Method: The methodology adopted for this research includes fieldwork with the collection of temperature and air humidity data, using the Datalogger device, model GGL-20, between March and April 2021. The comparison was conducted through graphical representation of variance (ANOVA), based on T-test analysis, using the R Studio software. Results and Discussion: The results obtained revealed that among the points studied, the area with the most vegetation showed lower temperatures and better humidity levels in locations with more urban afforestation. This is due to the vegetative cover, as trees provide shade and contribute to evapotranspiration, a physiological process that positively impacts the improvement of temperature and air humidity factors. Research Implications: The practical and theoretical implications of this research are discussed, providing results that influence conservation practices and the sustainable management of urban afforestation. Originality/Value: This study contributes to the literature by presenting a practical investigation into the influence of urban afforestation on temperature and air humidity in cities located in the Cerrado biome, with a focus on Gurupi-TO. It highlights the importance of conservation and management of urban afforestation in urban areas. The relevance and value of this research are evidenced by the data and the proposed strategies, which aim to demonstrate the importance of expanding urban afforestation in city centers as a mechanism for controlling the microclimate, particularly temperature and air humidity.

Seasonal dynamics of land surface temperature and urban thermal comfort with land use land cover pattern in semi-arid Indian cities: Insights for sustainable Urban Management

Seasonal dynamics of land surface temperature and urban thermal comfort with land use land cover pattern in semi-arid Indian cities: Insights for sustainable Urban Management

Urban Canyon Design with Aspect Ratio and Street Tree Placement for Enhanced Thermal Comfort: A Comprehensive Thermal Comfort Assessment Accounting for Gender and Age in Seoul, Republic of Korea

Rapid urbanization and increased human activity have negatively impacted the microclimate of cities, leading to unfavorable conditions for human thermal comfort, particularly in outdoor spaces. Thermal comfort can be improved through various means, such as adjusting the height of urban buildings, the aspect ratio of road widths, and the placement of street trees. This study employed the ENVI-met software V5.5.1 to simulate the microclimate based on aspect ratio (H/W = 1.5) and street tree spacing (6 m) similar to actual conditions with different aspect ratios (H/W = 0.5, 1.0, and 2.0) and street tree spacing (2 m) in Seoul, Republic of Korea. Thermal comfort was assessed through a comprehensive predicted mean vote (PMV) evaluation, considering the gender (male and female) and age (8, 35, and 80 years) of residents in the target area, to determine the optimal urban canyon scenario. The results of the study indicated that the height of the building and the percentage of trees had a significant impact on the temperature and PMV results. When comparing PMV results, women have higher thermal vulnerability than men, and based on age, older adults have higher thermal vulnerability. The aspect ratio of 1.5 and tree spacing of 2 m resulted in the lowest temperature of 35.91 °C at 12:00 p.m. at 0° wind direction and 36.09 °C at 90° wind direction, lower than the actual input value of 36.9 °C. The PMV values were also under the same conditions, with an average PMV by gender of 3.87 at 0° and 4.21 at 90° and an average PMV by age of 3.86 at 0° and 4.19 at 90°. This finding is significant because it can inform the development of planned cities that prioritize urban thermal comfort during summer. This can be achieved through the strategic design of urban canyons and incorporation of street trees in both new and existing cities.

The Relationship between Green Infrastructure and Air Pollution, History, Development, and Evolution: A Bibliometric Review

In response to the challenge of atmospheric pollution posed by growing environmental problems, this study reviews and analyzes the research status and development trends of green infrastructure (GI) in improving air pollution from 2014 to 2024. Using the CiteSpace tool, we explore research hotspots, disciplinary developments, significant contributors, and influential literature in this field, identifying current research gaps and predicting future trends. The findings indicate that GI significantly impacts the reduction of air pollution, the regulation of urban microclimates, and the enhancement of ecosystem services. However, existing studies often focus on isolated aspects and lack comprehensive assessments. Moreover, the research trajectory in this field shows a declining trend. Future research should emphasize interdisciplinary integration, combining ecology, urban planning, meteorology, and public health. By utilizing advanced technologies, such as drones, remote sensing, AI, and big data analysis, we can improve data accuracy and the generalizability of research findings. Additionally, it is crucial to consider the performance of GI under different climatic conditions and socio-economic contexts to comprehensively quantify its overall benefits in terms of air quality, urban thermal comfort, public health, and economic impact. This comprehensive approach will provide a scientific basis for policy-making and urban planning.

Impact of land use and land cover change on land surface temperature: Comparative studies in four cities in southwestern Ethiopia

Impact of land use and land cover change on land surface temperature: Comparative studies in four cities in southwestern Ethiopia

Enhancing Sustainable Thermal Comfort of Tropical Urban Buildings with Indoor Plants

Rapid urbanization exacerbates the urban heat island effect, raising local temperatures and endangering residents’ health and well-being. The decreasing green spaces resulting from urbanization necessitate global action focused on reducing heat island intensity and addressing heat stress. Urban green infrastructure (UGI) offers solutions for enhanced comfort and reduced pollution through passive methods. Various large-scale UGI projects have been implemented to regulate temperature and improve air quality in urban areas. More research on smaller green spaces is essential to improve the microclimate in space-constrained urban cities. This experimental study examines the thermal effectiveness of potted plants located on balconies of a mid-rise residential building in Chennai, India. The study aims to enlighten balcony greening’s role in reducing heat stress by monitoring temperature and humidity indoors and outdoors, with and without potted plants at similar solar radiation. Potted plants significantly lowered indoor air and surface temperatures by about 3 °C. Thus, balconies offer untapped potential for green interventions that are often unnoticed in tropical climates like India. The challenges in the installation and maintenance of UGI hinder the widespread adoption of UGI even though UGI positively influences residential well-being. The significant findings benefit urban planners and architects, enlightening strategies to enhance urban thermal comfort and mitigate heat stress through small-scale and cost-effective green interventions. This research contributes to sustainable urban development in tropical climates, aligning with several UN Sustainable Development Goals (SDGs), including SDGs 3, 7, 11, 13, and 15.

CFD simulation of the wind flow under lift-up buildings using a porous approach

CFD simulation of the wind flow under lift-up buildings using a porous approach

Spatiotemporal Evolution in the Thermal Environment and Impact Analysis of Drivers in the Beijing–Tianjin–Hebei Urban Agglomeration of China from 2000 to 2020

As urbanization advances, the issue of urban heat islands (UHIs) grows increasingly serious, with UHIs gradually transitioning into regional urban heat islands. There is still a lack of research on the evolution and drivers of the thermal environment in urban agglomerations; therefore, in this study, we used trend analysis methods and spatial statistical analysis tools to investigate these issues in the Beijing–Tianjin–Hebei (BTH) urban agglomeration. The results demonstrated the following: (1) The land surface temperature (LST) exhibited low fluctuation, while the relative land surface temperature (RLST) fluctuated significantly. In Zhangjiakou and Chengde, the LST and RLST evolution trends were complex, and the results differed between daytime and nighttime, as well as between the annual and seasonal scales. In other regions, the trends of LST and RLST evolution were more obvious. (2) During the daytime, the high UHI clusters centered on “BJ–TJ–LF” and “SJZ–XT–HD” formed gradually; during the nighttime, the high UHI clusters were mainly observed in built-up areas. The distribution range and direction of UHIs showed greater degrees of evolution during the daytime in summer. (3) The total UHI area showed an increasing trend, and the intensity of heat stress suffered by the BTH agglomeration was increasing. (4) In BTH and Hebei, aerosol optical depth, surface solar radiation, population density, and gross domestic product were the dominant factors influencing UHIs; moreover, in Beijing and Tianjin, all factors showed an basically equal impact. The methodology and findings of this study hold significant implications for guiding urban construction, optimizing urban structure, and improving urban thermal comfort in the BTH urban agglomeration.

Strategic tree placement for urban cooling: A novel optimisation approach for desired microclimate outcomes

Trees are crucial elements for improving urban microclimates by providing cooling through shading, evapotranspiration, and windbreaks. To maximise their cooling effects, it is essential to strategically position the trees in optimal locations. However, research on optimising tree location and its impact on microclimates is limited owing to computational challenges and costs. This study introduces a novel method that employs three optimisation algorithms—i.e., Non-dominated Sorting Genetic Algorithm II (NSGA-II), Particle Swarm Optimisation (PSO), and Ant Colony Optimisation (ACO)—to identify the optimal locations for trees in urban environments to enhance urban thermal comfort. The research methodology involves simulating microclimate responses to tree placements optimised by each algorithm and assessing the results based on urban thermal comfort. The results underscore the efficacy of optimised tree locations, demonstrating that optimising tree locations can significantly reduce the Universal Thermal Comfort Index (UTCI) in urban areas. Furthermore, the findings suggest that the clustering of tree canopies has a compounding impact on these cooling benefits in urban areas. Notably, all three algorithms significantly improved UTCI. PSO demonstrated the rapid identification of effective tree configurations. However, ACO provided the most substantial reduction in air temperature, highlighting its potential as an effective tool for urban cooling. While efficient, NSGA-II plateaued earlier, suggesting its utility in scenarios where timely solutions are crucial.

Analysis of the correlation mechanism between geometric parameters and the thermal environment of Xi'an's summer outdoor commercial pedestrian streets.

Intensive urban development has resulted in the degradation of the urban thermal environment in most regions. There is a growing consensus on the need to enhance urban thermal comfort through well-designed forms, especially in open spaces like urban canyons. To address this, our study focuses on Xi'an's commercial pedestrian streets, employing K-means clustering analysis to create 32 representative models based on actual scenes, capturing their textural characteristics. Simultaneously, 11 geometric indicators (2D/3D) were chosen to quantify the canyon's geometric form. We assessed the spatial and temporal distribution differences in the thermal environment across these models using Envi-met simulation. Finally, Spearman correlation analysis was employed to examine the correlation and significance of the two sets of indicators, culminating in formulating an ideal model. The findings reveal that (1) wind conditions are predominantly influenced by the canyon's geometric form, followed by solar radiation and temperature, with the lowest relative humidity change amplitude among the assessed thermal parameters. (2) Among the 11 geometric form indicators, 3D indicators correlate more significantly with thermal environment parameters than 2D indicators. Specifically, street orientation significantly impacts the thermal environment, Build-To-Line Rat holds greater significance than interface density, and both building shape coefficient and block surface ratio are significantly correlated with air temperature and wind speed, with a weaker correlation to solar radiation. (3) In the Xi'an region, courtyards oriented north-south demonstrate a more favorable trend in the thermal environment.

A satellite-based approach for thermal comfort simulation: A case study in the GBA

A satellite-based approach for thermal comfort simulation: A case study in the GBA

Study on Microclimate and Thermal Comfort in Small Urban Green Spaces in Tokyo, Japan—A Case Study of Chuo Ward

Small urban green spaces are abundant in densely populated urban areas, but little is known about their impact on the urban heat island effect and thermal comfort. Therefore, this study selected as research sites four small urban green spaces in a typical high-density built-up area, Chuo Ward in Tokyo, Japan. The ENVI-met software 5.1.1 simulation method was used to analyze these sites’ microclimate and thermal comfort conditions. The following are the results: (1) Small urban green spaces significantly reduce urban air temperatures, particularly during hot weather, with temperature reductions ranging from 2.40 °C to 2.67 °C, consistently lower than the highest temperatures in Tokyo’s Chuo Ward, mainly between 1:00 and 2:00 p.m. (2) Thermal comfort analysis indicates that small urban green spaces can significantly improve urban thermal comfort during the day, particularly around noon, by reducing one or two thermal comfort levels compared to typical urban street blocks. However, these differences gradually diminish throughout the evening and night, and thermal comfort inside and outside green spaces becomes more uniform. (3) Green space size is not the only factor influencing thermal comfort; the layout of plants within the green space and the layout of the surrounding buildings also have an impact. Despite their small size, even small green spaces can significantly enhance comfort. This study highlights the need to promote urban sustainability through the extensive integration of small green spaces in dense urban environments. Small green spaces can serve as a high-frequency, low-cost solution for environmental sustainability by addressing the increasingly severe urban heat island effect as well as environmental challenges that in the urbanization process.

Seasonal characteristics of outdoor thermal comfort and residential electricity consumption: A Snapshot in Bangkok Metropolitan Area

Seasonal characteristics of outdoor thermal comfort and residential electricity consumption: A Snapshot in Bangkok Metropolitan Area