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• Awareness and knowledge of heat impact reduction were lower than perceived severity. • Heat-induced psychological impacts were more common than physiological impacts. • Men were more vulnerable in physiological impacts and daily functioning disruption. • Economic condition was not a critical factor affecting heat-related responses. • Younger generation had not well prepared for urban heat challenges. Urban heat, the combined effect of heatwaves and urban heat islands (UHIs), is a severe challenge for many cities around the world. While there have been numerous studies on urban heat, society's understanding of it is still insufficient, hindering its mitigation and adaptation. This paper aims to investigate people's vulnerability to, and perception, awareness and knowledge of, urban heat. A questionnaire survey was conducted with 562 respondents in the hot and humid city of Chongqing, China in the summer of 2020. Data were analysed using descriptive statistics, Mann-Whitney U test, Kruskal-Wallis H test and logistic regression. Results indicated that urban heat is generally understood as having a moderate severity, while there is limited knowledge of heat-related risks. The perceived heat-related psychological impacts are more severe than physiological impacts. There is limited awareness and knowledge of heat-impact reduction methods. Nevertheless, people's awareness, perception and knowledge of urban heat increase once they suffer heat-induced impacts, indicating exposure/experience-driven awareness and knowledge. Moreover, climate injustice among different groups (e.g. gender, age, education, income, health) of people related to heat challenges was identified. People's perception, vulnerability, awareness and knowledge increased with age, but interestingly decreased with increasing education level and improved health conditions. Economic factor was not critical to heat-related responses. Men could be more vulnerable to physiological symptoms and daily functioning than women. The results of this study provide an understanding of urban heat perception and adaptive knowledge, enabling practitioners and policy makers to formulate effective urban heat mitigation and adaptation policies and regulations. [ABSTRACT FROM AUTHOR]

• This paper develops a framework for urban heat prevention, mitigation and adaptation. • Air-conditioning systems are the dominant cooling facility in both work and living environments. • Urban planning and design for heat resilient cities is the most urgent intervention. • 50% of the respondents preferred collaborative payment among government, developers, and owners for heat resilient infrastructure. • Heat-related responses and actions towards urban heat challenges were dependent demographic factors and their exposure, habit formation and behavior change, social acceptance. This study investigates public participation in heat impact reduction by analysing adaptive behaviours, familiarity with urban heat island (UHI) and cooling strategies, the perceived urgency of heat impact actions and citizen's willingness to pay through a questionnaire survey in Chongqing, China. The results indicate that air-conditioning systems are the dominant cooling facility in both work and living environments. Respondents had a moderately familiar understanding of several cooling strategies such as urban vegetation, shading devices, water-based artificial facilities, urban design for shading and ventilation and water bodies. Familiarity with innovative materials and techniques for pavements, roofs and façades was less than moderate. Urban planning and design for heat resilient cities was thought to be the most urgent intervention, followed by the establishment of temporary cooling facilities. Most respondents indicated that cost-sharing mechanisms for urban heat prevention and control systems should at least include the government, whilst 50% of the respondents preferred collaborative payment among government, developers, and owners. Only 41.6% of the interviewees expressed their willingness to pay, with a share varying between <20 and >80 RMB. A conservative estimate indicated that there could be an average payment of 45.95 RMB and 19.10 RMB among the 234 respondents who were willing to pay and all 562 respondents regardless of willingness, respectively. Respondents' heat-related responses and actions towards urban heat challenges were dependent on a wide range of factors like gender, age, education, economic status, health, exposure, habit formation and behavior change, social acceptance, etc. Moreover, such factors could interact with each other affecting public behavior with different weights. Overall, this study increases our understanding of people's perceptions and proactiveness in reducing urban heat and provides guidance for decision-makers towards a novel user-aware approach to the implementation of urban heat prevention, adaptation, and mitigation strategies. [ABSTRACT FROM AUTHOR]

• The effects of landscape composition on LST increased from 2000 to 2019. • The effects of landscape configuration on LST differs in different cities. • Reorganizing landscape configuration was applicable in relieving UHI. • The distributions of SUHI in three cities are roughly parallel to the Yangtze River. The urban heat island (UHI) phenomenon, arising from rapid urbanization, has attracted both social and academic attention because of its effects on citizens' daily life. This paper investigated the relationship between landscape composition and configuration, population and land surface temperature (LST) in three megacities along the Yangtze River, aiming at providing useful information to reduce the effect of UHI. A correlation analysis and ordinary least squares (OLS) models were used to discover the relationship between these indices. The results showed that the effects of landscape composition, especially impervious surfaces (IS), on the LST increased obviously from 2000 to 2019. The correlation coefficients of the density of IS increased from 0.608 to 0.839 in Nanjing, from 0.368 to 0.777 in Wuhan, and from 0.416 to 0.874 in Chongqing, respectively. On contrast, the effects of landscape configuration on LST differs in different cities. In Nanjing, small and scattered patches of green spaces showed the highest capacity in cooling the surrounding areas. In Wuhan, small patches of waterbodies owned the highest cooling effect. While in Chongqing, small and scattered patches of forest with irregular shapes showed the highest cooling effect. The findings proved that reorganizing landscape configuration was applicable in relieving UHI. [ABSTRACT FROM AUTHOR]

• On-site measurements were conducted to investigate the synergistic cooling effects (SCEs). • The littoral forest yielded more than 3.3 °C cooling effect than that of the separate trees. • The air temperature differences depended strongly on land cover features of each site. • As the LAI of littoral trees decreased 1.0, the average SCE increased by 0.19∼0.31 °C. Both green and blue space are found to be effective for urban heat mitigation and air quality improvement. However, studies on the Synergistic Cooling Effects (SCEs) of green-blue spaces are limited. This paper aims to investigate the SCEs of green-blue spaces in Chongqing, a typical hot humid city in China, through the field measurement and numerical simulation. First, air temperature and relative humidity over different land-use sites (forest, lawn, and impervious pavement) were measured with and without water simultaneously, from July to August 2018. Experimental results revealed the SCEs of green-blue spaces were obvious in 7–12 m surrounding waterfront areas, where the mean air temperature reduction was 3.3 °C higher than the sums of cooling effect of standalone water and forest. Additionally, an ENVI-met model was validated against the measured data before conducting simulation for the study area in five scenarios, including one control group with no trees and four greening cases with different Leaf Area Index (LAI) values to investigate the importance of green infrastructure on the waterfront thermal environment. Simulation results showed that a decrease of 1.0 LAI can lead to a reduction of average air temperature by 0.19–0.31 °C, possibly owing to the enhanced ventilation flow. [ABSTRACT FROM AUTHOR]