Urban heat stress in the context of socioeconomic and environmental challenges: Heat risk analysis and online surveys in northwestern Portugal

The issue of Urban Heat Stress (UHS) is becoming increasingly critical, with the rising frequency and intensity of heatwaves serving to exacerbate the problem. It is of the utmost importance to gain insight into the preparedness levels of urban populations if we are to foster resilient cities. However, research on the perceived impacts of heat among city dwellers remains limited, particularly studies that integrate both objective and subjective assessments. To address this gap in the literature, a survey was conducted in Porto and Braga, two major cities in northwestern Portugal, after categorising the risk levels associated with extreme heat. The objective of the survey was to identify personal characteristics associated with knowledge about heatwave protection and preferred communication channels for receiving related information. The online household survey yielded 613 responses, with 365 from Braga and 248 from Porto. It focused on how different socioeconomic groups are impacted by heat stress and the relationship between perceived heat impacts and indicators of exposure and vulnerability across the different groups. The findings indicated that demographic groups typically perceived as vulnerable exhibited the highest levels of exposure and susceptibility to heat stress. The study indicates that respondents identified health authorities and civil protection agents as principal sources of information during extreme heat events. This emphasises the significance of targeted communication strategies aimed at vulnerable groups through these channels to enhance their comprehension of heatwave protection measures. These insights can facilitate the enhancement of urban resilience and the reduction of the impact of UHS, underscoring the necessity for policymakers to adopt more refined strategies in managing heat stress in urban environments.