One of our master students civil engineering student, Gianluca Belardo, has now finished his MSc thesis, expanding on the results from thermal walks. He also developed site specific recommendations for each of the locations tested and check their feasibility with the municipality Hengelo. The title is 'Urban Heat Stress Assessment in Hengelo Through Thermal Walks to Guide the Implementation of Green-Blue Infrastructure for Urban Cooling'. The summary is below, and the repository link to
download the full thesis is here. An overview of the tested locations is in the image.
"Since the 1940s, global temperatures have steadily increased as a result of climate change. At the same time, rapid urbanisation has driven cities to expand, replacing natural landscapes with built-up areas dominated by materials like concrete and asphalt. These surfaces absorb and retain heat, while the loss of vegetation reduces the natural cooling capacity of the environment. As urban areas grow denser and greener spaces become more limited, cities begin to experience significantly higher temperatures than their rural surroundings, a phenomenon known as the Urban Heat Island (UHI) effect. This rise in urban temperatures not only worsens environmental conditions but also poses growing risks to public health and overall quality of life.
This thesis explores how urban design interventions, specifically Green-Blue Infrastructure (GBI), can improve outdoor thermal comfort in city centres. The research focuses on Hengelo, a medium-sized city in the Netherlands that, like many European cities, is increasingly dealing with the consequences of extreme heat, yet lacks detailed microclimate data or clear strategies for site-specific interventions. While Hengelo has made some progress in implementing GBI, many public spaces remain exposed to heat stress, and decision-makers face challenges in balancing spatial constraints, public use, and climate adaptation goals.
To address these challenges, the thesis first evaluates the existing conditions in Hengelo’s urban centre and then proposes targeted GBI strategies to improve thermal comfort in its most heat-stressed areas. This begins with a comprehensive literature review, examining the UHI effect, thermal comfort theory, and the effectiveness of various GBI types in mitigating urban heat in different spatial contexts. The review also explores participatory and observational methods for assessing heat perception, laying the foundation for the fieldwork approach adopted in this thesis.
Building on insights from the literature, the methodology integrates multiple research approaches that shaped both the data collection and the analysis of findings. A spatial analysis was first conducted using the available urban heat maps for Hengelo, helping to identify priority areas that might benefit most from interventions. Due to the low spatial resolution of these maps, assumptions had to be made about which areas were most heat-stressed, based on available information on urban form, surface materials, and existing vegetation. To build on this preliminary assessment, the core of the field research involved thermal walks, a novel method in which participants walked through five different locations while environmental data was recorded and subjective thermal perceptions were gathered. Environmental conditions were measured using two Kestrel 5400 trackers. At each location, one tracker was placed at a reference point and the other at an intervention point to assess the cooling performance of the existing GBI. At the same time, participants at the intervention point completed a questionnaire covering comfort ratings, thermal sensation, and preferences for shade, wind, and cooling.
The results showed a strong correlation between dense green infrastructure and improved thermal comfort. The location with the most dense tree cover recorded a reduction in Physiological Equivalent Temperature (PET) of over 20°C between reference and intervention points and was consistently rated as the most comfortable by participants. Locations with partial vegetation, also showed moderate cooling effects and improved participant comfort. In contrast, blue infrastructure without shade, such as the pond and the fountain locations, produced limited physical relief. Tracker data even showed PET increases in some cases due to radiant heat from surrounding paving or water reflections, despite participants perceiving these areas as slightly cooler, likely due to the psychological effects of water.
After this analysis, a strategy was developed to improve the less effective locations analysed in the thermal walks and also for the most heat stressed areas that were analysed at an earlier stage. The study then included feedback from municipal representatives, who helped assess the feasibility of the proposed interventions. While some locations, such as the pond area, were deemed realistic for near-term implementation (adding climbing vegetation), all others locations posed challenges due to underground infrastructure and competing land uses. Additionally, the municipality emphasized the importance of maintaining visual openness and ecological balance, where new trees could disrupt existing plant life. As a result, the recommendations reflect not only environmental performance but also practical limitations. The discussion with the municipal representatives also sparked internal reflection within the municipality about whether long-term heat resilience should take precedence over occasional public uses in certain urban spaces.
Based on the findings, this thesis recommends a site-specific approach to urban cooling. Priority should be given to increasing shade through tree planting where feasible, combining green and blue infrastructure in areas with enough space, and using artificial shading (e.g. pergolas or vertical greenery) in more constrained locations. Overall, the research shows that evidence-based interventions, informed by local context, can support effective climate adaptation. Moreover the methodology applied here, specifically the use of thermal walks, builds on existing research and demonstrates their value in connecting environmental data with user experience. In doing so, this study contributes new, location-specific insights and helps further develop the practical application of thermal walks in urban heat research."
