Regenerating neighborhoods with nature-based solutions: assessment of pedestrian thermal comfort to support climate sensitive planning

In recent years, many cities have experienced high summer temperatures, with the entailed impact on health and wellbeing. Implementing climate-sensitive strategies has become crucial to address this challenge and improve thermal comfort and quality of life in cities. Green spaces have emerged as a particularly effective solution, providing cooling and multiple other benefits such as improved drainage systems and biodiversity. However, the implementation of adaptation measures is still slow due to several factors, including the lack of practical tools to facilitate their application. This study presents the preliminary results of a research project supporting the Department of Urban Planning of the Municipality of Trento, Italy, to facilitate urban regeneration with climate-responsive solutions. Specifically, the focus is on summer outdoor thermal comfort using multiscale qualitative and quantitative approaches. This paper investigates the variability of cooling effects given by green elements depending on their type and size. Design scenarios with different Nature-based Solutions (NbS) are assessed in terms of thermal comfort predictors in two neighborhood typologies (LCZ 5 and LCZ 8). The process of configuring the scenarios (green roofs, tree lines and green elements in parking lots) included workshops with decision-makers, in order to select solutions that could be applicable in the context and integrated into existing urban morphologies. A comprehensive assessment of the cooling intensity and duration was carried out, encompassing a comparative analysis of microclimate parameters and Physiological Equivalent Temperature (PET) across diverse scenarios within the two study areas. This approach was undertaken to determine the most effective configuration for each neighborhood. The indices are calculated with the Envi-met software tool and simulate a hot summer day. The findings are strongly practice-oriented as they provide a practical guideline to understand suitable solutions for the context and give directions on the necessary updates in the urban planning tools.