Sustainable placemaking and thermal comfort conditions in urban spaces: the case study of Avenida dos Aliados and Praça da Liberdade (Porto, Portugal)

Abstract

The urban microclimate of Avenida dos Aliados and Praça da Liberdade was subjected to comprehensive examination through twelve measurement campaigns at six strategic observation points over the course of two seasons, namely summer and winter, between 2019 and 2020. The study employed an objective approach based on measurements to evaluate key microclimatic factors, including air temperature, which ranged from 15 ◦C in winter to a peak of 38 ◦C in summer, and Relative Humidity (RH), which varied from 50% to 85%. Additionally, wind speed was recorded between 1.0 m/s and 2.5 m/s, along with solar radiation levels, which significantly impacted Surface Temperatures (Tsurf), reaching up to 38.0 ◦C in some areas. A parallel subjective survey questionnaire was conducted with 123 participants. In particular, the preference for shaded areas was highlighted through a thermal sensation map, with some places in Praça da Liberdade being a favored spot during summer due to its vegetation and lower Tsurf. The study identified solar exposure, wind patterns, and Tsurf as the key determinants of thermal comfort. It is noteworthy that shaded areas, particularly those with a substantial amount of greenery, were found to alleviate discomfort from the heat, thereby making them the preferred choice for pedestrians. Furthermore, the study underscored the significance of incorporating adaptive elements, such as greenery, shading structures, and ventilation corridors, into urban design to enhance comfort across different seasons. Results contribute with valuable insights for urban planners. The data indicate that urban design should prioritize the inclusion of pedestrian-friendly elements, such as shaded walkways and seating areas, to promote the active use of public spaces. This approach is particularly relevant in the context of climate change, where seasonal variations and increasing temperatures may exacerbate discomfort in urban environments.