Urban green infrastructures to improve pedestrian thermal comfort: A systematic review

Evidence of heat mitigation through green infrastructure has been extensively documented and quantified in the literature; however, the effectiveness of implementing these strategies regarding thermal comfort at the pedestrian level has not received the same attention. Thus, this paper aims to investigate the role of UGI strategies on pedestrian the thermal comfort in different climatic contexts. Seventy-six peer-reviewed studies were included, analysed and synthesised for their (i) methodological approaches, (ii) pedestrian-level heat mitigation effects. It is seen that there is a positive association of UGI with pedestrian thermal comfort in temperate, continental, arid and tropical climates. Concerning to heat mitigation effects, street trees, green spaces and green walls have great cooling potential. However, green roofs have a negligible effect at the pedestrian level. The evolution of the role of the UGI for pedestrian thermal comfort in different climatic zones reveals the need to develop urban projects based on choosing the “right tree in the right place”. Furthermore, the challenges of evaluating the heat mitigation performance of the UGI require procedures to compensate for psychological influences on thermal perception and standardized monitoring protocols to increase the reliability of the results and allow comparisons between different studies.