Street-level urban heat island mitigation: Assessing the cooling effect of green infrastructure using urban IoT sensor big data

With the growing interest in mitigating urban heat islands (UHIs), the cooling effects of green infrastructure (GI) have been extensively studied. Despite its importance, there is limited exploration of how GI improves street-level outdoor thermal comfort (OTC) for pedestrians. This study addresses this gap by examining how urban greenery and water bodies help alleviate Outdoor Thermal Comfort derived Urban Heat Islands (OTC-UHIs). Our study results indicate that GI significantly mitigates the OTC-UHIs in hot-humid summer conditions. Highly developed urban areas exhibit smaller land surface temperature differences between day and night due to high heat capacity in buildings and pavement, creating a tropical nighttime phenomenon. GI's cooling effects are greater in areas with higher vegetation cover, leading to a decrease in the OTC-UHI's intensity, frequency, and duration. The relationship between OTC-UHIs and urban morphology varies throughout the day, with vegetation cover ratio and sky view factors impacting cooling significantly. Additionally, cooling impact distance of GI follows a power curve relationship, with parks having a longer cooling impact distance compared to rivers, particularly at night. Our findings highlight that the effective usage of GI can significantly improve the street-level OTC of pedestrians by tackling the climate-induced UHIs.