Urban thermal comfort: Mitigation of heat islands in the north-south corridor of 18th and 19th Streets, Pasto

Abstract

The study analyzed the presence and magnitude of the urban heat island (UHI) phenomenon in the north-south road corridor of Pasto during the period 2013-2023. Historical records from urban and rural weather stations were used, complemented with direct measurements using a digital thermo-hygrometer at 45 strategic points in the study area. The results showed thermal differences of up to 3.9 °C between urban and rural areas, as well as internal contrasts of 3.7 °C over distances of less than one kilometer. These variations were related to building density, the predominant use of impervious surfaces and low vegetation cover. An upward trend in maximum temperatures and a decrease in minimum temperatures was identified, accompanied by a 24% reduction in wind speed and a progressive increase in solar radiation. The inverse correlation between temperature and relative humidity, confirmed by a Pearson coefficient of -0.73, showed the importance of vegetation and permeable soils in microclimatic regulation. Sectors with more trees and shade showed cooler and more humid microclimates, while paved areas intensified thermal storage. The mitigation proposal included passive strategies such as strategic tree planting, five-story buildings with staggered morphology, and the use of high albedo and low thermal inertia materials in pavements and roofs. The implementation of these measures reduced the average temperature by 2.76 °C and increased relative humidity by 5.75%. These interventions demonstrated that sustainable urban planning can improve thermal comfort, reduce areas of discomfort by up to 74% and provide effective solutions to climate change.