As cities increasingly endure hotter conditions, there is a critical need for reliable metrics that capture the cumulative and perceptual nature of pedestrian heat exposure. This study develops an integrated approach combining high-resolution urban Computational Fluid Dynmics (CFD) simulations with two complementary indices: a cumulative Heat Exposure Index and a Cooling Efficiency Index that quantify the magnitude, duration, and spatial variability of human heat stress. The analysis is applied to a tropical hot-humid neighborhood that includes a park, street trees, and lift-up buildings. Heat exposure is defined as the cumulative thermal load exceeding a specified UTCI (Universal Thermal Climate Index) threshold over time, weighted by the Dynamic Thermal Sensation (DTS) to better represent human perception. Cooling efficiency is calculated as the ratio of heat exposure between a test configuration and a reference scenario. This framework enables evaluation of both local and non-local effects on pedestrian comfort. Results show that unshaded areas can reach daily exposures of 700 °C.h, while shaded zones under trees achieve up to 40% reduction, though localized heating up to 25% may occur downwind of dense canopies. Among individual heat mitigation strategies, larger, densely positioned trees, as in parks, are shown to be the most effective, while trees should be avoided in ventilation corridors. The heat exposure index is also used to assess walkability by calculating cumulative thermal stress along pedestrian routes. The proposed approach establishes a reproducible methodology for quantifying cooling efficiency of heat mitigation strategies and translating thermal data into design-relevant indicators.
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