Mapping pedestrian heat stress in current and future heatwaves in Cardiff, Newport, and Wrexham in Wales, UK

Abstract

The paper describes a study that uses computer simulation to assess the extent of heat stress experienced by pedestrians in three Welsh cities during heatwaves, with a view to identifying implications for urban planning and design practice. The simulation model used localized radiant temperature, wind speed, air temperature, as well as the metabolic rate and clothing insulation of occupants. Simulated results were partially evaluated using field measurement data and from the Land Surface Temperature data obtained from Landsat satellite thermography. Results suggest that peak heat stress is expected to increase by 4.5 °C in Universal Thermal Climate Index equivalent temperature by 2080, especially for urban areas exposed to direct sunlight. The percentage of daytime hours without heat stress are expected to decrease significantly, from 30 to 80% in 2020 to 10–70% by 2080. The study suggests that mitigation measures are essential to reduce future heat stress in Welsh cities and towns; these include interventions such as green and blue infrastructure, choice of trees and artificial shading, choice of both artificial surface materials and vegetation cover, and street layout with proper orientation and aspect ratio. The results have significant implications for local authorities, town planning, and landscape practice.