Heat exposure and coping strategies for food delivery riders under urban heat extremes

Global warming and heatwaves have intensified heat exposure risks for outdoor workers. The food delivery riders, as a rapidly expanding outdoor working occupation, face more serious threats from the exposure of urban heat extremes due to the nature of work, particularly during peak ordering hours in midday. Nevertheless, research specifically targeting the heat exposure risks of the food delivery occupation remains scant. Taking a bustling commercial area in Nanjing (China) as an example, this study aims to systematically evaluate the spatial and temporal distribution of heat exposure in urban streets to quantify the heat exposure risk for delivery riders. The SOLWEIG (Solar and Longwave Environmental Irradiance Geometry) model was used to simulate the Mean Radiant Temperature (Tmrt), and GPS data to assess the transient and cumulative heat stress experienced by individual delivery riders. Results show that factors like shading, street type, and orientation significantly impact the thermal environment of urban streets. Heat mitigation strategies include enhancing shading with building and tree covers (resulting in an average reduction of 10.6 to 21.1℃ in Tmrt), increasing the proportion of north–south routes (in the northern hemisphere), and integrating alternative delivery routes. These measures can improve transient heat stress by 15.5% and cumulative heat stress by 13.2% for food delivery riders. Moreover, comprehensive coping strategies are proposed from multiple perspectives (i.e., urban planning, platform management, and individuals) to minimize the individual heat exposure and corresponding traffic accidents for the food delivery occupation, which further promotes the sustainable development of the urban environment, transportation and delivery industry.