Urban nature-based solutions for particulate matter reduction and thermal comfort enhancement: Empirical evidence from Guangdong Province

Rapid urbanization in warm and humid coastal regions has intensified exposure to particulate matter and outdoor heat stress, with significant implications for public health and energy demand. This article examines how urban nature-based solutions, including street trees, pocket parks, green roofs and integrated green corridors, influence particulate matter concentrations and outdoor thermal comfort in major cities of Guangdong Province. The study combines multi-year measurements from fixed and mobile monitoring stations with detailed urban morphology mapping and microclimate observations in representative street canyons, residential blocks and mixed-use districts. Thermal comfort is characterized using established human biometeorological indices, and particulate matter is measured at pedestrian height along paired nature-based solution and reference transects. Results indicate that well-designed nature-based solutions reduce daytime particulate matter concentrations by up to one third and lower mean radiant temperature by up to two degrees Celsius, with the largest benefits occurring in connected green corridors that combine shading and ventilation.