Urban Green Spaces Under Climate Warming: Controlling the Spread of Allergenic Pollution Through Residential Area Spatial Layout Optimization

In response to the demands of climate change and urban sustainability, urban green space construction in China has rapidly expanded, while simultaneously giving rise to allergenic pollen pollution. Focusing on the central urban area of Xi’an, Shaanxi Province, China, this study utilizes urban surveys, field measurements, and pollen particle microscopy to analyze the seasonal variation in allergenic pollen pollution concentrations and the physical dispersion characteristics of allergenic pollen particles in residential areas. The study also examines the impact of urban residential area spatial layout on regulating allergenic pollen pollution. The results show that (1) allergenic pollen pollution in Xi’an’s residential areas exhibits significant seasonal characteristics, with spring, summer, and autumn being the primary seasons. The highest concentrations occur in spring, dominated by tree pollen, followed by summer and autumn with a predominance of herbaceous pollen. (2) Pollution concentrations in residential areas are affected by the diurnal temperature variation, with higher concentrations observed in public green spaces compared to residential green spaces and roadside green spaces. (3) Allergenic pollen pollution shows a layered characteristic in the vertical direction, with concentrations concentrated around 13 m above ground due to the effects of diurnal temperature variation and local microclimate. (4) Urban pollen pollution concentrations are positively correlated with high temperatures and negatively correlated with high humidity, while local circulations influence pollen dispersion concentrations in residential areas. (5) Design indicators such as plot ratio and building stagger affect the dispersion concentrations of allergenic pollen pollution in residential areas. The findings provide a scientific basis for optimizing residential area spatial design to mitigate allergenic pollen pollution and offer strategic guidance for improving the health and livability of urban environments.