Monitoring dust retention variations in different functional zones based on leaf magnetism and the influence of green belt spatial layouts on leaf dust retention

Atmospheric particulate pollution generated by traffic activities poses a threat to human health. Due to their unique structure and function, plant leaves efficiently capture and accumulate atmospheric particulate matter, acting as natural particulate collectors. This study focuses on leaf samples from different functional zones in Jinhua City, Zhejiang Province, employing environmental magnetism methods to explore dust retention differences among zones and the impact of green belt spatial layouts on dust retention. The results indicate that leaf magnetism is an effective method for monitoring traffic-related particulate pollution. The saturation isothermal remanent magnetization per unit area (2D-SIRM) values of leaf samples from traffic zones were significantly higher than those from residential areas; the 2D-SIRM value of tree leaves increases with higher traffic volume, indicating more dust retention, suggesting that traffic activities are a major source of particulate pollution. Leaf height (height above the ground), distance from roads, and orientation significantly influence dust retention, with higher magnetic mineral concentrations found in leaves facing roads, closer to roads, and at a height of 2 m, suggesting that traffic-emitted particulates tend to accumulate in these areas. There are differences in dust retention capacities among tree species; Osmanthus and Loropetalum chinense perform better than Golden Privet and Red Tip Photinia. The research results provide some reference for the design of roadside green vegetation systems in Jinhua City and other cities in subtropical monsoon climate zones.