Effect of freezing rain-induced changes in dry deposition on particulate matter concentrations in Hubei, China

Abstract Particulate matter (PM) pollution is a critical aspect of urban air quality degradation, and vegetation mitigates atmospheric PM concentrations via dry deposition, offering a natural, sustainable, and cost-effective strategy for pollution mitigation. Based on multi-source satellite remote sensing products, this study quantified the dry deposition effect of PM 2.5 and PM 10 on vegetation using a mathematical model, and evaluated its spatial and temporal changes in the long-term series in Hubei province, especially the impact of dry deposition changes induced by the extreme freezing rain process in early 2024 on particulate matter pollution. The key findings are as follows: (1) Leaf Area Index (LAI) showed a significant negative correlation with PM 2.5 and PM 10 , and modeled dry deposition flux (DDF) showed consistent coherence with LAI, Land Surface Temperature (LST), Wind Speed (WS), and Precipitation (PRE) at the one-month scale; (2) The physical damage caused by the freezing rain substantially diminished the vegetation’s capacity for particulate matter deposition, with the reduction of the deposition effect of PM 10 being more pronounced than that of PM 2.5 ; (3) A decadal spatiotemporal analysis of dry deposition on vegetation indicated an overall trend toward improving air quality in Hubei and further revealed stronger spatial heterogeneity in the long-term trend of PM 2.5 dry-deposition reduction than that of PM 10 , partly reflecting differences in regional socioeconomic and industrial activity and background PM concentrations. This study advances a deeper understanding of the influence of extreme weather events on vegetation-driven dry deposition and provides scientific support for air quality management and strategic development aimed at strengthening urban ecosystem resilience.