This study investigates the impacts of five aircraft-based artificial rain enhancement operations conducted across Jiangsu Province during 3—9 November 2023 on local and regional air quality.Flight operation records were integrated with data from the Jiangsu provincial meteorological observation network and concurrent hourly environmental monitoring of particulate matter (PM_2.5 and PM₁₀) and gaseous pollutants (SO₂,NO₂,O₃,and CO) to evaluate both precipitation enhancement effectiveness and its influence on atmospheric pollutant concentrations.Periods affected by seeding were identified through the spatial and temporal overlap between aircraft flight tracks and the targeted cloud regions,along with the estimated downwind influence window.Monitoring sites located within these regions were designated as “impacted stations”,while a control area comprising control stations—chosen to represent similar meteorological and environmental conditions but unaffected by seeding—served as a baseline for comparison.
For each operation,pollutant concentrations and their change ratios during the seeding period were computed and contrastedbetween impacted and control stations.This comparative approach helps isolate the influence of seeding-induced precipitation from background variability due to synoptic changes or emission fluctuations.Results show that artificial precipitation enhancement significantly increased observed rainfall and was accompanied by marked reductions in particulate concentrations,with effects persistingseveral hours after rainfall onset.In the representative case on 3 November,PM_2.5,PM₁₀,and O₃ mass concentrations decreased for approximately 4—7 hours,indicating that wet scavenging processes remained active during and shortly after precipitation.Across the five operations,all monitored pollutants exhibited varying degrees of decline,with the most consistent and pronounced reductions observed for PM_2.5,PM₁₀,and O₃.Peak reductions during periods of intense precipitation reached approximately 90％,while more moderate events also yielded notable declines relative to pre-rainfall baselines.
Compared to gaseous pollutants,particulate matter displayed a stronger and more consistent response to precipitation.Both the absolute decreases and normalized change ratios of PM_2.5 and PM₁₀ were larger at impacted stations than at control stations,with differences amplifying as precipitation duration increased.This dependence suggests enhanced removal efficiency under prolonged rainfall,consistent with established wet-scavenging mechanisms.Specifically,in-cloud nucleation scavenging removes aerosols that activate into cloud droplets,while below-cloud collection processes—impaction,interception,and,diffusion—efficiently eliminate remaining aerosols as raindrops descend through the boundary layer.Gaseous pollutants exhibited weaker and more variable responses,reflecting differences in solubility,reactivity,and boundary-layer dynamics.
Uncertainties remain due to the limited sample size (five operations over one week) and potential confounding from concurrent synoptic variability,spatial heterogeneity in emissions,and boundary-layer evolutions.Nevertheless,converging evidence—including temporal alignment between rainfall and pollutant declines,stronger effects at impacted sites,and dependence on precipitation duration—indicates that aircraft-based cloud seeding can provide short-term but measurable air-quality benefits through enhanced wet removal of PM_2.5 and PM₁₀.These findings underscore the potential co-benefits of precipitation enhancement for pollution mitigation and highlight the need for expanded,multi-seasonal analyses supported by high-resolution microphysical and dispersion modeling.