Characteristics of Aerosol Changes and Propagation Trajectory Analysis under Three Dust Storms—A Case Study of Gansu Province

In recent years, environmental concerns related to sand and dust emissions into the atmosphere have gained considerable attention due to shifts in global climate and ecological conditions. To track the spatial and temporal variations of soluble aerosols (UVAI) and particulate matter (PM_2.5), and to assess their impacts on human health during sand and dust storms of varying intensities, we developed daily scales using UVAI indicators derived from OMI data, complemented by high-altitude PM_2.5 measurements. The influence of meteorological conditions on the two substances was assessed using a Random Forest model, whereas the HYSPLIT model was employed to trace air mass movement trajectories on two dusty days, thereby identifying the dust sources. The results indicate that: ① During dusty weather conditions, areas with high UVAI are primarily concentrated in the western part of the study area. The relationship between the maximum UVAI values and the proportion of high-value areas is as follows: floating dust > sandstorm > sand lifting.② PM_2.5 concentration levels markedly increased across all three intensity categories during dust and sand events, with high-value areas progressively expanding from the northwestern region to the central and eastern parts of the study area. ③In our random forest regression model, V-wind speed and air temperature during each of the three dust storms significantly influenced UVAI trends; in contrast, cloud cover and relative humidity had a more pronounced impact on PM_2.5 trends.④The primary sources contributing to sandy and dusty weather remain largely consistent, primarily including the Taklamakan Desert and the Gurbantünggüt Desert. Secondary sources, however, show minor variations, specifically involving regions such as the Loess Plateau and the Gobi Desert along Mongolia's border, as well as the Qaidam Basin under sand-lifting conditions.