Saltation–Sandblasting Processes Driving Enrichment of Water-Soluble Salts in Mineral Dust

Abstract

Dust aerosols over the Taklamakan Desert contain up to 3%−4% of soil-derived water-soluble sulfate, much higher than that in the soil. It has been hypothesized that this is due to aerosol−soil fractionation during dust emission. Here, we tested this hypothesis based on laboratory simulations of saltation and sandblasting processes. Two types of soil samples (sandy deserts and gravel deserts) were collected from the Taklamakan Desert, from which dust aerosols were generated for offline chemical analyses. We found that these laboratory-generated dust aerosols contain soil-derived watersoluble ions, and the contents are comparable to those measured in ambient dust but were several to hundreds of times those of the original soils. We argue that it is the fractionation in the saltation and sandblasting processes that led to the enrichment of watersoluble salt in dust aerosols. Our results provide the first geochemical constraints for understanding the origins of water-soluble ions in dust particles emitted from the Taklamakan Desert and the impact of chemical processing on dust composition during long-range transport.

Inhalable Fungi and Opportunistic Pathogens During Haze and Haze‐Dust Events From Winter to Springtime in One Typical Inland City of Northern China

“…Soil‐derived dust particles at their source areas are composed of insoluble components, such as quartz, clays, micas, feldspars, carbonates (primarily calcite, CaCO 3 ). During their transport in the atmosphere, they are frequently modified in composition through internal mixing with anthropogenic pollutants or by absorbing acidic gaseous species to produce salts, such as sulfate, nitrate, and chloride (Wu et al., 2022). The presence of water‐soluble ions can serve as an indicator of the potential source of particulate matter (Chen et al., 2022).…”

High Enrichment of Heavy Metals in Fine Particulate Matter through Dust Aerosol Generation

“…In addition, the chemical composition of soil particles can also vary with particle size. As smaller soil particles are more easily ejected, dust aerosol particles are unlikely to have exactly the same composition as their parent soils (Perlwitz et al, 2015;Wu et al, 2022). Dust deposited samples were the dust samples collected on the road or other surfaces using a brush and plastic tray (Shangguan et al, 2022), while dust aerosol samples were collected by filtering the air.…”