A Review of Water-Soluble Ions in Natural Dust Particles Over East Asia: Abundance, Spatial Distributions, and Implications

Mineral dust from deserts is a major natural aerosol type, significantly influenced by water-soluble ions (WSIs). These ions modulate the dust’s radiative properties and its contribution to the deposition of bioavailable nutrients, thereby shaping regional and global climate processes as well as marine ecosystem dynamics. This review synthesizes current research on the variations of major WSIs in dust particles transported from desert regions to downstream marine areas over East Asia. In source regions and adjacent areas, WSIs typically account for 4% to 14% of dust mass, dominated by mineral salts including SO42–, Cl–, Na+, and Ca2+. As dust moves into the populated areas of northern China, the WSIs is still dominated by mineral sources, while substantial secondary SO42–, NO3– and NH4+ can be observed particularly in reversely transported dust plumes. In the coastal areas of eastern China, similar trends are observed, with additional sea salt contributions under marine air influence. When dust plumes reach Korea and Japan, dust particles often have higher proportions of SO42– and NO3–, mixed with sea salt, with WSIs in fine particles sometimes exceeding 30% of the mass. These changes of WSIs in Asian dust particles during their long-distance transport highlight the dynamic physicochemical properties of dust aerosols, their climatic and environmental effects, as well as the accompanying health risks. The review concludes with a discussion of key research challenges in quantifying WSIs in long-distance transporting Asian dust and understanding their implications.