Chemical characteristics and source of water-soluble ion in atmospheric aerosol over the marginal seas of the western North Pacific

High-resolution observations of total suspended particulates (TSP) were carried out during the 9th Chinese National Arctic Research Expedition (CHINARE) using the online ion chromatography monitoring system for aerosol and gas components over the marginal seas of the western North Pacific in July, 2018. Concentrations of water soluble inorganic ions(WSI), including ${\mathrm{SO}}_4^{2-} $, Na+, Cl−, F−, Br−, ${\mathrm{NO}}_3^- $, ${\mathrm{NH}}_4^+ $, K+, Ca2+, Mg2+, ${\mathrm{NO}}_2^- $ and ${\mathrm{CH}}_3{\mathrm{SO}}_3^- $(MSA) were analyzed, and the main sources of these ions were discussed by a series of methods. The mean concentration of main WSI in aerosols over the East Asian Sea Area and the northern marginal sea of the Pacific Ocean was (11.35 ± 9.95) μg/m3 and (10.28 ± 8.88) μg/m3, respectively. The mean concentration of MSA over the East Asian Sea Area and the northern marginal sea of the Pacific Ocean was (0.06 ± 0.04) μg/m3 and (0.17 ± 0.16) μg/m3, respectively, and the mean concentration of nss-${\mathrm{SO}}_4^{2-} $ was (5.83 ± 8.44) μg/m3and (0.71 ± 0.70) μg/m3, respectively, which indicates that the East Asian Sea Area was severely influenced by the anthropogenic sources. The PMF results showed that the WSI in the East Asian Sea Area was mainly affected by sea salt sources (48%), secondary sources (36%) and biological sources (16%), and the WSI in the northern marginal sea of the Pacific Ocean was mainly influenced by sea salt sources (58%), terrestrial inputs (24%) and biological sources (18%). The dry deposition fluxes of ${\mathrm{NO}}_3^- $ and ${\mathrm{NH}}_4^+ $ in the East Asian Sea Area [(1.74 ± 1.22) mg/(m2·d)] were obviously higher than the northern marginal sea of the Pacific Ocean [(0.86 ± 0.30) mg/(m2·d)]. The research is of great significance for better understanding the sources and composition of marine aerosols comprehensively recognizing the circulation of marine aerosols in marine ecosystems, and scientifically evaluating the role of marine aerosols in global climate change.