Characterization of Volatile Organic Compounds Over the Eastern Seas of China in Winter

Volatile organic compounds (VOCs) are important atmospheric species that regulate the formation of both ozone and secondary organic aerosol. Compared with continental environments, VOC species, concentration and origins in marine environments were much less understood. Here, we conducted a 2-month VOCs measurement using a proton-transfer-reaction mass spectrometer during the cruise of DongFangHong III research vessel over the eastern oceanic areas of China in winter 2019. According to the location of DongFangHong III, we divided our cruise into five regions: Qingdao port (QD), Zhoushan port (ZS), Bohai Sea (BHS), Yellow Sea (YS), and East China Sea (ECS). For most individual VOCs, their concentration exhibited the trend of ZS > QD > BHS > YS > ECS. A decreasing tendency was also found when the measurement location was progressively farther away from the coastline. Further, we performed Positive Matrix Factorization and retrieved five distinct VOC sources, including shipping emission, DongFangHong III emission, regional background, aged transport, and port and nearshore emission. Contributions of these five factors varied depending on the location, influenced by emission, atmospheric oxidation, and meteorological conditions. In addition, the inland anthropogenic sources were found to have a larger contribution than oceanic ones. Overall, by conducting in situ measurements of VOCs and source apportionment, this study complements the lack of information on the speciation, abundance, and sources of VOCs in the marine environment of China.