Mapping gaseous dimethylamine, trimethylamine, ammonia, and their particulate counterparts in marine atmospheres of China's marginal seas – Part 1: Differentiating marine emission from continental transport

Abstract. To study sea-derived gaseous amines, ammonia, and primary particulate aminium ions in the marine atmosphere of China's marginal seas, an onboard URG-9000D Ambient Ion Monitor-Ion Chromatograph (AIM-IC, Thermo Fisher) was set up on front deck R/V Dongfanghong-3 to semi-continuously measure spatiotemporal variations concentrations atmospheric trimethylamine (TMAgas), dimethylamine (DMAgas), ammonia (NH3gas) along with their matter (PM2.5) counterparts. In this study, we differentiated emissions gas species from continental transport using data obtained 9 22 December 2019 during cruise over Yellow Bohai facilitated by additional short-term measurements collected at a coastal site near Sea summer, fall, winter 2019. The sites demonstrated that observed TMAgas protonated (TMAH+) PM2.5 seas overwhelmingly originated sources. During cruise, no significant correlation (P>0.05) between simultaneously measured TMAH+ concentrations. Additionally, varied around 0.28±0.18 µg m−3 (average ± standard deviation), several episodic hourly average values exceeding 1 m−3, which were approximately order magnitude larger than those (approximately 0.031±0.009 m−3). Moreover, there negative (P<0.01) NH4+ PM2.5. Therefore, derived sea-spray aerosols. Using as tracers for basic gases ions, non-sea-derived DMAgas, NH3gas, non-sea-spray DMAH+ estimated. estimated each contributed 16 %, 34 65 % PM2.5, respectively. Uncertainties remained estimations, may decompose into smaller molecules seawater varying extents. likely long-range upwind continents based recorded offshore winds increased non-sea-salt SO42- (nss-SO42-) lack detectable increase DMAH+, NH4+, nss-SO42- SO2 plumes did not support secondary formation atmosphere.