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

• Published in: Atmospheric chemistry and physics 2021-11, Vol.21 (21), p.16413-16425
• Main Authors: Chen, Dihui, Shen, Yanjie, Wang, Juntao, Gao, Yang, Gao, Huiwang, Yao, Xiaohong
• Format: Article
• Language: English
• Subjects: Aerosols; Air pollution; Air-sea interaction; Amines; Ammonia; Atmosphere; Chemical analysis; Chromatography; Correlation; Cruises; Emission analysis; Emissions; Gases; Ions; Long-range transport; Marginal seas; Measurement techniques; Nitrogen; Offshore; Particulate emissions; Particulate matter; Plumes; Sea-water; Seawater; Spray; Sulfur dioxide; Suspended particulate matter; Temperature effects; Tracers; Transport; Trimethylamine; Water analysis; Winds
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-21-16413-2021

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 the front deck of the R/V Dongfanghong-3 to semi-continuously measure the spatiotemporal variations in the concentrations of atmospheric trimethylamine (TMAgas), dimethylamine (DMAgas), and ammonia (NH3gas) along with their particulate matter (PM2.5) counterparts. In this study, we differentiated marine emissions of the gas species from continental transport using data obtained from 9 to 22 December 2019 during the cruise over the Yellow and Bohai seas, facilitated by additional short-term measurements collected at a coastal site near the Yellow Sea during the summer, fall, and winter of 2019. The data obtained from the cruise and coastal sites demonstrated that the observed TMAgas and protonated trimethylamine (TMAH+) in PM2.5 over the Yellow and Bohai seas overwhelmingly originated from marine sources. During the cruise, no significant correlation (P>0.05) was observed between the simultaneously measured TMAH+ and TMAgas concentrations. Additionally, the concentrations of TMAH+ in the marine atmosphere varied around 0.28±0.18 µg m−3 (average ± standard deviation), with several episodic hourly average values exceeding 1 µg m−3, which were approximately 1 order of magnitude larger than those of TMAgas (approximately 0.031±0.009 µg m−3). Moreover, there was a significant negative correlation (P