Different formation pathways of nitrogen-containing organic compounds in aerosols and fog water in northern China

作者：Wei Sun, Xiaodong Hu, Yuzhen Fu, Guohua Zhang, Yujiao Zhu, Xinfeng Wang, Caiqing Yan, Likun Xue, He Meng, Bin Jiang, Yuhong Liao, Xinming Wang, Ping’an Peng, Xinhui Bi · 发表于：Atmospheric chemistry and physics · 年份：2024 · DOI：10.5194/acp-24-6987-2024 · 被引用次数：17 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate、Atmospheric aerosols and clouds

Abstract. While aqueous-phase processing is known to contribute to the formation of nitrogen-containing organic compounds (NOCs), the specific pathways involved remain poorly understood. In this study, we aimed to characterize the NOCs present in both pre-fog aerosols and fog water collected at a suburban site in northern China. Fourier-transform ion cyclotron resonance mass spectrometry was utilized to analyze the molecular composition of NOCs in both negative and positive modes of electrospray ionization (ESI− and ESI+). In both pre-fog aerosols and fog water samples, NOCs constituted a significant portion, accounting for over 60 % of all assigned formulas in ESI− and more than 80 % in ESI+. By comparing the molecular composition of NOCs originating from biomass burning, coal combustion, and vehicle emissions, we identified that 72.3 % of NOCs in pre-fog aerosols were attributed to primary anthropogenic sources (pNOCs), while the remaining NOCs were categorized as secondary NOCs formed within the aerosols (saNOCs). Unique NOCs found in fog water were classified as secondary NOCs formed within the fog water (sfNOCs). Through a comprehensive “precursor–product pair” screening involving 39 reaction pathways, we observed that the nitration reaction, the amine pathway, and the intramolecular N-heterocycle pathway of NH3 addition reactions contributed 43.6 %, 22.1 %, and 11.6 % of saNOCs, respectively. In contrast, these pathways contributed 26.8 %, 28.4 %, and 29.7 % of sfNOCs, ...