2026-10-14T17:33:06Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34046560 2026-10-01T15:18:06Z category_4 category_13 category_272 category_873 category_39 category_69 category_132 category_133 portal_63 item_type_6 month_year_10_2026

Particulate Amine Salts as Dynamic Hubs for Atmospheric Nitrogen Exchange Weina Zhang (128757) Jiale Lao (22225804) Shangyu Zhu (25157137) Yuemeng Ji (1480276) Guiying Li (1480285) Jie Zhong (39213) Joseph S. Francisco (1414543) Taicheng An (1480282) Biochemistry Genetics Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology Inorganic Chemistry Infectious Diseases Plant Biology sulfates dramatically accelerate subsequent oxidation process resolution mass spectrometry produces volatile species findings fundamentally revise atmospheric particulate matter salts instead serve particulate amine salts oxidized amine salts previously unrecognized nitrogen 3 </ sub 2 </ sub organic nitrogen nitrogen exchange nitrogen deposition • oh yields low volatility amides remote ecosystems remote background remaining 52 release source range transport preferentially remain particle phase nonvolatile sinks missing sources mediated pathways magnitude compared latter branch gas phase efficiently initiated dynamic hubs chemically inert bifurcated fate aged particles Amine salts in atmospheric particulate matter have long been regarded as chemically inert and nonvolatile sinks for organic nitrogen. Here, we overturn this paradigm by demonstrating that these salts instead serve as dynamic hubs for nitrogen exchange. By using integrated ab initio calculations and high-resolution mass spectrometry, we show that dimethylamine (DMA) and trimethylamine (TMA) salts are efficiently initiated by •OH, generating reactive radical cation intermediates, which is not considered in previous organic nitrate chemistry. Meanwhile, sulfates dramatically accelerate the subsequent oxidation process by lowering free energy barriers by orders of magnitude compared to water-mediated pathways. Quantitative branching ratios reveal a bifurcated fate for oxidized amine salts: over 47.5% yields low-volatility amides (CH₂NCHO and (CH₃)₂NCHO) that preferentially remain in the particle phase, and the remaining 52.5% produces volatile species (CH₃NH₂ and CH₃NC) that partition to the gas phase. The latter branch is a previously unrecognized nitrogen re-release source, which explains the missing sources of HCN in remote background and amide in aged particles. These findings fundamentally revise the role of particulate amine salts in atmospheric organic nitrogen budgets, long-range transport, and nitrogen deposition in remote ecosystems. 2026-10-01T00:00:00Z Text Journal contribution 10.1021/jacs.6c10698.s001 https://figshare.com/articles/journal_contribution/Particulate_Amine_Salts_as_Dynamic_Hubs_for_Atmospheric_Nitrogen_Exchange/34046560 CC BY-NC 4.0