Nitrogen-containing organic compounds (NOC) formed from secondary organic aerosols (SOA) age via reaction with reduced nitrogen species are a vital class of brown carbon compounds. NOC compounds from ammonia (NH3) gas-aging of benzene SOA were investigated in present study, and the experiments were performed by irradiating benzene/CH3ONO/NO/NH3 air mixtures in a home-made smog chamber. The particulate NOC products of aged benzene SOA in the presence of NH3 were measured by UV-Vis spectrophotometer, attenuated total reflectance-Fourier transform infrared (ATR-FTIR), and aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with Fuzzy C-Means (FCM) clustering algorithm, respectively. Experimental results demonstrated that NH3 has significant promotion effect on benzene SOA formation. Organic ammonium salts, such as ammonium glyoxylate, ammonium 6-oxo-2,4-hexadienoiclate, which are formed from NH3 reactions with gaseous organic acids were detected as the major particulate NOC products of NH3-aged benzene SOA. 1H–imidazole, 1H–imidazole-2-carbaldehyde and other imidazole products via the heterogeneous reactions between NH3 and dialdehydes of benzene SOA were successfully detected as important brown carbon constituents. The formation of imidazole products suggests that some ambient particles contained organonitrogen compounds may be come from this mechanism. The results of this study may provide valuable information for discussing NH3 deposition and SOA aging mechanisms.

中文翻译：

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氨老化苯二次有机气溶胶褐碳成分表征

二次有机气溶胶 (SOA) 老化通过与还原的氮物质反应形成的含氮有机化合物 (NOC) 是一类重要的褐碳化合物。在本研究中研究了苯 SOA 的氨 (NH3) 气体老化中的 NOC 化合物，并通过在自制的烟雾室中照射苯/CH3ONO/NO/NH3 空气混合物来进行实验。用紫外-可见分光光度计、衰减全反射-傅立叶变换红外光谱（ATR-FTIR）和气溶胶激光飞行时间质谱仪（ALTOFMS）结合 Fuzzy 测量了在 NH3 存在下老化苯 SOA 的颗粒 NOC 产物。分别为 C-Means (FCM) 聚类算法。实验结果表明，NH3对苯SOA的形成有显着的促进作用。有机铵盐，例如乙醛酸铵，NH3 与气态有机酸反应形成的 6-oxo-2,4-hexadienoiclate 铵被检测为 NH3 老化苯 SOA 的主要颗粒 NOC 产物。1H-咪唑、1H-咪唑-2-甲醛和其他咪唑产物通过 NH3 与苯 SOA 的二醛之间的非均相反应被成功检测为重要的褐碳成分。咪唑产物的形成表明一些含有有机氮化合物的环境颗粒可能来自这种机制。这项研究的结果可能为讨论 NH3 沉积和 SOA 老化机制提供有价值的信息。1H-咪唑-2-甲醛和其他咪唑产物通过 NH3 与苯 SOA 的二醛之间的非均相反应被成功检测为重要的褐碳成分。咪唑产物的形成表明一些含有有机氮化合物的环境颗粒可能来自这种机制。这项研究的结果可能为讨论 NH3 沉积和 SOA 老化机制提供有价值的信息。1H-咪唑-2-甲醛和其他咪唑产物通过 NH3 与苯 SOA 的二醛之间的非均相反应被成功检测为重要的褐碳成分。咪唑产物的形成表明一些含有有机氮化合物的环境颗粒可能来自这种机制。这项研究的结果可能为讨论 NH3 沉积和 SOA 老化机制提供有价值的信息。