Organic aerosols (OA) have gained attention as a substantial component of atmospheric aerosols owing to their impact on atmospheric visibility, climate, and human health. Although oxygenated organic molecules (OOMs) are essential contributors to OA formation, the sources, transformations, and fates of the OOMs are not fully understood. Herein, anthropogenic OOMs (AOOMs), anthropogenic volatile organic compounds (AVOCs), and OA were concurrently measured in Xiamen, a coastal city in southeastern China. Our results show that the AOOMs exhibited a high nitrogen content (76%) and a low oxidation degree. Strong photochemical processes of aromatic VOCs were the predominant sources of AOOMs. Also, NOx concentrations and the occurrence of multigeneration OH radical oxidations were the critical factors that might influence the formation of AOOMs. Finally, the newly developed aerosol dynamic model's results show that more than 35% of the OA mass growth rate is attributed to the gas–particle partitioning of AOOMs. Further sensitivity testing demonstrates that the contribution of AOOMs to OA growth is significantly enhanced during high-particulate-concentration periods, especially under low-temperature conditions. This study emphasizes the vital role of photochemically produced AOOMs derived from AVOCs in OA growth in a coastal urban atmosphere.
有机气溶胶 （OA） 因其对大气能见度、气候和人类健康的影响而作为大气气溶胶的重要组成部分而受到关注。尽管含氧有机分子 （OOM） 是 OA 形成的重要贡献者，但 OOM 的来源、转化和命运尚不完全清楚。本文在中国东南沿海城市厦门同时测量了人为OOM（AOOMs）、人为挥发性有机化合物（AVOCs）和OA。结果表明，AOOMs的氮含量较高（76%），氧化程度较低。芳香族挥发性有机化合物的强光化学过程是AOOMs的主要来源。此外，NOx浓度和多代OH自由基氧化的发生是影响AOOM形成的关键因素。最后，新开发的气溶胶动力学模型的结果表明，超过35%的OA质量增长率归因于AOOM的气粒分配。进一步的灵敏度测试表明，在高颗粒物浓度期间，特别是在低温条件下，AOOM对OA生长的贡献显著增强。本研究强调了源自AVOCs的光化学产生的AOOMs在沿海城市大气OA生长中的重要作用。