Organic aerosol (OA) is a complex mixture of compounds with diverse elemental and structural features, and its composition affects its health and environmental impacts. A detailed speciation of the functional group distribution in OA is important for constraining atmospheric reaction pathways and products, evaluating chemical mechanisms and models, and understanding OA impacts. We used high-resolution tandem mass spectrometry to perform a nontargeted analysis of OA functional groups from three diverse ambient sites across times of day and seasons. We observed a range of oxygen-, nitrogen-, and/or sulfur-containing functional groups, including oxygenates such as hydroxyls (29–69%) and carboxylic acids (19–59%), that dominated the functional group distribution and that may participate in hydrogen bonding and thus impact the chemical and physical properties of OA (percentages indicate average ion abundance contributions across campaigns). We also observed esters (7–39%) and ethers (13–42%) that suggest the importance of oligomerization. On average, organonitrates represented only 12% of identified nitrogen-containing groups and organosulfates represented 21% of identified sulfur-containing groups, while we observed many other nitrogen- and/or sulfur-containing structures that were important contributors to OA composition (e.g., amines, imines, nitrophenols, and sulfides). Most compounds (81%) were multifunctional and likely multigenerational oxidation products, which typically contained two to five functional groups in total.

中文翻译：

---

非目标串联质谱分析揭示了跨多个站点，季节和一天中的时间的气溶胶功能组的多样性和可变性

有机气溶胶（OA）是具有多种元素和结构特征的化合物的复杂混合物，其组成会影响其健康和环境影响。OA中官能团分布的详细形态对于限制大气反应途径和产物，评估化学机理和模型以及了解OA影响非常重要。我们使用高分辨率串联质谱在一天中和每个季节的不同时间对来自三个不同环境位置的OA功能组进行非目标分析。我们观察到一系列含氧，氮和/或硫的官能团，包括含氧化合物，例如羟基（29-69％）和羧酸（19-59％），占主导地位的官能团分布，并可能参与氢键作用，从而影响OA的化学和物理性质（百分比表示整个运动中平均离子丰度贡献）。我们还观察到酯（7–39％）和醚（13–42％）表明低聚的重要性。平均而言，有机硝酸盐仅占已鉴定的含氮基团的12％，有机硫酸盐占已鉴定的含硫基团的21％，而我们观察到许多其他的含氮和/或硫结构对OA组成起重要作用（例如，胺，亚胺，硝基酚和硫化物）。大多数化合物（81％）是多功能的，可能是多代的氧化产物，通常总共包含2至5个官能团。