Importance of Oxidants and Temperature in the Formation of Biogenic Organosulfates and Nitrooxy Organosulfates
Importance of Oxidants and Temperature in the Formation of Biogenic Organosulfates and Nitrooxy Organosulfates
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DOI：
10.1021/acsearthspacechem.1c00204
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发表时间：
2021-09-06
影响因子：
3.4
通讯作者：
Hamilton, Jacqueline F.
中科院分区：
文献类型：
--
作者：
Bryant, Daniel J.;Elzein, Atallah;Hamilton, Jacqueline F.
生物二次有机气溶胶（BSOA）在有机气溶胶中占很大比例，其形成化学、成分和物理性质可能受到人为排放的影响，特别是在城市地区。有机硫酸盐 (OS) 是 BSOA 的一类重要示踪剂，在过去十年中得到了充分研究，但仍缺乏对昼夜变化的详细环境研究。在这项研究中，夏季和冬季期间，在中国广州的一个城市地点每天收集八次细颗粒物样本。广州深受生物和人为排放的影响，因此可以研究生物与人为的相互作用。使用超高效液相色谱串联质谱 (UHPLC-MS2) 分析源自单萜和异戊二烯的单个 OS 和硝基氧基 OS (NOS) 物种，并使用三种真实标准和代理标准进行定量。观察结果显示单萜衍生的 OS 和 NOS 存在强烈的昼夜变化，在夜间达到峰值，浓度从傍晚开始增加，凸显了 NO3 氧化化学的作用。异戊二烯衍生的 OSs/NOSs 显示出强烈的季节性特征，夏季和冬季平均浓度分别为 181.8 和 69.5 ng m(-3)，在温度高于 30°C 时呈指数增加。低 NO 形成途径在夏季占主导地位，而高 NO 途径在冬季变得更加重要。异戊二烯 OS 的形成强烈依赖于颗粒硫酸盐 (SO42-) 的可用性，表明氧化异戊二烯物质具有广泛的异质化学性质。总体而言，这项研究为在高度人为影响的环境中生物源性 OS 和 NOS 的形成提供了进一步的见解。
Biogenic secondary organic aerosol (BSOA) makes up a significant proportion of organic aerosol, and its formation chemistry, composition, and physical properties can be influenced by anthropogenic emissions, especially in urban areas. Organosulfates (OSs) are an important class of tracers for BSOA and have been well-studied over the past decade, although detailed ambient studies of diurnal variations are still lacking. In this study, fine particulate matter samples were collected eight times a day across summer and winter campaigns at an urban site in Guangzhou, China. Guangzhou is heavily influenced by both biogenic and anthropogenic emissions, allowing for biogenic-anthropogenic interactions to be studied. Individual OSs and nitrooxy OSs (NOSs) species derived from monoterpenes and isoprene were analyzed using ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS2) and quantified using three authentic and proxy standards. The observations show strong diurnal variations of monoterpene derived OSs and NOSs, which peaked during the night, with concentrations increasing from the early evening, highlighting the role of NO3-oxidation chemistry. Isoprene derived OSs/NOSs showed strong seasonal profiles, with summer and winter average concentrations of 181.8 and 69.5 ng m(-3), respectively, with exponential increases observed at temperatures above 30 degrees C. Low-NO formation pathways were dominant in the summer, while high-NO pathways became more important in the winter. Isoprene OS formation was strongly dependent on the availability of particulate sulfate (SO42-), suggesting an extensive heterogeneous chemistry of oxidized isoprene species. Overall, this study provides further insights into biogenically derived OS and NOS formation within highly anthropogenically influenced environments.