Seasonal Contribution of Isoprene-Derived Organosulfates to Total Water-Soluble Fine Particulate Organic Sulfur in the United States
Seasonal Contribution of Isoprene-Derived Organosulfates to Total Water-Soluble Fine Particulate Organic Sulfur in the United States
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DOI：
10.1021/acsearthspacechem.1c00102
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发表时间：
2021-08
影响因子：
3.4
通讯作者：
Yuzhi Chen;T. Dombek;J. Hand;Zhenfa Zhang;A. Gold;A. Ault;K. Levine;J. Surratt
中科院分区：
文献类型：
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作者：
Yuzhi Chen;T. Dombek;J. Hand;Zhenfa Zhang;A. Gold;A. Ault;K. Levine;J. Surratt
有机硫酸盐是大气细颗粒物（PM2.5）中含量最丰富的一类有机硫化合物。在全球范围内，异戊二烯衍生的OS（iOS）是报告最多的OS;然而，PM2.5中的总硫质量闭合尚未在分子水平上进行，以了解iOS的贡献如何随季节和美国的位置而变化。在这项工作中，在2016年夏季和冬季期间，从受保护视觉环境（IMPROVE）网络内部的20个地面站点收集的PM2.5中定量表征了iOS。总水溶性硫（TWS-S）和无机硫酸盐（Sinorg）的硫也进行了化学测定，TWS-S和Sinorg之间的不平衡作为水溶性有机硫浓度的上限估计。仅在夏季在大多数地点观察到显著较高的细颗粒有机硫浓度（TWS-S的20%），与美国东部的iOS浓度升高一致。平均而言，在美国东部，iOS（130 ng m-3）分别解释了29%和4%的有机硫和有机物（OM）质量。iOS（平均11 ng m-3）分别占OrgS和OM质量的6%和0.5%。在冬季，几乎没有检测到iOS，这与异戊二烯排放量减少一致。我们的研究表明，在美国东部和西部，在分子水平上仍然无法解释。这项研究为美国各地细颗粒物iOS的丰度、流行率和空间变异性提供了重要见解。
Organosulfates (OSs) are the most abundant class of organosulfur (OrgS) compounds in atmospheric fine particulate matter (PM2.5). Globally, isoprene-derived OSs (iOSs) are the most abundantly reported OSs; however, total sulfur mass closure in PM2.5has not been conducted at the molecular level in order to understand how iOS contributions vary by season and by location in the United States (U.S.). In this work, iOSs were quantitively characterized in PM2.5collected from 20 ground sites within the Interagency Monitoring of Protected Visual Environments (IMPROVE) network during the 2016 summer and winter seasons. Total water-soluble sulfur (TWS-S) and sulfur from inorganic sulfate (Sinorg) were also chemically determined, with the imbalance between TWS-S and Sinorgused as an upper-bound estimate of water-soluble OrgS concentrations. Significantly higher fine particulate OrgS concentrations (∼20% of TWS-S) were observed at most sites only in summer, coincident with elevated iOS concentrations in the eastern U.S. On average, iOSs (130 ng m–3) explained 29 and 4% by mass of OrgS and of organic matter (OM), respectively, in the eastern U.S. In the western U.S., iOSs (11 ng m–3, on average) accounted for 6 and 0.5% by mass of OrgS and OM, respectively. In winter, iOSs were hardly detected, consistent with reduced isoprene emissions. Our study shows that ∼70 and 80% of OrgS mass in the eastern U.S. and western U.S., respectively, remain unexplained at the molecular level. This study provides critical insights into the abundance, prevalence, and spatial variability of fine particulate iOSs across the U.S.