Neutral polyfluoroalkyl substances in the atmosphere over the northern South China Sea

Neutral Polyfluoroalkyl substances (PFASs) in the atmosphere were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. Four groups of PFASs, i.e., fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAs), fluorooctane sulfonamides (FOSAs) and fluorooctane sulfonamidoethanols (FASEs), were detected in gas samples. FTOHs was the predominant PFAS group, accounting for 95.2-99.3% of total PFASs (Sigma PFASs), while the other PFASs accounted for a small fraction of Sigma PFASs. The concentrations of PFASs ranged from 18.0 to 109.9 pg m(-3) with an average of 54.5 pg m(-3). The concentrations are comparable to those reported in other marine atmosphere. Higher concentrations of PFASs were observed in the continental-influenced samples than those in other samples, pointing to the substantial contribution of anthropogenic sources. Long-range transport is suggested to be a major pathway for introducing gaseous PFASs into the atmosphere over the northern SCS. In order to further understand the fate of gaseous PFASs during transport, the atmospheric decay of neutral PFASs under the influence of reaction with OH radicals and atmospheric physical processes were estimated. Concentrations of 8:2 FTOH, 6:2 FTOH and MeFBSE from selected source region to the atmosphere over the SCS after long-range transport were predicted and compared with the observed concentrations. It suggests that the reaction with OH radicals may play an important role in the atmospheric decay of PFAS during long-range transport, especially for shorted-lived species. Moreover, the influence of atmospheric physical processes on the decay of PFAS should be further considered. (C) 2016 Elsevier Ltd. All rights reserved.

2013年9月至10月在南海北部的一次航测活动中对大气中的中性多氟烷基物质（PFASs）进行了测量。在气体样本中检测到了四类PFASs，即氟调聚物醇（FTOHs）、氟调聚物丙烯酸酯（FTAs）、氟辛烷磺酰胺（FOSAs）和氟辛烷磺酰胺基乙醇（FASEs）。FTOHs是主要的PFAS类别，占PFASs总量（∑PFASs）的95.2% - 99.3%，而其他PFASs在∑PFASs中所占比例较小。PFASs的浓度范围为18.0至109.9皮克/立方米，平均为54.5皮克/立方米。这些浓度与其他海洋大气中所报道的浓度相当。在受大陆影响的样本中观察到的PFASs浓度高于其他样本，这表明人为源的重大贡献。长距离传输被认为是将气态PFASs引入南海北部大气的主要途径。为了进一步了解气态PFASs在传输过程中的归宿，估算了在与羟基自由基反应以及大气物理过程影响下中性PFASs在大气中的衰减。预测了从选定源区经过长距离传输到南海大气中的8:2 FTOH、6:2 FTOH和MeFBSE的浓度，并与观测浓度进行了比较。结果表明，与羟基自由基的反应可能在长距离传输过程中PFAS的大气衰减中起重要作用，特别是对于寿命较短的物质。此外，大气物理过程对PFAS衰减的影响应进一步考虑。（C）2016爱思唯尔有限公司。保留所有权利。