Prediction of gas/particle partitioning of polybrominated diphenyl ethers (PBDEs) in global air: A theoretical study
Prediction of gas/particle partitioning of polybrominated diphenyl ethers (PBDEs) in global air: A theoretical study
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全球空气中多溴二苯醚 (PBDE) 的气体/颗粒分配预测：理论研究
DOI：
10.5194/acp-15-1669-2015
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发表时间：
2015-01-01
影响因子：
6.3
通讯作者：
Yang, M.
中科院分区：
文献类型：
--
作者：
Li, Y. -F.;Ma, W. -L.;Yang, M.
摘要。半挥发性有机化合物（SVOCs）的气体/颗粒（G/P）分配是一个重要的过程，主要决定了它们在大气中的命运、远距离的大气输送以及进入人体的途径。以往关于这一问题的所有研究都是基于平衡条件的假设，其结果在大多数情况下不能很好地预测监测研究的结果。在这项研究中,稳态模型而非平衡态模型的调查G / P分区的行为多溴二苯醚(多溴二苯醚)成立,和一个方程计算分区系数下稳态(KPS)的多溴二苯醚(日志KPS =日志KPE +日志α)开发的一个平衡的术语(日志KPE =日志高雅+ logfOM−11.91 fOM是粒子的有机质含量)和非平衡项(日志α,由颗粒的干湿沉积引起)，两者都是对数KOA（辛醇-空气分配系数）的函数。结果表明，当非平衡项为零时，平衡是稳态的一种特殊情况。利用对数KOA的两个阈值，即对数KOA1和对数KOA2，建立了多溴二苯醚平衡和非平衡状态的分类准则，将对数KOA的范围划分为平衡、非平衡和最大分区三个域。据此，确定了温度t的两个阈值tTH1，即log KOA = log KOA1时的tTH1和log KOA = log KOA2时的tTH2，这两个阈值也将每个PBDE同系物的温度范围划分为相同的三个域。我们预测当log KOA≥log KOA2或t≤tTH2时，每个PBDE同系物都能达到最大分割域（log KPS值达到最大常数- 1.53）。本研究建立的新方程用于预测中国持久性有机污染物（POPs）土壤和空气监测计划，第二阶段（中国- samp - ii）计划以及全球其他监测计划（包括亚洲，欧洲，北美和北极）中多溴二苯醚的G/P分配系数，结果与所有监测数据吻合良好，除了在电子垃圾站点获得的数据，因为这些站点的多溴二苯醚排放不可预测。这项研究提供了证据，证明新开发的基于稳态的方程优于几十年来用于描述G/P分配行为的基于平衡态的方程。我们建议对多溴二苯醚的G/P分配行为的研究应基于非稳态，而不是平衡态，平衡态只是稳态的一种特殊情况，非平衡因素可以忽略。我们还认为，我们的新方程为环境科学家在多溴二苯醚的G/P分配监测和建模研究中提供了有用的工具，并且可以扩展到预测其他SVOCs的G/P分配行为。
Abstract. Gas/particle (G/P) partitioning of semi-volatile organic compounds (SVOCs) is an important process that primarily governs their atmospheric fate, long-range atmospheric transport, and their routes of entering the human body. All previous studies on this issue are hypothetically based on equilibrium conditions, the results of which do not predict results from monitoring studies well in most cases. In this study, a steady-state model instead of an equilibrium-state model for the investigation of the G/P partitioning behavior of polybrominated diphenyl ethers (PBDEs) was established, and an equation for calculating the partition coefficients under steady state (KPS) of PBDEs (log KPS = log KPE + logα) was developed in which an equilibrium term (log KPE = log KOA + logfOM −11.91 where fOM is organic matter content of the particles) and a non-equilibrium term (log α, caused by dry and wet depositions of particles), both being functions of log KOA (octanol–air partition coefficient), are included. It was found that the equilibrium is a special case of steady state when the non-equilibrium term equals zero. A criterion to classify the equilibrium and non-equilibrium status of PBDEs was also established using two threshold values of log KOA, log KOA1, and log KOA2, which divide the range of log KOA into three domains: equilibrium, non-equilibrium, and maximum partition domain. Accordingly, two threshold values of temperature t, tTH1 when log KOA = log KOA1 and tTH2 when log KOA = log KOA2, were identified, which divide the range of temperature also into the same three domains for each PBDE congener. We predicted the existence of the maximum partition domain (the values of log KPS reach a maximum constant of −1.53) that every PBDE congener can reach when log KOA ≥ log KOA2, or t ≤ tTH2. The novel equation developed in this study was applied to predict the G/P partition coefficients of PBDEs for our Chinese persistent organic pollutants (POPs) Soil and Air Monitoring Program, Phase 2 (China-SAMP-II) program and other monitoring programs worldwide, including in Asia, Europe, North America, and the Arctic, and the results matched well with all the monitoring data, except those obtained at e-waste sites due to the unpredictable PBDE emissions at these sites. This study provided evidence that the newly developed steady-state-based equation is superior to the equilibrium-state-based equation that has been used in describing the G/P partitioning behavior over decades. We suggest that the investigation on G/P partitioning behavior for PBDEs should be based onsteady-state, not equilibrium state, and equilibrium is just a special case of steady-state when non-equilibrium factors can be ignored. We also believe that our new equation provides a useful tool for environmental scientists in both monitoring and modeling research on G/P partitioning of PBDEs and can be extended to predict G/P partitioning behavior for other SVOCs as well.