| Title: | Slopes and intercepts from log-log correlations of gas/particle quotient and octanol-air partition coefficient (vapor-pressure) for semi-volatile organic compounds: I. Theoretical analysis |
| Author(s): | Li YF; Qiao LN; Macdonald RW; |
| Address: | "International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment/ School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, PR China; IJRC-PTS, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, PR China; IJRC-PTS-NA, Toronto, Ontario, M2N 6X9, Canada. Electronic address: dr_li_yifan@163.com. International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment/ School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, PR China; Department of Marine Sciences, Marine College, Shandong University, Weihai, 264209, China. Institute of Ocean Sciences, Department of Fisheries and Oceans, P.O. Box 6000, Sidney, BC, V8L 4B2, Canada" |
| DOI: | 10.1016/j.chemosphere.2020.128865 |
| ISSN/ISBN: | 1879-1298 (Electronic) 0045-6535 (Linking) |
| Abstract: | "Gas/particle partitioning governs the transport and fate of semi-volatile organic compounds (SVOCs) released to the atmosphere. The partition quotient of SVOCs, K(P), is related to their subcooled liquid vapor pressure (logK(P) = m(p) logP(L) + b(p)) and to their octanol-air partition coefficient (logK(P) = m(o) logK(OA) + b(o)). Previous theory predicts that -m(p) and m(o) should be close to, or equal to 1 based on the assumption that gas- and particle-phases are at equilibrium in the atmosphere. Here, we develop analytical equations to calculate m(o) and b(o) as functions of logK(OA) and m(p) and b(p) as functions of logP(L). We find that experimental, analytical, or statistical artifacts and other reported factors are not the leading causes for deviations of the slopes, m(p) and m(o), from -1 and 1, respectively. Rather, it is the inherent parameter, K(OA), that determines m(o) and b(o), and equivalently, P(L) is the major parameter determining m(p) and b(p), and such deviations are evidence that equilibrium is an inappropriate assumption. In contrast, the actual steady-state between gas and particle phases of SVOCs leads that their -m(p) and m(o) should range from 0 to 1, implying that equilibrium is a reasonable assumption only when -m(p) and m(o) are larger than 0.49. To illustrate these points, we provide a detailed discussion of the global atmospheric transport of polybrominated diphenyl ethers (PBDEs) with emphasis on Polar Regions where low air temperatures favor a special steady-state, where their slopes m(p) and m(o) can reach 0, indicating a constant value of logK(P) (-1.53)" |
| Keywords: | *Air Pollutants/analysis Atmosphere Environmental Monitoring Octanols Vapor Pressure *Volatile Organic Compounds/analysis Equilibrium Gas/particle partitioning Polar regions SVOCs Slopes Steady state; |
| Notes: | "MedlineLi, Yi-Fan Qiao, Li-Na Macdonald, Robie W eng England 2020/11/22 Chemosphere. 2021 Jun; 273:128865. doi: 10.1016/j.chemosphere.2020.128865. Epub 2020 Nov 9" |
