A comparison of the levels and particle size distribution of lower chlorinated dioxin/furans (mono- to tri-chlorinated homologues) with those of tetra- to octa-chlorinated homologues in atmospheric samples

摘要

There is very little information on the levels and particle size distributions of lower chlorinated dibenzop-dioxins and dibenzofurans (mono- to tri-CDD/Fs, Sigma Cl1-3DD/Fs) in the atmosphere, while a number of studies have examined tetra- to octa-chlorinated homologues (Sigma Cl4-8DD/Fs). In this study, we measured the concentration and particle size distribution of Sigma Cl1-3DD/Fs in ambient air in suburban Beijing and compared them with that of Sigma Cl4-8DD/Fs for the first time. The mean concentration of Sigma Cl1-3DD/Fs was 54.63 pg m(-3), which is about 5.4 times that of Sigma Cl4-8DD/Fs. The Sigma Cl1-3DD/Fs accounted for 85% of Sigma Cl1-8DD/Fs, and MoCDFs made up the largest proportion (43%) of PCDD/F homologues. The Sigma Cl1-3DD/Fs mainly occurred in the gas phase, while the Sigma Cl4-8DD/Fs mainly occurred in the particulate phase. The majority of Sigma Cl1-3DD/Fs (70%) occurred in d(ae) > 1.0 mu m particles, which is the reverse of the trend observed for Sigma Cl4-8DD/Fs, of which 78% occurred in d(ae) < 1.0 mu m particles. The observed high concentrations of Sigma Cl1-3DD/Fs and different distribution patterns demonstrate that it is necessary to consider the lower chlorinated homologues to improve our understanding of the environmental behavior and health risk assessments of PCDD/Fs in the atmosphere. (C) 2016 Elsevier Ltd. All rights reserved.