Distribution Characteristics Study On Dioxin-like Compounds In The Atmosphere Of Typical Areas

Polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinated dibenzofurans（PCDFs）, polychlorinated biphenyls （PCBs） and polybrominated diphenyl ethers（PBDEs） are four groups of persistent organic pollutants （POPs） that are ubiquitousin the environment, and refractory, easy to accumulate in the fatty tissue of livingorganisms, of high toxicity even though at very low levels. This research focuses onthe levels and distributions of the three dioxin-like compounds in the atmosphere oftypical areas by using isotope dilution/high resolution gas chromatography/highresolution mass spectrometry method, which is from the three following aspects:Levels and distributions of PCDD/Fs and PCBs in Beijing atmosphere in during theperiod of2010to2011were studied using passive air samplers. The averageconcentration of ΣPCDD/Fs in Beijing are1.712pg m^-3（summer-autumn） and0.497pg m^-3（winter-spring）, while the PCBs are57.23pg m^-3（summer-autumn） and28.89pg m^-3（winter-spring）. Comparing with the results of high volume active samplers,PUF passive air samplers are feasible to be used for supplement of high volume activesamplers. By analyzing the uptake dynamic theory of PUF passive air sampler, lowsubstituted congers are found to reach the equilibrium of uptake process after100days’ sampling, but not for high substituted congers.At the same time, the levels and distributions of PCDD/Fs and PCBs in theambient air of7districts in Beijing were studied by using PUF passive air samplersfrom December2010to December2011. The average concentrations of∑₁₇PCDD/Fsis low comparing with other studies, which was0.343pg m^-3(0.208⁰.607pg m^-3).The peak of the concentrations appeared in the summer, which was0.904pg m^-3,while the concentrations of∑₁₉PCBs varies from11.77to122.8pg m^-3(averaged as39.63pg m^-3). The two categories of compounds demonstrate distinct seasonalvariation, which means the concentrations are easy to be influenced as the fluctuationof temperatures. Nevertheless, there would be substantial connection between theconcentrations of the two categories of compounds and local sources.Finally, the levels and distributions of PCBs and PBDEs in the atmosphere of Antarctic King George Island were also investigated using PUF passive air samplingtechniques. Based on HRGC/HRMS analysis, both PCBs and PBDEs were detected indifferent levels. The air concentrations of∑₆PCBs were30pg m^-3(8.4to47pg m^-3)and the∑PBDEs levels were9.5pg m^-3(4.0to14pg m^-3). Compared with otherpublished literatures, the levels of PCBs and PBDEs in this study were within globalbackground criteria. Lighter PCBs and PBDEs were dominating congeners, reflectingpossible sources associated with global long-range atmospheric transport.