To Örebro University

This study presents four years ambient monitoring data of seventeen 2,3,7,8-chlorine substituted poly-chlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), twelve dioxin-like poly-chlorinated biphenyls (dl-PCBs) and sixteen polycyclic aromatic hydrocarbons (PAHs) designed by the US EPA at a background site in central Europe during 2011-2014. The concentrations expressed as toxic equivalents (TEQs) using the WHO2005-scheme for PCDD/Fs (0.2 fg m(-3)-61.1 fg m(-3)) were higher than for dl-PCBs (0.01 fg m(-3)-2.9 fg m(-3)), while the opposite was found in terms of mass concentrations. Sigma PAHs ranged from 0.20 ng m(-3) to 134 ng(-3). The mass concentration profile of PCDD/Fs, dl-PCBs and PAHs was similar throughout the four years. PCDD/Fs and PAHs concentrations were dominated by primary sources peaking in winter, while those of dl-PCBs were controlled by secondary sources characterized by a spring-summer peak. During 2011-2014, no significant decrease in the atmospheric levels of Sigma PCDD/Fs was observed. On the other hand, the concentrations of Sigma dl-PCBs and Sigma PAHs were decreasing, with halving times of 5.7 and 2.7 years, respectively. We estimated that 422 pg m(-2) year pg m(-2) year TEQ PCDD/Fs and 3.48 pg m(-2) year(-1)-15.8 pg m(-2) year(-1) TEQ dl-PCBs were transferred from the air to the ground surfaces via dry particulate deposition during 2011-2014.