Atmospheric Pollution Profiles, Gas-particle Partitioning Of Polychlorinated Dibenzo-p-dioxins And Dibenzo-furans (PCDD/Fs) And Polychlorinated Biphenyls (PCBs) In Beijing

Dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) whose ubiquitous presence in ambient environment is of recognized health concern. Air samples were collected in four seasons in 2008 in Beijing. The studies on PCDD/Fs and PCBs showed seasonal mean levels of PCDD/Fs and PCBs were respectively in the rang of 1.5～3.7 pg/m3 and 1.1～14 pg/m3 with a toxic equivalents in the rang of 78～270.9 fgI-TEQ/m3 and 1.6～15.4 fgWHO-TEQ/m3 respectively in PM10, and seasonal mean levels of PCDD/Fs and PCBs were respectively in the rang of 1.1～3.2 pg/m3 and 0.8～10 pg/m3 with a toxic equivalents in the rang of 51.6～233.2 fgI-TEQ/m3 and 1.0～13.8 fgWHO-TEQ/m3 respectively in PM2.5. The concentrations of PCDD/Fs and PCBs in PM10 and PM2.5 show evident seasonality, the concentrations in winter and spring were much higher than in summer and autumn. The concentrations of individual congeners followed the same spatial change trends in same season. The higheast concentrations were found in industrial area and the lowest concentration were found in background.The results of studies on gas-particle partitioning of PCDD/Fs and PCBs indicated PCBs (97.5%) were primarily in gas and PCDD/Fs (92.1%) were primarily bounded in particle. logKp and logPL0 of PCDD/Fs and PCBs presented obvious linear relativity.PCDD/Fs and PCBs levels were notablely lower during traffic limit event than no traffic limit event, contributions of PCDD/Fs and PCBs during traffic limit event to those during no traffic limit event were 25.9% and 30.39% respectively in TSP, and 23.67% and 38.37% respectively in PM10, and 13.97% and 42.6% repectively in PM2.5.17 2,3,7,8-PCDD/Fs and 19PCBs were detected in cooking smoke particle PM10 and PM2.5. PCBs concentration of PM10 and PM2.5 were 16 pg/m3 and 13 pg/m3 respectively, and PCDD/Fs concentration of PM10 and PM2.5 were 3 pg/m3 and 2pg/m3 respectively.PCDD/Fs and PCBs levels and TEQ in fly ash from 5 different industrial incinerators were markedly different. The highest PCDD/Fs and PCBs levels( respectively 442.4 pg/g and 796.4 pg/g ) and TEQ ( respectively 74264 fgI-TEQ/g and 2582 fgWHO-TEQ/g) were detected in fly ash of solid waste incinerator, that were dominant the contributions contributors in ambient environment. In comparation, the contributions of PCDD/Fs and PCBs ( respectively 1441 fgI-TEQ /g and 34.08 fgWHO-TEQ/g ) to environmental PCDD/Fs and PCBs pollution in fly ash 3 that employ sulfuration bed as incinerator and employ active carbon as sorbent were lower.