Concentrations and gas-particle partitioning of PCDD/Fs in the urban air of Dalian,China

PCDD/Fs in the urban air of Dalian,China were monitored with high-volume active sampler from November 2009 to October 2010.The concentration of Cl 4-8 DD/Fs ranged from 3065 to 49538 fg m-3,with an average of 10249 fg m-3.The international toxic equivalents(I-TEQ) value of that was 61.8 1182 fg m-3,with an average of 235 fg m-3,which was comparable to those in the other urban locations around the world.It was found that the Cl 4 8 DD/Fs appeared to be present mainly in the particle phase during winter,spring and autumn,while during summer which were dominantly in gas phase.The ratio of Cl 4-8 DD/Fs present in particle phase increased with the increasing level of chlorination.The concentrations of PCDFs and PCDDs decreased with the increase of chlorinated level,while the concentrations of 2,3,7,8-PCDDs congeners increased with the increase of chlorination level.The homolog profiles of the concentrations of PCDFs presented were higher than those of the PCDDs,which indicated the PCDD/Fs pollution source of the air in Dalian was characteristic for thermal source pollution.The correlation analysis of meteorological parameters with the concentrations of Cl 4-8 CDD/Fs was conducted using SPSS packages,and it was found that the ambient temperature and atmospheric pressure were important factors influence the concentration of PCDD/Fs in the air.The respiratory risk and intake dioxins of the residents around the sampling sites were studied in the paper.It was found that Junge-Pankow model was much more accurate in predicting the gas-particle partitioning behavior of PCDD/Fs homologues during winter,while the Harner-Bidleman model shows better agreement with the measured data during winter and summer.