Gas-particle partitioning of PCDD/Fs in Nagoya urban air, Japan

Polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) in the atmosphere were sampled by a high-volume filter/sorbent air sampler at an urban (Nagoya, Japan) site from May 2000 to January 2001 under the average ambient temperatures ranging from 1 degrees C to 33 degrees C. The gas and particle phase concentrations of PCDD/Fs were measured and then the field gas-particle partitioning data were used to assess the Junge-Pankow adsorption model and the K(OA) absorption model. For both PCDDs and PCDFs, passable agreement was obtained between the measured and predicted particulate-band fraction (phi) values by the Junge-Pankow model, but the model tends to overpredict phi for all individual Cl4-8DD/F congeners, especially for the lower chlorinated congeners. On the other hand, good agreement was obtained between the measured and predicted log K(p) values by the K(OA) model for both PCDDs and PCDFs. However, the K(OA) absorption model did not fit the field data at low ambient temperature below 5 degrees C. The disagreement at low ambient temperatures was estimated to arise from the gas adsorption artifacts during the sampling. From the validation by the field measurement data in Nagoya urban air, it is found that the K(OA) absorption model is capable of predicting more accurately gas-particle partitioning of PCDD/Fs than the Junge-Pankow adsorption model.