Behavior and source characteristic of PCBS in urban ambient air of Yokohama, Japan

To understand the behavior and sources of polychlorinated biphenyls (PCBs) in ambient air, gaseous and particulate phase concentrations were measured at Yokohama City, Japan, during March 2002 and February 2003. The concentration of total PCB and TEQ ranged from 62 to 250 pg/m3 and from 2 to 14 fgTEQ/m3, respectively. The gas-particle partition coefficient (Kp) was obtained as a function of temperature. The relationship between the partition coefficient and the sub-cooled liquid vapor pressure (PL) was also established (coefficients of determination for log Kp versus log PL plot were >0.76, except for three samples). As a result, the partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. Principal component analysis (PCA) was applied to the source identification of PCBs in ambient air. The concentrations of 122 congeners between tetra-CBs and deca-CB were used as input variables, and three PCs with eigenvalue more than 10 were obtained. The principal component 1 (PC 1) accounted for 43.4% of the total variance, and was interpreted as volatilization from PCB products and/or sites polluted by PCBs. The concentrations of PCB congeners were strongly related with PC 1 which showed high correlation with temperature. PC 2 accounted for 22.3%, and was interpreted as PCBs from incineration sources, while PC 3 accounted for 10.8%, but could not be interpreted. The relationship between the gas-particle partition coefficient (Kp) and sub-cooled liquid vapor pressure was estimated using gaseous and particle phase concentration in ambient air, and was estimated source apportionment of PCBs.