Gas/particle concentrations and partitioning of PCBs in the atmosphere of Korea

Air samples were taken in a rural area of Kyonggi-do of South Korea to investigate gas/particle concentration and partitioning. Gas/particle phase concentrations of polychlorinated biphenyls (PCBs) were measured over 48 h periods from September 2001 to July 2002. The average contribution (%) of gas to particle was about 90%, which suggests that in the atmosphere PCBs predominantly existed in the gas phase. The correlation coefficients (r) between total PCBs and temperature (°C) showed negative correlation for particle phase and positive correlation for gas phase. The contribution (%) of PCB congeners to total PCBs in gas phase increased with decreasing chlorine substitution. The particle contribution (%) of PCB congeners increased for the less volatile congeners, i.e., those with the higher chlorine number. The coefficient of determination (R2) between log (Cparticle/Cgas) and log KOA was 0.86, which implies that heavier PCB congeners exist more in particle phase than gas phase compared to lighter PCBs. Partitioning of PCBs between gas and particle phases correlated well with the sub-cooled liquid vapor pressure (PoL) and the octanol–air partition coefficient (KOA) for all samples, but the coefficient of determination (R2) differed for each season.