Atmospheric concentration characteristics and gas–particle partitioning of PCBs in a rural area of eastern Germany

Atmospheric concentrations of polychlorinated biphenyls (PCBs) were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany. The average total concentration of PCBs was 110 ± 80 pg m−3 and they were predominately present in the gas phase (∼95%). Composition of individual congeners closely resembled those of Clophen A30 and Aroclor 1232. Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius–Clapeyron plots (−4500 to −8000) indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Particle–gas partitioning coefficients (KP) of PCBs were well correlated with the respective sub-cooled vapor pressures (PLo), but the slopes obtained from log KP versus logPLo plots (−0.16 to −0.59) deviated significantly from the expected value of −1. Overall, gas–particle partitioning of PCBs was better simulated by Junge–Pankow than octanol/air partition coefficient-based model.