Polychlorinated biphenyls associated with fine particles (PM25) in the urban environment of Chile: concentration levels, and sampling volatilization losses.

Polychlorinated biphenyls (PCBs) were measured in fine particles (PM25, particles smaller than 2.5 microm in diameter) collected in two urban areas of Chile, Santiago and Temuco, during August and October 1998. A diffusion denuder sampling system was used for the collection of 19 samples. The concentrations of total PCBs (47 congeners) ranged from 672 to 1,790 pg/m3 in the city of Temuco and from 1,159 to 2,750 pg/m3 in Santiago. These concentrations are moderately higher than those observed in other urban areas around the world. High amounts of PCBs may volatilize from fine particles during aerosols sampling using conventional high-volume samplers. Average volatilization losses, determined by the diffusion denuder system, varied between 54 and 97%, showing a strong dependence on partial pressure of individual PCB congeners and air temperature. Overall, our results suggest that measurements of PCBs in the particulate phase of the atmosphere, by using conventional high-volume samplers, might be significantly underestimated because of volatilization losses. The underestimation of PCB and other toxic semivolatile organic compound (SOC) levels associated with fine particles in the urban environment may have consequences to the estimation of health risk posed by inhalation.