Spatial distribution of airborne polychlorinated biphenyls in Cleveland, Ohio and Chicago, Illinois.

Passive samplers were deployed across Cleveland, OH and Chicago, IL to evaluate the spatial variability of airborne PCBs in urban areas. We measured SigmaPCB concentrations, the sum of 151 congeners or congener groups quantified using tandem mass spectrometry, spatial distributions, and congener profiles in two urban areas in the Great Lakes region. Mean SigmaPCB concentrations were significantly different between Cleveland (1.73 +/- 1.16 ng m(-3)) and Chicago (1.13 +/- 0.58 ng m(-3)) during the August 2008 sampling period. Mean congener profiles were compared with commercial Aroclor mixtures and found to be similar to Aroclor 1242 in Cleveland and similar to a mixture of 1242 and 1254 in Chicago. We observed large spatial variation in concentrations and weak or no significant autocorrelation between sites in both cities. "Hot spots" of high SigmaPCB concentrations were identified in both urban areas and the congener profiles at these locations were most strongly correlated to that of PCB Aroclor mixtures. Congener profiles showed important differences including the enrichment of dioxin-like congeners in Chicago.