PCDD/PCDF in the ambient air of a metropolitan area in the U.S.

Abstract The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in the ambient air at several sites in metropolitan Dayton, Ohio have been determined. Total PCDD in the tetra- through octachlorinated groups which were detected in industrialized regions in the present study ranged from 1.6 to 11.2 pg/m 3 , whereas the corresponding total PCDF ranged from 0.62 to 11.7 pg/m 3 . No PCDD/PCDF were found in rural regions, typical average detection limits being on the order of 0.02 – 0.17 pg/m 3 . PCDD/PCDF in the industrialized regions appear to originate from a combination of sources, including municipal solid waste incinerators, motorized vehicles, and a PVC-coated metal incinerator, the latter being a major source of these pollutants. Total PCDD/PCDF congener group patterns, as well as discrete isomer patterns for the various chlorinated groups, in the samples collected at the several sites, were compared. Approximately 50% of the total chlorinated congeners of PCDD/PCDF in the ambient air samples collected consist of 2,3,7,8-chlorine substituted isomers.