The ambient air in vicinity of different industrial sources for PCDD/PCDFs was sampled by TSP/PM10 active samplers and
passive PUF disk samplers in Tangshan City, a metropolis containing clusters of various industrial plants. The TEQ concentrations
of PCDD/PCDFs ranged from 44.2 to 394.1 fg I-TEQ/m3 with an average of 169.9 fg I-TEQ/m3. 2,3,4,7,8-PeCDF was the dominant
contributor to PTEQ, contributing 41% (12% to 55%), while 1,2,3,4,6,7,8-HpCDF, OCDD and OCDF were the major congeners for
the total concentrations. The ratios of PPCDF/PPCDD reached 2.54 on average, suggesting that de novo synthesis in thermal processes
played an important role to the airborne pollution of PCDD/PCDFs. The similarities congener profiles indicated that TSP and PM10
active sampling methods are comparable for the determination of the PCDD/PCDFs in ambient air, and the ratios of concentrations
determined by the two methods suggested that the PCDD/PCDFs tended to stay in fine particles. It was found that 2,3,7,8-TCDF and
OCDD were the dominating congeners in the passive PUF disks samples. Through principal components analysis, the coke industry
was suggested to be a relatively high potential emission source for PCDD/PCDFs in the ambient air of Tangshan, which was possibly
formed by de novo synthesis mechanism. In this study, the atmospheric impacts to the environment from di erent industrial sources
could be ranked as follows (from high to low): coking, iron sintering, steel making, power generation and chlorinate alkali chemical
production industries.
