The mean concentrations of PCDD/Fs in ambient air, leaf and soil in the vicinity of Beitou incinerator are 0.0347 pg I-TEQ/Nm3, 1.50 ng I-TEQ/kg and 2.42 ng I-TEQ/kg, respectively. The mean concentrations of PCDD/Fs in ambient air, leaf and soil in the vicinity of Neihu incinerator are 0.0227 pg I-TEQ/Nm3, 0.970 ng I-TEQ/kg and 3.08 ng I-TEQ/kg, respectively. The mean concentrations of PCDD/Fs in ambient air, leaf and soil in the vicinity of Muzha incinerator are 0.0212 pg I-TEQ/Nm3, 0.656 ng I-TEQ/kg and 1.47 ng I-TEQ/kg, respectively. In addition, whole blood samples taken from chickens from Beitou, Neihu and Muzha incinerators were investigated. The dioxin content of chicken blood from Beitou, Neihu and Muzha incinerators are 1.91, 1.45 and 1.39 pg WHO-TEQ g-l.w.(lipid) -1, respectively. Based on the PCDD/F concentrations of the three matrices determined at sites upwind and downwind, it was found that the environmental impact of the investigated incinerators were not obvious. PCDD/F concentration isopleths of the three environmental compartments coupled with wind rose of the region proved that the influence of the three investigated incinerators on the environment was also rather limited. Consequently, we can conclude that the PCDD/F emission from the incinerators in Taipei city do not have significant impact on the ambient atmosphere. Comparing the PCDD/F I-TEQ concentrations in the ambient air of the selected incinerators in this study with various areas in Taiwan, we found that the investigated PCDD/F level in ambient air has the lowest PCDD/F I-TEQ concentration. The above results for associated toxicity were significantly lower than 0.6 pg I-TEQ/Nm3, which was the dioxin emission standard in Japan. In addition, the average dioxin contents of vegetation and soil in three investigated incinerators are similar to those published previously.