The concentration of polybrominated diphenyl ethers (PBDEs) in the ambient air of two municipal solid waste incinerators (MSWIs) and one coal-fired power plant (TPP) were determined. Along with the sites mentioned above, eight ambient air samples were collected. Cluster analysis was carried out to determine the relationship of PBDE characteristics between each site. Finally, PBDE dispersion modeling in the atmosphere was applied by using ISCST3 (Industrial Source Complex Short Term 3) to assess the impact of the above two municipal solid waste incinerators and one coal-fired power plant on the ambient air. The total-PBDE concentrations in the ambient air were between 24.9 and 139 pg/Nm3, averaging 59.8 pg/Nm3 (n = 16). The BDE-209, BDE-47 and BDE-207 were the most predominant three among all 30 PBDE congeners, which contributed more than 58%, 9%, and 4% of total-PBDE mass to the ambient air, respectively. The results of cluster analysis indicated that no direct correlations existed among the emission sources (MSWI-A, MSWI-B, TPP) and the receptors (sampling sites). From the results of dispersion modeling, the annual total PBDE concentration in ambient air contributed by the MSWI-A, MSWI-B, TPP together were found to be 0.0259% ± 0.0208%. Hence, the results of both cluster analysis and dispersion modeling showed that MWSI-A, MSWI-B, and TPP were definitely not the major contributors of PBDEs to the ambient air environment. The ashes collected from the air pollution control devices of both the MSWIs and the TPP are probably a more important environmental issue and therefore should be paid more attention to.