The emission and distribution of polychlorinated debenzo-p-dioxins/dibenzofurans (PCDD/Fs) was investigated in two municipal solid waste incinerators (MSWIs) and one coal-fired power plant (PP) in southern Taiwan. Samples were collected from stack flue gases (SFG), bottom residues (BR), super heater (SH), economizer (EC), semi-dry absorber (SDA), bag filter (BF), and fly ash pit (FAP) in MSWIs. Stack flue gases, bottom residues and electrostatic dust collectors (ESD) in PP were also collected. In order to compare the difference between the results of MSWIs and PP, samples from SFG, BS, and FAP in a PP were also determined. Seventeen congeners of PCDD/Fs were analyzed by utilizing a highresolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS). Distributions of total PCDD/F-I-TEQ in each unit of MSWI-A and MSWI-B were SFG (0.3%, 0.07%), BR (3.9%, 0.62%), SH (0.17%, 0.24%), EC (4.2%, 0.05%), SDA (1.29%, 7.06%), and BF (90.14%, 91.97%), respectively. However, those in SFG, BS, and FAP of PP were 99.58%, 0.17%, and 0.25%, respectively. The above results indicated 99.5% PCDD/Fs were trapped in the fly ash of MWSI. On the other hand, 99.7% PCDD/Fs was emitted to the atmosphere from PP. The results of this study provide useful information for controlling PCDD/Fs in MSWIs and PP.

In this study, the distributions of polybrominated dibenzo-p-dioxins (PBDD/Fs) and dibenzofurans and polybrominated diphenyl ethers (PBDEs) in the bottom residues of the combustion chambers (BR), the fly ashes from superheaters (SH), economizers (EC), semi-dry scrubbers (SDA), fabric filters (BF), fly-ash pits (FAP) and stack flue gases (SFG) of two municipal solid waste incinerators (MSWIs) and the bottom residue (BR), electrostatic dust precipitators (ESD), and stack flue gases (SFG) of a coal-fired power plant (TPP) were investigated. BR of combustion chambers exhibited the highest content of PBDEs and PBDD/Fs among all the units. The amount of PBDE mass found in bottom residues constituted 99.7% at MWSI-A, and 92.6% at MSWI-B and 75.1% at TPP of the total PBDE discharges, respectively; while the second highest PBDE mass observed in MSWI-A and MSWI-B was from SFG (0.146%) and EC (5.54%), respectively. In TPP, the PBDE distribution was 75.1% in BR, 12.5% in ESD, and 12.4% in SFG. The mean concentrations of PBDEs emitted from SFG of MSWI-A, and MSWI-B were 9.32 ng/Nm 3 , and 7.62 ng/Nm 3 , respectively; however, that of PBDE discharged from SFG of TPP was only 5.43 ng/Nm 3 . The dominant congener found from MSWI-A,MSWI-B and TPP, was BDE-209, accounting for 65.9%, 77.7%, and 77.6% of total PBDE concentrations in SFG, respectively; whereas BDE-206 (6.01%-6.36%) was the second highest congener. Meanwhile, the PBDE emission factors from the stack flue gases were 35.6 ± 10.9 μg/ton-waste at MWSI-A, 47.6 ± 29.4 μg/ton-waste at MSWI-B and 62.9 ± 10.9 μg/ton-coal at TPP of the total PBDEs, respectively; showing the PBDE emission rates and contributions of TPP to the ambient air are actually much higher than those of MSWIs, while the PBDE concentrations in SFG of TPP were lower than MSWIs'. Further investigations on the safety of BR reutilization and the impact of SFG from TPP are strongly advised.

This study investigated Hg emissions from a coal-fired power plant (CFPP) and their impact on the nearby environment. Atmospheric Hg concentrations were measured at sampling sites near a CFPP located in central Taiwan from November 2008 to March 2011. The mean gaseous and particulate Hg concentrations were 2.59-4.12 ng/m 3 and 105-182 pg/m 3 , respectively, with gaseous Hg predominant at all sites (approximately 96% of the total atmospheric Hg). The seasonal variations of both gaseous and particle Hg concentrations in the atmosphere showed a similar pattern, with the highest concentrations in the cold season and the lowest in warm season. The mean emission factor of 13.1 mg/ton was found for the CFPP burning bituminous coal, with an electrostatic precipitator (ESP), flue gas desulfurization (FGD), and selective catalytic reduction (SCR) in series as air pollution control devices (APCDs). This figure was significantly lower than that measured at various power facilities, probably due to different fuel type, APCDs configuration, and flue gas condition. The modeling of the Industrial Source Complex Short Term (ISCST) revealed that the contribution of the CFPP to ambient atmospheric Hg was minimal (less than 1%).

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/Nm 3 , averaging 59.8 pg/Nm 3 (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.