Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from the stack flue gases, fly ashes and bottom ashes of various stationary sources were investigated. The mean total PCDD/F I-TEQ concentration of flue gas ranged from 0.00681 to 0.703 ng I-TEQ/Nm 3 . However, the emission factor of PCDD/F from various incinerators was 0.00827 to 3.50 µg I-TEQ/ton, whereas it was 5.36 µg I-TEQ/body for a crematory (CM). In addition, the mean total PCDD/F I-TEQ content in fly ash from an electric arc furnace (EAF) and a secondary aluminium smelter (secondary ALS) were 74.0, and 49.9 ng I-TEQ/kg, respectively, whereas they are 21.3 and 0.494 ng I-TEQ/kg for bottom ash. Meanwhile, the removal efficiency of PCDD/F by bag filters from EAF was -44.4% which is attributed to the "memory effect". The indicatory PCDD/Fs of EAF, and secondary ALS have the same congeners (1,2,3,7,8,9-HxCDF, 2,3,7,8-TeCDF, and 1,2,3,7,8-PeCDF). In addition, CM, joss paper-A (JP-A) and joss paper-B (JP-B) incinerators have similar indicatory PCDD/F (2,3,4,6,7, OCDF, 1,2,3,4,6,7, and OCDD). The high contribution of total PCDD/F is from fly ash (61.1-95.3%) for metallurgical facilities (EAF, secondary ALS), whereas 99.9% contribution of stack flue gas is from JP-A and JP-B. In conclusion, continually monitoring various PCDD/F emission sources is necessary to understand current PCDD/F emission (flue gas, fly/bottom ash) and the related removal efficiency of existing air pollution control devices. Information about both emission factors of PCDD/Fs and indicatory PCDD/F congeners are useful for the establishment of control strategies and for use as fingerprints with regard to the dominant congeners from different emission sources.

The objectives of the present study were to investigate particulate matter (PM) and polycyclic aromatic hydrocarbon (PAH) concentrations in ambient air during rice straw open burning and non-open burning periods. In the ambient air of a rice field, the mean PM concentration during and after an open burning event were 1828 and 102 μg m⁻³, respectively, which demonstrates that during a rice field open burning event, the PM concentration in the ambient air of rice field is over 17 times higher than that of the non-open burning period. During an open burning event, the mean total PAH and total toxic equivalence (BaP(eq)) concentrations in the ambient air of a rice field were 7206 ng m⁻³ and 10.3 ng m⁻³, respectively, whereas after the open burning event, they were 376 ng m⁻³ and 1.50 ng m⁻³, respectively. Open burning thus increases total PAH and total BaP(eq) concentrations by 19-fold and 6.8-fold, respectively. During a rice straw open burning event, in the ambient air of a rice field, the mean dry deposition fluxes of total PAHs and total BaP(eq) were 1222 μg m⁻² day⁻¹ and 4.80 μg m⁻² day⁻¹, respectively, which are approximately 60- and 3-fold higher than those during the non-open burning period, respectively. During the non-open burning period, particle-bound PAHs contributed 79.2-84.2% of total dry deposition fluxes (gas + particle) of total PAHs. However, an open burning event increases the contribution to total PAH dry deposition by particle-bound PAHs by up to 85.9-95.5%. The results show that due to the increased amount of PM in the ambient air resulting from rice straw open burning, particle-bound PAHs contributed more to dry deposition fluxes of total PAHs than they do during non-open burning periods. The results show that biomass (rice straw) open burning is an important PAH emission source that significantly increases both PM and PAH concentration levels and PAH dry deposition in ambient air.

This study selected 21 representative public sites for the survey of indoor air quality in Tainan area, including hospital, school, fitness center, government office, library, theater, transport station, and supermarket. Indoor air quality was first assessed by direct detection apparatus, including CO2, CO, HCHO, TVOCs, bacteria, fungi, PM10, PM2.5, O3 and temperature. Based on the results of walk-through detection, the spatial distribution of indoor air contaminants was further measured in a 24 hour period by the EPA standard method. The detailed measurements illustrated HCHO, O3, PM10 and PM2.5 concentrations are lower than the suggested threshold levels in all public sites. CO2 concentrations at hospitals and school are all exceeding category 1 threshold of 600 ppm. Bacteria exceeding the suggested threshold of 500 CFU/m3 for category 1 and 1000 CFU/m3 for category 2 is popular at most public sites. One fitness center was found exceeding the TVOCs threshold of 3 ppm, and outdoor air can be a potential source. The high levels of CO2 and bacteria were a common indoor air quality problem, and the regulated strategy of crowd control and air conditioning management was required for a healthy indoor environment.

People usually spend almost 90% of time under various indoor surroundings in their daily lives, and thus the impact of indoor air quality (IAQ) on human health has received much attention recently. In this study, 20 public sites were selected as case studies to compare the difference of indoor air quality measurements. Indoor air quality was first assessed by direct detection apparatus, including CO2, CO, HCHO, TVOCs, PM10, PM2.5, and O3. Based on the results of walk-through detection, indoor air contaminants at hot-spot location were measured in a 24 hour period by the EPA standard method. The use of direct detection apparatus has the advantages of easy operation, high mobility, rapid detection, and less cost. However, official data of indoor air quality measurement is based on the detailed measurement by Taiwan EPA’s standard methods that possess high precision and accuracy. The comparison of direct detection data and the detailed measurements by standard methods illustrated that there exists a high linear relationship for CO2, PM10 and PM2.5 measurements. It means that direct detection data of CO2, PM10 and PM2.5 are reliable, and direct detection apparatus can be applied to monitoring of these indoor air contaminants for the better control of their accumulations.