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Taiwan's rivers dry during the winter, exposing large areas of river bed and leading to airborne aeolian river dust. This study used PM10 and windspeed data taken from monitoring stations local to the Zhuoshui River (the river with the largest exposed area in Taiwan) to investigate the relationship between airborne river dust and air quality, and subsequently to estimate river dust emissions. During river dust events, PM10 concentrations were significantly and positively correlated with wind speeds exceeding 5 m/s (the critical wind speed). FPG Lunbei station, located downwind (south of the river) and the closest station to the river, recorded an average hourly PM10 concentration of 189 ± 193 μg/m3 an average correlation coefficient (r) of 0.94 between hourly PM10 concentration and average hourly wind speed, an average annual dust occurrence rate of 15%, and a maximum PM10 concentration exceeding 1000 μg/m3. PM2.5 increased with PM10, albeit at a disproportional rate. When hourly PM10 concentration exceeded 200 μg/m3, most of the particulates in the dust were coarse particulates (PM2.5–10). An hourly PM2.5/PM10 ratio of

Two portable, battery powered particle size distribution analyzers, TSI NanoScan scanning mobility particle sizer (TSI NanoScan SMPS 3910, USA) and Kanomax Portable Aerosol Mobility Spectrometer (Kanomax PAMS 3300, Japan), have been recently introduced to the market. Both are compact and allow researchers to rapidly measure and monitor ambient or indoor ultrafine and nanoparticles in real time. In addition, both instruments apply the SMPS measuring scheme, utilizing a corona charger in place of a radioactive neutralizer, and are integrated with a hand-held condensation particle counter (CPC). In this study, the different designs, flow schemes, and operational settings of both instruments have been summarized based on the information released by the manufacturers and the available published literature. The performance characteristics and monitoring capability of these two portable ultrafine to nanoparticle sizers were investigated and compared to a reference TSI 3936 lab-based SMPS under identical conditions. Reasonable agreement was found between the three instruments in terms of their efficiency in sizing and counting polydispersed particles. Of the two portable analyzers, PAMS was able to provide a higher sizing resolution for monodispersed particle measurements than NanoScan, when operated under the High Mode (higher sheath to aerosol flow ratio).

Decabromodiphenyl ether (DBDE), which has been identified as an endocrine disrupting compound, is used as brominated flame retardant, and this can result in serious bioaccumulation within ecological systems. The objective of this study was to explore DBDE bioremediation (25 mg/kg) using laboratory scale soil slurry microcosms. It was found that effective biodegradation of DBDE occurred in all microcosms. Various biometabolites were identified, namely polybrominated diphenyl ethers congeners and hydroxylated brominated diphenyl ether. Reductive debrominated products such as tri-BDE to hepta-BDE congeners were also detected, and their total concentrations ranged from 77.83 to 91.07 ng/g. The mechanism of DBDE biodegradation in soil slurry microcosms is proposed to consist of a series of biological reactions involving hydroxylation and debromination. Catechol 2,3-oxygenase genes, which are able to bring about meta-cleavage at specific unbrominated locations in carbon backbones, were identified as present during the DBDE biodegradation. No obvious effect on the ecological functional potential based on community-level physiological profiling was observed during DBDE biodegradation, and one major facultative Pseudomonas sp. (99 % similarity) was identified in the various soil slurry microcosms. These findings provide an important basis that should help environmental engineers to design future DBDE bioremediation systems that use a practical microcosm system. A bacterial-mixed culture can be selected as part of the bioaugmentation process for in situ DBDE bioremediation. A soil/water microcosm system can be successfully applied to carry out ex situ DBDE bioremediation.

The physical and chemical characterizations of the fugitive particulate emissions from the electric furance steelmaking operations, cement productions, and asphaltic concrete plant were evaluated in this investigation. Kimoto high volume samplers were used for the determinations of total suspended particulate concentrations as well as the particle size distributions were measured by six-stage Anderson high volume cascade impactors. Moreover, the chemical compositions (Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, and Pb) of the fugitive particles smaller than 2.5 μm and in the 2.5–10 μm size range were analyzed by an X-Ray energy spectrometer. For electric furnace steelmaking operations, most of the fugitive particles occurred in the 2.7-3.6 μm size range. In addition, Fe and Cr were found to be in the coarse fraction as well as Mn, Cu, and Zn were the dominant elements in the fine fraction. For the different processes of the cement operations, there were large variances on the mass concentrations and size distributions of the fugitive particles. More than ninety percents of Ca was found to be in 2.5–10 μm size range. In the asphaltic concrete plant, the mass concentrations of the particulate fugitive emissions were much lower than those observed at the other two occupational environments, because of the good performance of the ventilation system. In summary, the chemical compositions (source profile) of the fugitive particle emissions obtained from this investigation could be used as a tracer in the receptor modeling for evaluating the contributions of the fugitive emissions to the total particle emissions from these three industries.