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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.

Given the low cost of their components and their demonstrated reliable efficiencies, dye-sensitized techniques based on the titanium dioxide (TiO2) thin films have received much research attention in the past decade. The dSubscript textye/TiO2 thin films were prepared on glass fibers substrate by a dip-coating method combined with a sol-gel process and the photocatalytic of acetone was investigated in this study. The natural botanical dye of Gardenia jasminoides with absorption reflection intensity in 410-460 nm of liquid extraction was used to improve the photo absorbability under illumination of visible light source. Degradation of acetone under 420 nm light illumination was conducted to evaluate the photocatalytic ability of the dye/TiO2 thin films. The SEM images evidence that fibers existed in the dye/nano-TiO2 composites. The dye/TiO2 thin films catalyst prepared in the laboratory shoSubscript textwed photocatalytic performance with the degradation efficiency of 55% under 420 nm. A few percentages increase in removal efficiency when compared with the dye less TiO2 thin films.

Stainless steel (SS) 304 sieves are characterized by their high permeability and high surface area, which can be flexibly used in different photochemical reactor designs. In this work, low pressure plasma cleaning methods in Ar or N2 atmospheres were adopted to clean the surfaces of sieves prior to the deposition of TiO2 coatings by sol–gel and dipping methods. Heat treating at 200 °C was employed after the deposition process. The surface morphologies, crystalline structures and chemical compositions of TiO2 coated sieves were further analyzed. The antibacterial properties of sieves were also evaluated, using the bioaerosol residual test. It was obvious that all TiO2 coated sieves exhibited adequate bactericidal efficiency, destroying over 98% of bacteria. For TiO2 coated #100 and #300 mesh sieves without plasma cleaning, good TiO2 adhesion and at least 98% bactericidal efficiency were observed. The bactericidal efficiency of sieves also increased with increasing Ti content of coatings. In addition, the surface morphologies and chemical compositions of Ar plasma pre-cleaned and TiO2 coated sieves were unchanged even after being sterilized 5 times, which is very useful in the rapid temperature change environments. It is concluded that the Ar plasma pre-cleaned and TiO2 coated SS 304 sieve is a simple, economic and flexible coating method, which is easy for technical transferring and promising in the application of environmental protection fields.

The Dye-Sensitized TiO2 thin film fabricated by TiO2 nanoparticles is a novel technology with advantage in low cost, little pollution and simple in manufacturing process. The fiber-shaped reacting sites provide enlarged photo-sensing area of the TiO2 thin films. Natural dye of TCPP was applied to improve the photo absorbability in this study. Besides, a novel plasma surface activation technique employed on the thin film showed well performance compared with previous reports by heating methods. The SEM images demonstrate that the nano-TiO2 composites deposited on the fiber substrate. Degradation of acetone under 365 and 420 nm light irradiation were conducted to evaluate the photocatalytic ability of the TiO2 and TCPP/TiO2 thin films. While TiO2 thin films gel catalyst showed good photocatalytic performance with a high degradation efficiency of 99.9%, only about 80% conversion efficiency was achieved by the TCPP/TiO2 thin films reactor under 365 nm light irradiation. Although the TCPP dye on TiO2 nanoparticle shows beneficial reflection intensity in 420 nm, the acetone degradation capability of TiO2 and TCPP/ TiO2 thin films reactor decreased about 30% and 25% respectively compared with the degradation efficiency under 365 nm.

Pd/SDB (Styrene Divinylbenzene Copolymer), a hydrophobic catalyst, has been used for the destruction of volatile organic compounds (VOCs) in wastewater. Although the catalysts performed well in low VOC concentrations, they were not as effective in high VOC concentrations because of the heat removal problem. On the other hand, Pt/Zeolite contains a high silica to alumina ratio, which gives it hydrophobic characteristics and allows it to endure significantly higher temperatures than Pd/SDB. Hence, they were chosen for the treatment of wastewater containing high VOC concentrations. As expected, the catalysts presented both high conversion rates and good stability maintenance. Because of their high stability and rapid regeneration, the catalysts were regarded to be promising for industrial applications. In this study, the noble metal content of Pt/Zeolite amounted to 1.5 wt.%, and that the different temperatures and pressures collocating with different weight hourly space velocity (WHSV) were used to test the VOCs conversion efficiency. The results showed that the best reduction temperature was 450°C below the temperature- programmed reduction (TPR) process. The reaction system consisted of a continuous dripping flow with a fix-bed system and proportional integral derivative (PID) temperature controller. Selected VOCs such as methanol, ethanol, propanol and formaldehyde were investigated over the catalyst. Qualitative and quantitative analysis of the reagents and the potential organic intermediates was determined using gas chromatography with a flame ionization detector (FID). The experimental results indicated that the reaction rate is inversely proportional to the molecular weight for the compounds with the same functional group. For the same molecular weight, aldehyde is easier to destroy than alcohol. Ethanol and propanol, atypical products of incomplete oxidation of alcohols, were detected in the reaction gas. To minimize the energy consumption, we preferred liquid phase reaction since the heat of reaction could maintain the reaction temperature.

TiO2 thin films obtained by sol-gel and dipping deposition on glass fibers substrates followed by thermal treatment was used in this works. In an attempt to understand the structure and the morphology of TiO2 sol-gel thin films, analysis by X-ray diffraction (XRD) and scanning electron microscopy (SEM) are reported. Degradation of toluene under 365 nm light illumination was conducted to evaluate the photocatalytic ability of the TiO2 thin films. A special design of glass reactor allowed the UV lamp to be located in the center of the reactor. The photocatalyst reactor was then filled with TiO2 thin films/glass fibers substrates to exams the photocatalysis of toluene vapor ranged from 10 to 1,000 ppmv. Toluene depletion was sampled by gas chromatography (GC). The results showed that the photocatalytic performance of the reactor had high toluene depletion efficiency of 99.9% under 20 ppmv, and the efficiency decreased when toluene concentration were 100 and 1,000 ppmv. The improvement of the photocatalytic activity was ascribed to the fibers-based reactor provides a significantly huge surface area of the TiO2 thin films. These results will be useful and assist engineers to design photocatalyst reactors for the VOCs removal.

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.