Mercury oxidation by hydrochloric acid over the V 2 O 5 (WO 3 )/TiO 2 commercial SCR catalyst was investigated. Both fresh and aged catalysts with honeycomb structure, which were exposed to a coal combustion flue gas in a coal-fired boiler for over 71 000 h, were examined. The aged catalysts were characterized by X-ray and SEM-EDX analysis to examine the presence of ash deposition on the surface. The mercury oxidation rate was enhanced by increasing HCl concentrations and inhibited strongly by the presence of NH 3 . This behavior could be explained by a kinetic model assuming that HCl competes for the catalyst active sites against NH 3 . As the catalyst operation time increased, the mercury oxidation rate was observed to decrease considerably in the presence of NH 3 while NO reduction rate was apparently nearly unchanged. By examining aged catalysts, deposits stemming from fly ash and SO 2 /SO 3 were observed to accumulate continuously on the catalyst surface. The ash deposited on the surface may partially block the active catalyst sites and decrease their number. The decrease of the number of active sites on the catalyst surface caused NH 3 to remain unreacted in the honeycomb catalyst. The decrease of the Hg 0 oxidation rate was caused by the inhibition effect of NH 3 remaining in the catalyst.

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The concentrations of organophosphate flame retardants (OPFRs) in the indoor air and dust were measured in 25 unoccupied cars in Japan. In the indoor air of the cars, most OPFRs were neither detected nor found at a concentration lower than the method quantification limit. The highest concentration (1500 ng m) was obtained for tris(1-chloro-2-propyl) phosphate (TCIPP). By contrast, many OPFRs were detected in the dust samples collected from the interior of the cars. TCIPP and tris(2-ethylhexyl) phosphate (TEHP) were present at the highest concentrations at 390 μg g (in dust from car seats) and 640 μg g (in dust from car floor mats), respectively. The highest median concentrations (35 μg g for car seats, 53 μg g for car floor mats) were obtained for tris(2-butoxyethyl) phosphate (TBOEP). According to the results of our exposure assessment, the typical exposures to OPFRs via inhalation in car cabins ranged from 9.0×10 to 7.8×10 ng kg-bw day. The typical exposures to OPFRs via dust ingestion ranged from 9.2×10 to 8.8×10 ng kg-bw day. We compared these results with the ref-erence doses for OPFRs and found that, based on cur-rent information about the toxicities of OPFRs, exposure to OPFRs in car cabins via inhalation and dust ingestion is unlikely to have adverse human health effects.

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