Detailed carbonyls emissions from ethanol-blended gasoline (containing 10% v/v, ethanol, E-10) and biodiesel-ethanoldiesel (BE-diesel) were carefully investigated on an EQ491i gasoline engine equipped with a three-way-catalyst (TWC) and a Commins-4B diesel engine. In engine-out emissions for the gasoline engine, total carbonyls from E-10 varied in the range of 66.7-99.4 mg kW À1 h À1, which was 3.1-8.2% less than those from fossil gasoline (E-0). In tailpipe emissions, total carbonyls from E-10 varied in the range of 9.2-20.7 mg kW À1 h À1, which were 3.0-61.7% higher than those from E-0. The total carbonyls emissions from BE-diesel were 1-22% higher than those from diesel at different engine operating conditions. Compared with fossil fuels, E-10 can slightly reduce CO emission, and BE-diesel can substantially decrease PM emission, while both alternative fuels increased slightly NO x emission. r

A new kind of biobriquette, with scallop shell as desulfurizer, was developed in this study, and its self-desulfurization behavior was studied by combustion experiments. For comparison and further understanding on the self-desulfurization characteristics, the biobriquettes with Tsukumi limestone and calcium hydroxide as desulfurizers were also investigated experimentally. The influence of the furnace temperature, types of coal and desulfurizer, and structure of added desulfurizer on the behavior of desulfurization was elucidated by measuring the time concentration history of SO2 emission in combustion flue gas and calculating the desulfurization efficiency. The desulfurization efficiency was not sensitive to the temperature in the range 973−1173 K. However, the efficiency was strongly affected by coal type, and it changed from about 25 to 67% for the eight tested types of coals under the same experiment conditions. The desulfurization efficiency has been found to also be a function of the calcination temperature of desulfurizer. On the basis of experimental results, a shrinking-core reaction model was used to simulate the desulfurization process during the char combustion of biobriquette by a finite volume numerical method. The calculated results generally agreed with the experimental results. Finally, an improvement on the biobriquette structure, namely dual layered biobriquette, was proposed and tested in order to improve the desulfurization efficiency.

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a b s t r a c tThe atmospheric mixing ratios of methacrolein (MACR) and methyl vinyl ketone (MVK), the two specific products from isoprene oxidation in the atmosphere, were measured in Beijing from March to November, 2006. Distinct amounts of MACR and MVK were detected during vegetable growing seasons from April to October with ambient levels of 0.11-0.67 ppbv and 0.19-1.36 ppbv, respectively. The reacted isoprene and its ozone formation potentials (OFPs) in Beijing were evaluated in the range of 0.49-3.46 ppbv and 6.4-44.7 ppbv, respectively, from April to October. OFP of the reacted isoprene accounted for 10.6-23.6% of the total OFPs of VOCs (including carbonyls and isoprene) and 6.38-29.9% of the photo-chemically produced ozone. The maximum OFP of the original emitted isoprene prior to its photo-oxidation was calculated as 56.0 ppbv in August. The contribution from the reacted isoprene in Beijing to HCHO formation was also estimated to be in the range of 0.35-2.45 ppbv from April to October, which accounted for 4.6-11.5% of ambient HCHO.

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