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Editor: Karl RopkinsThis study assessed the on-road gaseous and particulate emissions from three current technology gasoline direct injection (GDI) vehicles using portable emissions measurement systems (PEMS). Two vehicles were also retrofitted with catalyzed gasoline particulate filters (GPFs). All vehicles were exercised over four routes with different topological and environmental characteristics, representing urban, rural, highway, and high-altitude driving conditions. The results showed strong reductions in particulate mass (PM), soot mass, and particle number emissions with the use of GPFs. Particle emissions were found to be highest during urban and high-altitude driving compared to highway driving. The reduction efficiency of the GPFs ranged from 44% to 99% for overall soot mass emissions. Similar efficiencies were found for particle number and PM mass emissions. In most cases, nitrogen oxide (NOx) emissions showed improvements with the catalyzed GPFs in the underfloor position with the additional catalytic volume. No significant differences were seen in carbon dioxide (CO 2 ) and carbon monoxide (CO) emissions with the vehicles retrofitted with GPFs.

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WO3/γ-Al2O3 exhibited a lower activity than WO3/SiO2 in oxidative desulfurization (ODS) of dibenzothiophene using cumene hydroperoxide as the oxidant. This could be a result of the strong interaction between WO3 and γ-Al2O3. The crystalline WO3 was more active than the tetrahedrally coordinated tungsten oxide species bound on the surface of γ-Al2O3. The loss of WO3 was negligible for WO3/SiO2 after the reaction. These features make SiO2 a promising support for the supported WO3 ODS catalyst.