Particle number concentration and particle matter emissions from an indirect injection diesel light duty vehicle are statistically examined to reveal significant differences using eight nonoxygenate, one oxygenate, and the reference fuel. All fuels are of very low sulfur (<43 ppmw) and aromatics (<23.7% vol.) concentration. Analysis of variance is applied on particle samples collected from raw exhaust by an Electrical Low Pressure Impactor and on filter measurements conducted in the dilution tunnel over the Urban and the Extra Urban Driving Cycles. Statistically significant increase on both the number and the mass of emitted particles is established with increasing sulfur and aromatics content accompanied by a marginal increase of the mean particle size. Total number differs by ～3 times and mass by 50% between the most and least refined ofthe fuels tested. Finally, use of the oxygenate fuel provides a ～ 20% reduction of both the mass and the number over an equivalent, nonoxygenated fuel.
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