Pollutants emissions from a light vehicle fuelled with unesterified new or waste vegetable oils: a pilot study

The emissions of regulated pollutants (CO, NOx, SO2, particles) from a light vehicle fuelled with Diesel fuel, unused and waste vegetable oils, and blends of Diesel fuel and oils were measured, as a function of engine speed. Formaldehyde emissions were also quantified, as well as the smoke opacity. The emission levels when using pure or blended oil (25%, 50%, 75%) with diesel fuel are quite similar to the ones from diesel fuel alone, but patterns are found with a small overproduction of CO together with a decrease in NO emissions for the 50% blends. No significant effect of the nature or previous use of the oil has been found.