The Effect of Biodiesel on PAHs, Nitro-PAHs and Oxy-PAHs Emissions from a Light Vehicle Operated Over the European and the Artemis Driving Cycles

This study examines the effects of neat soy-based biodiesel (B100) and its 50% v/v blend (B50) with low sulphur automotive diesel on vehicle PAH emissions. The measurements were conducted on a chassis dynamometer with constant volume sampling (CVS) according to the European regulated technique. The vehicle was a Euro 2 compliant diesel passenger car, equipped with a 1.9 litre common-rail turbocharged direct injection engine and an oxidation catalyst. Emissions of PAHs, nitro-PAHs and oxy-PAHs were measured over the urban phase (UDC) and the extra-urban phase (EUDC) of the type approval cycle (NEDC). In addition, for evaluating realistic driving performance the non-legislated Artemis driving cycles (Urban, Road and Motorway) were used. Overall, 12 PAHs, 4 nitro-PAHs, and 6 oxy-PAHs were determined. The results indicated that PAH emissions exhibited a reduction with biodiesel during all driving modes. However, some of the nitro- and oxy-PAH compounds were found to increase with biodiesel. The use of pure biodiesel resulted in increases in some of the PAH compounds when compared to B50. PAH emissions were significantly increased during the cold-start UDC phase. Engine operating conditions (load and speed) also affected PAH emissions.