Influence of Biodiesel on Emissions of Criteria and Non-Criteria Primary and Secondary Pollutants

Considering the plan to increase the mixture of biodiesel in diesel oil (currently 14% in Brazil), it is becoming necessary to know the composition of exhaust gases. This study shows that most recent articles indicate that biodiesel is a suitable alternative in these circumstances, although they point out that it can have harmful effects, such as an increase in some emissions, for example carbonyls. A diesel utility van was used fueled by different mixtures of 0, 10, 15, 20 and 30% of biodiesel added to diesel, under a protocol test using a dynamometer. The emissions were collected from a constant volume sampler and transferred to a 4 m3 polytetrafluoroethylene (PTFE) reaction chamber to enable the formation of secondary pollutants, which allowed the study to be carried out without the influence of meteorological parameters. The results are highlighted for each of the pollutants and show the differences in the composition of the exhaust gases when the fuel is changed. No significant changes were observed in carbonyls emissions, but a clear reduction for benzene, toluene, ethylbenzene and xylenes (BTEX) and alkyl-PAHs (polycyclic aromatic hydrocarbons), and an increase in nitro-HPA were detected. Fine particles (< 1.8 µm) also showed an increase, but nano particles (< 180 nm) demonstrated a decrease.