Emissions of fuel metals content from a diesel vehicle engine

This study was set out to assess the characteristics and significance of metal contents emitted from diesel engines. We found that the emitted concentrations of crust elements (including Al, Ca, Fe, Mg, and Si) were much higher than those of anthropogenic elements (including Ag, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Sr, Ti, V, and Zn) from diesel vehicle engine exhausts under the transient-cycle condition. The emission concentrations of particulate matters from diesel vehicle engine were inversely proportional to the specified engine speeds. To the contrary, the increase of engine speeds resulted in increase of fractions of metal contents in particulate matters. We conducted simple linear regression analysis to relate the emission rates of the metal contents in vehicle exhaust to the consumption rates of metal contents in diesel fuel. This study yielded R2=0.999 which suggests that the emission of the metal contents in vehicle exhaust could be fully explained by the consumption of metal contents in diesel fuel. For illustration, we found that the annual emission rates of both crust and anthropogenic elements from all diesel engine vehicles (=269 000 and 58 700 kg yr−1, respectively) were significantly higher than those from the coal power plant, electrical arc furnace, and coke oven (=90 100 and 1660 kg yr−1, 2060 and 173 kg yr−1, and 60 500 and 3740 kg yr−1, respectively) in Taiwan area. The relatively high amount of metal contents emitted from diesel engines strongly suggests that the measurement on the control of metal contents in diesel fuel should be taken in the future.