DIESEL EMISSIONS IN VIENNA

A direct apportionment of diesel emissions has been made possible by marking all the diesel fuel used by the vehicles in Vienna by a normally not occurring and easily detectable substance. All emitted diesel particles thus were marked with the tracer and by analyzing the atmospheric samples for the marking substance it was found that the mass concentrations of diesel particles in the atmosphere varied between 5 and 23 mu g m** minus **3. Busy streets and calm residential areas show less difference in mass concentration than expected. The deposition of diesel particles on the ground has been determined by collecting samples from the road surface. The concentration of the marking substance was below the detection limit before the marking period and a year after the period. During the period when marked diesel fuel was used, the concentrations of the diesel particles settling to the ground was 0. 012-0. 07 g g** minus **1 of collected dust. A positive correlation between the diesel vehicle density and the sampled mass of diesel vehicles exists. Additional study results are discussed.