Use of rare earth tracers for the study of diesel emissions in the atmosphere

The emissions of diesel vehicles mainly contain soot, which is difficult to distinguish from soot originating from other sources. The use of a tracer which can be detected in extremely low mass concentrations and does not occur normally in the atmospheric aerosol can help to differentiate between aerosols from different sources. The rare earth element Dysprosium has proven useful for this purpose. It can be detected by neutron activation analysis in quantities of nanograms and does not occur naturally.An organic, diesel soluble Dysprosium compound was added to the fuel. During the combustion process the Dysprosium is oxidized and attaches to the formed soot particles. For the atmospheric filter samples an extraction technique was used.This marking method has been successfully applied for an extended field experiment.