Intercomparison of mobility particle sizers (MPS)

Mobility particle sizers are widely used for the measurement of ultrafine a erosols in the environment as well as at workplaces. The question arises ab out the comparability of the different systems' measurements. For assessing this, eleven institutes from Austria, Switzerland and Germany with their d evices participated in an intercomparison exercise, which took place in the testing ground of the Institut fur Gefohrstoff-Forschung - IGF in Dortmund . The test aerosols were generated by a diesel engine and by a soot generat or. According to the outcome of this intercomparison it is essential to gua rantee uniform sampling conditions and instrument parameters for getting co mparable results. Attention should be paid to the correct adjustment of the flow rates and to the applied software. User skill is very important. On t hese conditions the MPS-technique is a valid toot to measure size distribut ions and number concentrations of ultrafine particles and the comparability of the results is regarded to be acceptable. The intercomparison will be r epeated on refined conditions for finding out the variability and the limit s of the different device configurations.