Intercomparison of five mobility size spectrometers for measuring atmospheric submicrometer aerosol particles

This report presents results from an intercomparison of five mobility size spectrometers (two Grimm SMPS, one TSI long-SMPS, one TSI nano-SMPS, and one IfT-TDMPS) for the determination of number concentrations and number size distributions of submicrometer aerosol particles. The intercomparison was conducted under controlled laboratory conditions with ambient aerosol at the research site "Eisenbahnstrasse" in Leipzig. Number size distributions and concentrations measured at this site are representative for a street canyon aerosol. In general, the intercomparison gave satisfying results of the number size distribution in the range between 20 and 200 nm (deviations of maximum 20%). The uncertainty increases however for particles larger than 200 nm and smaller than 20 nm. The reason for these deviations might be differences in the correction functions for particle losses, poor counting statistics, and bipolar charge distributions used in the inversion routines of the different instruments to calculate the size distribution. The particle number concentrations are comparable within +/- 12% or better between four instruments (excluding the TSI nano-SMPS) for the size range 40 to 350