Evaluation of mass measurement techniques for soot with different size distributions and OC ∕ TC contents

Abstract. This study focuses on measuring mass concentration of soot aggregates generated with a Mini-CAST burner. The experiments were performed in a test bench able to generate soot particles with different size distributions and different OC/TC ratios. With this soot production, we assessed the mass concentration measurements based on three online instruments (TEOM, PPS and MA300) and two offline concentration determination (OC/TC and SMPS), considering the gravimetric measurement as a reference. The findings demonstrate that the TEOM and the quantification based on the thermo-optical OC/TC analyser performed within acceptable limits of 10 % in comparison to the gravimetric reference measurement, over a wide range of OC/TC, mass concentration and size distribution. The Pegasor Particle Sizer (PPS) mass concentration measurement which is based on the aerosol electrical charging is calibrated for a reference size distribution, and we suggested a correction of the mass concentration measurement based on the aerosol Fuchs active surface, that proved to efficient within the limits of this study. Finally, we confirmed that the mass concentration measurements obtained with the MA300 aethalometer are OC/TC ratio and wavelength dependent, and we were able to establish OC/TC limits for the overall mass concentration evaluation with the infrared and ultraviolet wavelengths.