A Comparative Study of Volatile Particulate Matter Removal Efficiency: Catalytic versus Thermal Denuding of Aerosols

The Missouri S&T Thermodenuder was compared to the Catalytic Instruments CS08 Catalytic Stripper. The performance of both devices was analyzed using a propane soot aerosol generated by a laminar flame burner (miniCAST). High organic carbon and high elemental carbon flow settings on the miniCAST gave effectiveness over two regimes of aerosol hydrophobicity. Soot samples were coated with vaporized H2SO4 which was then allowed to equilibrate and condense before being sent through each denuder. The effectiveness of both devices at removing sulfuric acid was compared for both the total size distribution and that of a selected size using a Tandem Differential Mobility Analyzer and condensation particle counter system. At operating temperatures of 375 and 370°C, both devices had similar penetrations of 80% at 30nm using NaCl. Preliminary results from performance experiments show slight downshifting of particle size after passing though both devices along with possible artifacts after the Thermodenuder