Tandem configuration of differential mobility and centrifugal particle mass analyzers for investigating aerosol hygroscopic properties
Sergey S. Vlasenko1, Hang Su2, Ulrich Pöschl2, Meinrat O. Andreae2, and Eugene F. Mikhailov1,21Department of atmospheric physics, Saint-Petersburg University, St. Petersburg State University, SPbSU, SPbU, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia 2Biogeochemistry and Multiphase Chemistry Departments, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
Abstract. A tandem arrangement of Differential Mobility Analyzer and Humidified Centrifugal Particle Mass Analyzer (DMA-HCPMA) was developed to measure the deliquescence and efflorescence thresholds and the water uptake of submicron particles over the relative humidity (RH) range from 10 % to 95 %. The hygroscopic growth curves obtained for Ammonium sulfate and sodium chloride test aerosols are consistent with thermodynamic model predictions and literature data. The DMA-HCPMA system was applied to measure the hygroscopic properties of urban aerosol particles, and the kappa mass interaction model (KIM) was used to characterize and parameterize the concentration-dependent water uptake observed in the 50–95 % RH range. For DMA-selected 160 nm dry particles (mass of 3.5 fg), we obtained a volume-based hygroscopicity parameter κv ≈ 0.2, which is consistent with literature data for freshly emitted urban aerosols.
Overall, our results show that the DMA-HCPMA system can be used to measure size-resolved mass growth factors of atmospheric aerosol particles upon hydration and dehydration up to 95 % RH. The direct measurements of humidified particle mass allow avoiding complications that occur in the commonly used mobility-diameter-based HTDMA technique due to poorly defined particle morphology and density.
Vlasenko, S. S., Su, H., Pöschl, U., Andreae, M. O., and Mikhailov, E. F.: Tandem configuration of differential mobility and centrifugal particle mass analyzers for investigating aerosol hygroscopic properties, Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-249, in review, 2016.