Tandem configuration of differential mobility and centrifugal particle mass analyzers for investigating aerosol hygroscopic properties

Other literature type English OPEN
Vlasenko, Sergey S. ; Su, Hang ; Pöschl, Ulrich ; Andreae, Meinrat O. ; Mikhailov, Eugene F. (2016)

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&thinsp;% to 95&thinsp;%. 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&ndash;95&thinsp;% RH range. For DMA-selected 160&thinsp;nm dry particles (mass of 3.5&thinsp;fg), we obtained a volume-based hygroscopicity parameter <i>&kappa;</i><sub>v</sub>&thinsp;&approx;&thinsp;0.2, which is consistent with literature data for freshly emitted urban aerosols. <br><br> 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&thinsp;% 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.
Share - Bookmark