AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Characterization of the Aerodyne Mini-Aerosol Mass Spectrometer
ANITA JOHNSON, J. Doug Goetz, Edward Fortner, Urs Rohner, Michael Cubison, Marc Gonin, Thorsten Hohaus, John Jayne, Douglas Worsnop, Peter DeCarlo, Drexel University
Abstract Number: 510 Working Group: Instrumentation and Methods
Abstract The Aerodyne mini-Aerosol Mass Spectrometer (mini-AMS) has been developed to facilitate size-resolved aerosol chemical composition measurements in a more compact space with lower power demands. Maintaining the high sensitivity of previous versions of the AMS was a key goal of this new development. The design of the mini-AMS has been updated with a more compact vacuum system utilizing new split flow pump technology and a smaller vacuum chamber. While the new compact design reduced the overall footprint of the aerosol mass spectrometer, other non-ideal characteristics arose. Higher air beam signal, and reduced particle transmission were seen with the original design. To optimize the sensitivity, reduce the airbeam signal, and improve the small particle transmission, laboratory experiments were performed. These included the detailed investigation of the optimal vacuum pressures in the differentially pumped system, and particle transmission experiments. Intercomparison with a Soot Particle-Aerosol Mass Spectrometer (SP-AMS) was performed during a field deployment to Lake Mokoma, Pennsylvania in the summer of 2012. The intercomparison showed similar measurements with the mini-AMS and the SP-AMS with the regression comparison of key aerosol species of sulfate and organics showing slopes of 0.949, and 0.615 and R2 of 0.81, and 0.71, respectively. Comparison of the mini-AMS calculated volume to a co-located Brechtel Scanning Electrical Mobility Sizer also showed similar agreement.