AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
First Field Measurements of Volatility- and Polarity-Resolved Organic Aerosol Using the Volatility and Polarity Separator (VAPS)
RAUL MARTINEZ, Brent Williams, Yaping Zhang, Nathan Kreisberg, Susanne Hering, David Worton, Allen H. Goldstein, Jose-Luis Jimenez, Thorsten Hohaus, John Jayne, Douglas Worsnop, Washington University in St. Louis
Abstract Number: 398 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Discrepancies between modeled and measured atmospheric organic aerosol (OA) have shown the need for in situ instrumentation to better characterize the sources, formation mechanisms, and atmospheric evolution of ambient OA. We have developed the Volatility and Polarity Separator (VAPS) for hourly measurements of volatility- and polarity-resolved OA detected using high-resolution time-of-flight mass spectrometry (HR-ToFMS). Here, atmospheric OA is inertially impacted for a half hour, thermally desorbed into an oven for volatility separation, thermally pulsed through a short polar GC column for polarity separation, and finally detected by HR-ToFMS. This novel instrument increases the mass throughput of ambient OA in comparison to traditional GC due to shorter transfer paths and passivated coatings. Molecular separation resolution is sacrificed for this increased mass transfer, but the high-resolution mass spectral data recovers information such as elemental composition to determine aerosol oxidation state.
Here we report on laboratory testing and the first field deployment of the VAPS system. Preliminary results of volatility- and polarity-resolved OA measured from the surface site in Centreville, AL during the Southern Oxidant and Aerosol Study (SOAS) will be presented. VAPS data is explored to provide new insight into the underlying chemistry and chemical evolution of anthropogenically influenced biogenic SOA.