Articles | Volume 10, issue 5
Atmos. Chem. Phys., 10, 2257–2267, 2010
Atmos. Chem. Phys., 10, 2257–2267, 2010

  03 Mar 2010

03 Mar 2010

Aerosol analysis using a Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS): a new approach to study processing of organic aerosols

R. Holzinger1, J. Williams2, F. Herrmann2, J. Lelieveld2, N. M. Donahue3, and T. Röckmann1 R. Holzinger et al.
  • 1Institute for Marine and Atmospheric research Utrecht, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
  • 2Max Planck Institute for Chemistry, Mainz, Germany
  • 3Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh PA 15213, USA

Abstract. We present a novel analytical approach to measure the chemical composition of organic aerosol. The new instrument combines proton-transfer-reaction mass-spectrometry (PTR-MS) with a collection-thermal-desorption aerosol sampling technique. For secondary organic aerosol produced from the reaction of ozone with isoprenoids in a laboratory reactor, the TD-PTR-MS instrument detected typically 80% of the mass that was measured with a scanning mobility particle sizer (SMPS). The first field deployment of the instrument was the EUCAARI-IOP campaign at the CESAR tall tower site in the Netherlands. For masses with low background values (~30% of all masses) the detection limit of aerosol compounds was below 0.2 ng/m3 which corresponds to a sampled compound mass of 35 pg. Comparison of thermograms from ambient samples and from chamber-derived secondary organic aerosol shows that, in general, organic compounds from ambient aerosol samples desorb at much higher temperatures than chamber samples. This suggests that chamber aerosol is not a good surrogate for ambient aerosol and therefore caution is advised when extrapolating results from chamber experiments to ambient conditions.

Final-revised paper