Atmos. Chem. Phys. Discuss., 11, 25871-25907, 2011
www.atmos-chem-phys-discuss.net/11/25871/2011/
doi:10.5194/acpd-11-25871-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Analysis of high mass resolution PTR-TOF mass spectra from 1,3,5-trimethylbenzene (TMB) environmental chamber experiments
M. Müller1, M. Graus1,*, A. Wisthaler1, A. Hansel1, A. Metzger2, J. Dommen3, and U. Baltensperger3
1Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
2Ionicon Analytik Gesellschaft m.b.H, Innsbruck, Austria
3Paul Scherrer Institut, Villigen, Switzerland
*current address: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA

Abstract. A series of 1,3,5-trimethylbenzene (TMB) photo-oxidation experiments was performed in the 27-m3 Paul Scherrer Institute environmental chamber under various NOx conditions. A University of Innsbruck prototype high resolution Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOF) was used for measurements of gas and particulate phase organics. The gas phase mass spectrum displayed ~200 ion signals during the TMB photo-oxidation experiments. Molecular formulas CNmHnNoOp were determined and ion signals were separated and grouped according to their C, O and N numbers. This allowed to determine the time evolution of the O:C ratio and of the average carbon oxidation state OSC of the reaction mixture. Both quantities were compared with master chemical mechanism (MCMv3.1) simulations. The O:C ratio in the particle phase was about twice the O:C ratio in the gas phase. Average carbon oxidation states of secondary organic aerosol (SOA) samples OSCSOA were in the range of −0.34 to −0.31, in agreement with expected average carbon oxidation states of fresh SOA (OSC = −0.5 − 0).

Citation: Müller, M., Graus, M., Wisthaler, A., Hansel, A., Metzger, A., Dommen, J., and Baltensperger, U.: Analysis of high mass resolution PTR-TOF mass spectra from 1,3,5-trimethylbenzene (TMB) environmental chamber experiments, Atmos. Chem. Phys. Discuss., 11, 25871-25907, doi:10.5194/acpd-11-25871-2011, 2011.
 
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