Laboratory observation of oligomers in the aerosol from isoprene/NOx photooxidation

doi:doi:10.1029/2006GL026523

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L13805, 5 PP., 2006
doi:10.1029/2006GL026523

Laboratory observation of oligomers in the aerosol from isoprene/NO_x photooxidation

J. Dommen

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

A. Metzger

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

J. Duplissy

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

M. Kalberer

Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland

M. R. Alfarra

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

A. Gascho

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

E. Weingartner

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

A. S. H. Prevot

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

B. Verheggen

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

U. Baltensperger

Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland

Compounds assigned to be oxidation products of isoprene (2-methyl-1,3-butadiene) have recently been observed in ambient aerosols, suggesting that isoprene might play an important role in secondary organic aerosol (SOA) formation due to its large global source strength. SOA yields from photooxidation of isoprene and NO_x in a chamber agree fairly well with previous data. Matrix assisted laser desorption/ionization mass spectrometry showed the formation of high molecular weight compounds over the course of 15-hour experiments. Concurrently, the volatility of the SOA decreased markedly as observed by a tandem differential mobility analyzer. The volume fraction remaining of SOA at 150°C increased steadily from 5 to 25% during the same experiments. These observations are attributed to oligomerization reactions occurring in the aerosol phase. Under dry conditions a lower volatility was observed.

Received 7 April 2006; accepted 30 May 2006; published 6 July 2006.

Citation: Dommen, J., A. Metzger, J. Duplissy, M. Kalberer, M. R. Alfarra, A. Gascho, E. Weingartner, A. S. H. Prevot, B. Verheggen, and U. Baltensperger (2006), Laboratory observation of oligomers in the aerosol from isoprene/NO_x photooxidation, Geophys. Res. Lett., 33, L13805, doi:10.1029/2006GL026523.

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