Gas/particle partitioning of carbonyls in the photooxidation of isoprene and 1,3,5-trimethylbenzene
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Published Version
Date
2008-06-26
Authors
Healy, Robert M.
Wenger, John C.
Metzger, Axel
Duplissy, Jonathan
Kalberer, Markus
Dommen, Josef
Journal Title
Journal ISSN
Volume Title
Publisher
Copernicus Publications on behalf of the European Geosciences Union (EGU)
Published Version
Abstract
A new denuder-filter sampling technique has been used to investigate the gas/particle partitioning behaviour of the carbonyl products from the photooxidation of isoprene and 1,3,5-trimethylbenzene. A series of experiments was performed in two atmospheric simulation chambers at atmospheric pressure and ambient temperature in the presence of NOx and at a relative humidity of approximately 50%. The denuder and filter were both coated with the derivatizing agent O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) to enable the efficient collection of gas- and particle-phase carbonyls respectively. The tubes and filters were extracted and carbonyls identified as their oxime derivatives by GC-MS. The carbonyl products identified in the experiments accounted for around 5% and 10% of the mass of secondary organic aerosol formed from the photooxidation of isoprene and 1,3,5-trimethylbenzene respectively. Experimental gas/particle partitioning coefficients were determined for a wide range of carbonyl products formed from the photooxidation of isoprene and 1,3,5-trimethylbenzene and compared with the theoretical values based on standard absorptive partitioning theory. Photooxidation products with a single carbonyl moiety were not observed in the particle phase, but dicarbonyls, and in particular, glyoxal and methylglyoxal, exhibited gas/particle partitioning coefficients several orders of magnitude higher than expected theoretically. These findings support the importance of heterogeneous and particle-phase chemical reactions for SOA formation and growth during the atmospheric degradation of anthropogenic and biogenic hydrocarbons.
Description
Keywords
Atmospheric modeling , Carbonyl compound , Filter , Gas , Isoprene , Particle motion , Partition coefficient , Partitioning , Photooxidation , Sampling
Citation
Healy, R.M., Wenger, J.C., Metzger, A., Duplissy, J., Kalberer, M. and Dommen, J. (2008) 'Gas/particle partitioning of carbonyls in the photooxidation of isoprene and 1,3,5-trimethylbenzene', Atmospheric Chemistry and Physics, 8(12), pp. 3215-3230. doi:10.5194/acp-8-3215-2008