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Secondary organic aerosol from VOC mixtures in an oxidation flow reactor

Ahlberg, Erik LU ; Falk, John LU ; Eriksson, Axel LU ; Holst, Thomas LU ; Brune, William Henry; Kristensson, Adam LU ; Roldin, Pontus LU and Svenningsson, Birgitta LU (2017) In Atmospheric Environment 161. p.210-220
Abstract

The atmospheric organic aerosol is a tremendously complex system in terms of chemical content. Models generally treat the mixtures as ideal, something which has been questioned owing to model-measurement discrepancies. We used an oxidation flow reactor to produce secondary organic aerosol (SOA) mixtures containing oxidation products of biogenic (α-pinene, myrcene and isoprene) and anthropogenic (m-xylene) volatile organic compounds (VOCs). The resulting volume concentration and chemical composition was measured using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), respectively. The SOA mass yield of the mixtures was compared to a partitioning model constructed from... (More)

The atmospheric organic aerosol is a tremendously complex system in terms of chemical content. Models generally treat the mixtures as ideal, something which has been questioned owing to model-measurement discrepancies. We used an oxidation flow reactor to produce secondary organic aerosol (SOA) mixtures containing oxidation products of biogenic (α-pinene, myrcene and isoprene) and anthropogenic (m-xylene) volatile organic compounds (VOCs). The resulting volume concentration and chemical composition was measured using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), respectively. The SOA mass yield of the mixtures was compared to a partitioning model constructed from single VOC experiments. The single VOC SOA mass yields with no wall-loss correction applied are comparable to previous experiments. In the mixtures containing myrcene a higher yield than expected was produced. We attribute this to an increased condensation sink, arising from myrcene producing a significantly higher number of nucleation particles compared to the other precursors. Isoprene did not produce much mass in single VOC experiments but contributed to the mass of the mixtures. The effect of high concentrations of isoprene on the OH exposure was found to be small, even at OH reactivities that previously have been reported to significantly suppress OH exposures in oxidation flow reactors. Furthermore, isoprene shifted the particle size distribution of mixtures towards larger sizes, which could be due to a change in oxidant dynamics inside the reactor.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Oxidation flow reactor, Secondary organic aerosol, SOA yield, VOC mixtures
in
Atmospheric Environment
volume
161
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:85018448910
ISSN
1352-2310
DOI
10.1016/j.atmosenv.2017.05.005
language
English
LU publication?
yes
id
2490d5f8-8068-41df-b4be-bcfb948f9a7e
date added to LUP
2017-05-17 09:34:14
date last changed
2017-05-17 09:34:14
@article{2490d5f8-8068-41df-b4be-bcfb948f9a7e,
  abstract     = {<p>The atmospheric organic aerosol is a tremendously complex system in terms of chemical content. Models generally treat the mixtures as ideal, something which has been questioned owing to model-measurement discrepancies. We used an oxidation flow reactor to produce secondary organic aerosol (SOA) mixtures containing oxidation products of biogenic (α-pinene, myrcene and isoprene) and anthropogenic (m-xylene) volatile organic compounds (VOCs). The resulting volume concentration and chemical composition was measured using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), respectively. The SOA mass yield of the mixtures was compared to a partitioning model constructed from single VOC experiments. The single VOC SOA mass yields with no wall-loss correction applied are comparable to previous experiments. In the mixtures containing myrcene a higher yield than expected was produced. We attribute this to an increased condensation sink, arising from myrcene producing a significantly higher number of nucleation particles compared to the other precursors. Isoprene did not produce much mass in single VOC experiments but contributed to the mass of the mixtures. The effect of high concentrations of isoprene on the OH exposure was found to be small, even at OH reactivities that previously have been reported to significantly suppress OH exposures in oxidation flow reactors. Furthermore, isoprene shifted the particle size distribution of mixtures towards larger sizes, which could be due to a change in oxidant dynamics inside the reactor.</p>},
  author       = {Ahlberg, Erik and Falk, John and Eriksson, Axel and Holst, Thomas and Brune, William Henry and Kristensson, Adam and Roldin, Pontus and Svenningsson, Birgitta},
  issn         = {1352-2310},
  keyword      = {Oxidation flow reactor,Secondary organic aerosol,SOA yield,VOC mixtures},
  language     = {eng},
  month        = {07},
  pages        = {210--220},
  publisher    = {Elsevier},
  series       = {Atmospheric Environment},
  title        = {Secondary organic aerosol from VOC mixtures in an oxidation flow reactor},
  url          = {http://dx.doi.org/10.1016/j.atmosenv.2017.05.005},
  volume       = {161},
  year         = {2017},
}