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Effect of salt seed particle surface area, composition and phase on secondary organic aerosol mass yields in oxidation flow reactors

Ahlberg, Erik LU ; Eriksson, Axel LU ; Brune, William H.; Roldin, Pontus LU and Svenningsson, Birgitta LU (2019) In Atmospheric Chemistry and Physics 19(4). p.2701-2712
Abstract

Atmospheric particulate water is ubiquitous, affecting particle transport and uptake of gases. Yet, research on the effect of water on secondary organic aerosol (SOA) mass yields is not consistent. In this study, the SOA mass yields of an α-pinene and m-xylene mixture, at a concentration of 60 μgm-3, were examined using an oxidation flow reactor operated at a relative humidity (RH) of 60% and a residence time of 160 s. Wet or dried ammonium sulfate and ammonium nitrate seed particles were used. By varying the amount of seed particle surface area, the underestimation of SOA formation induced by the short residence time in flow reactors was confirmed. Starting at a SOA mass concentration of 5 μgm-3, the maximum yield increased by a factor... (More)

Atmospheric particulate water is ubiquitous, affecting particle transport and uptake of gases. Yet, research on the effect of water on secondary organic aerosol (SOA) mass yields is not consistent. In this study, the SOA mass yields of an α-pinene and m-xylene mixture, at a concentration of 60 μgm-3, were examined using an oxidation flow reactor operated at a relative humidity (RH) of 60% and a residence time of 160 s. Wet or dried ammonium sulfate and ammonium nitrate seed particles were used. By varying the amount of seed particle surface area, the underestimation of SOA formation induced by the short residence time in flow reactors was confirmed. Starting at a SOA mass concentration of 5 μgm-3, the maximum yield increased by a factor of 2 with dry seed particles and on average a factor of 3.2 with wet seed particles. Hence, wet particles increased the SOA mass yield by 60% compared to the dry experiment. Maximum yield in the reactor was achieved using a surface area concentration of 1600 μm2 cm-3. This corresponded to a condensational lifetime of 20 s for low-volatility organics. The O V C ratio of SOA on wet ammonium sulfate was significantly higher than when using ammonium nitrate or dry ammonium sulfate seed particles, probably due to differences in heterogeneous chemistry.

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organization
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type
Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
19
issue
4
pages
12 pages
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • scopus:85062353599
ISSN
1680-7316
DOI
10.5194/acp-19-2701-2019
language
English
LU publication?
yes
id
a9f455cf-64d9-483e-8021-dd4a89cdc249
date added to LUP
2019-03-15 10:54:03
date last changed
2019-04-10 04:21:09
@article{a9f455cf-64d9-483e-8021-dd4a89cdc249,
  abstract     = {<p>Atmospheric particulate water is ubiquitous, affecting particle transport and uptake of gases. Yet, research on the effect of water on secondary organic aerosol (SOA) mass yields is not consistent. In this study, the SOA mass yields of an α-pinene and m-xylene mixture, at a concentration of 60 μgm-3, were examined using an oxidation flow reactor operated at a relative humidity (RH) of 60% and a residence time of 160 s. Wet or dried ammonium sulfate and ammonium nitrate seed particles were used. By varying the amount of seed particle surface area, the underestimation of SOA formation induced by the short residence time in flow reactors was confirmed. Starting at a SOA mass concentration of 5 μgm-3, the maximum yield increased by a factor of  2 with dry seed particles and on average a factor of 3.2 with wet seed particles. Hence, wet particles increased the SOA mass yield by  60% compared to the dry experiment. Maximum yield in the reactor was achieved using a surface area concentration of  1600 μm2 cm-3. This corresponded to a condensational lifetime of 20 s for low-volatility organics. The O V C ratio of SOA on wet ammonium sulfate was significantly higher than when using ammonium nitrate or dry ammonium sulfate seed particles, probably due to differences in heterogeneous chemistry.</p>},
  author       = {Ahlberg, Erik and Eriksson, Axel and Brune, William H. and Roldin, Pontus and Svenningsson, Birgitta},
  issn         = {1680-7316},
  language     = {eng},
  number       = {4},
  pages        = {2701--2712},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Atmospheric Chemistry and Physics},
  title        = {Effect of salt seed particle surface area, composition and phase on secondary organic aerosol mass yields in oxidation flow reactors},
  url          = {http://dx.doi.org/10.5194/acp-19-2701-2019},
  volume       = {19},
  year         = {2019},
}