Widening the gap between measurement and modelling of secondary organic aerosol properties?
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Authors
Good, Nicholas
Topping, D. O.
Duplissy, Jonathan
Meyer, Nic K.
Metzger, Axel
Turner, S. F.
Baltensperger, Urs
Ristovski, Zoran
Author (Corporation)
Publication date
2010
Typ of student thesis
Course of study
Collections
Type
01A - Journal article
Editors
Editor (Corporation)
Supervisor
Parent work
Atmospheric Chemistry and Physics
Special issue
DOI of the original publication
Link
Series
Series number
Volume
10
Issue / Number
6
Pages / Duration
2577–2593
Patent number
Publisher / Publishing institution
Copernicus
Place of publication / Event location
Göttingen
Edition
Version
Programming language
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Practice partner / Client
Abstract
The link between measured sub-saturated hygroscopicity and cloud activation potential of secondary organic aerosol particles produced by the chamber photo-oxidation of α-pinene in the presence or absence of ammonium sulphate seed aerosol was investigated using two models of varying complexity. A simple single hygroscopicity parameter model and a more complex model (incorporating surface effects) were used to assess the detail required to predict the cloud condensation nucleus (CCN) activity from the sub-saturated water uptake. Sub-saturated water uptake measured by three hygroscopicity tandem differential mobility analyser (HTDMA) instruments was used to determine the water activity for use in the models. The predicted CCN activity was compared to the measured CCN activation potential using a continuous flow CCN counter. Reconciliation using the more complex model formulation with measured cloud activation could be achieved widely different assumed surface tension behavior of the growing droplet; this was entirely determined by the instrument used as the source of water activity data. This unreliable derivation of the water activity as a function of solute concentration from sub-saturated hygroscopicity data indicates a limitation in the use of such data in predicting cloud condensation nucleus behavior of particles with a significant organic fraction. Similarly, the ability of the simpler single parameter model to predict cloud activation behaviour was dependent on the instrument used to measure sub-saturated hygroscopicity and the relative humidity used to provide the model input. However, agreement was observed for inorganic salt solution particles, which were measured by all instruments in agreement with theory. The difference in HTDMA data from validated and extensively used instruments means that it cannot be stated with certainty the detail required to predict the CCN activity from sub-saturated hygroscopicity. In order to narrow the gap between measurements of hygroscopic growth and CCN activity the processes involved must be understood and the instrumentation extensively quality assured. It is impossible to say from the results presented here due to the differences in HTDMA data whether: i) Surface tension suppression occurs ii) Bulk to surface partitioning is important iii) The water activity coefficient changes significantly as a function of the solute concentration.
Keywords
Subject (DDC)
550 - Geowissenschaften
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ISBN
ISSN
1680-7324
1680-7316
1680-7316
Language
English
Created during FHNW affiliation
No
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Gold
License
Citation
GOOD, Nicholas, D. O. TOPPING, Jonathan DUPLISSY, Martin GYSEL, Nic K. MEYER, Axel METZGER, S. F. TURNER, Urs BALTENSPERGER, Zoran RISTOVSKI, Ernest WEINGARTNER, Hugh COE und Gordan MCFIGGANS, 2010. Widening the gap between measurement and modelling of secondary organic aerosol properties? Atmospheric Chemistry and Physics. 2010. Bd. 10, Nr. 6, S. 2577–2593. DOI 10.5194/acp-10-2577-2010. Verfügbar unter: https://doi.org/10.26041/fhnw-9706