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| Titel |
Temperature dependence of bromine activation due to reaction with ozone in a proxy for organic aerosols |
| VerfasserIn |
Jacinta Edebeli, Markus Ammann, Anina Gilgen, Anja Eichler, Martin Schneebeli, Thorsten Bartels-Rausch |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250126040
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| Publikation (Nr.) |
 EGU/EGU2016-5712.pdf |
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| Zusammenfassung |
| The discovery of boundary layer ozone depletion events in the Polar Regions [1] and in the
mid-latitudes [2], two areas of very different temperature regimes, begs the question of
temperature dependence of reactions responsible for these observations [3]. These ODEs
have been attributed to ozone reacting with halides leading to reactive halogens (halogen
activation) of which bromide is extensively studied, R1 – R3 [4, 5] (R1 is a multiphase
reaction).
O3 + Br−→ O2 + OBr− (R1)
OBr− + H+ ↔ HOBr (R2)
HOBr + H+ + Br−→ Br2 + H2O (R3)
Despite extensive studies of ozone-bromide interactions, the temperature dependence of
bromine activation is not clear [3]. This limits parameterization of the involved reactions and
factors in atmospheric models [3, 6]. Viscosity changes in the matrix (such as organic
aerosols) due to temperature have been shown to influence heterogeneous reaction rates and
products beyond pure temperature effect [7]. With the application of coated wall flow-tubes,
the aim of this study is therefore to investigate the temperature dependence of bromine
activation by ozone interaction while attempting to characterize the contributions of the bulk
and surface reactions to observed ozone uptake. Citric acid is used in this study as a
hygroscopically characterized matrix whose viscosity changes with temperature and
humidity.
Here, we present reactive ozone uptake measured between 258 and 289 K. The data show
high reproducibility. Comparison of measured uptake with modelled bulk uptake at
different matrix compositions (and viscosities) indicate that bulk reactive uptake
dominates, but there are other factors which still need further consideration in the
model.
References
1. Barrie, L.A., et al., Nature, 1988. 334: p. 138 - 141.
2. Hebestreit, K., et al., Science, 1999. 283: p. 55-57.
3. Simpson, W.R., et al., Atmospheric Chemistry and Physics, 2007. 7: p. 4375 -
4418.
4. Haag, R.W. and J. Hoigné, Environ Sci Technol, 1983. 17: p. 261-267.
5. Oum, K.W., et al., Geophysical Research Letters, 1998. 25(21): p. 3923-3926.
6. Abbatt, J.P.D., et al., Atmospheric Chemistry and Physics, 2012. 12(14): p.
6237-6271.
7. Steimer, S.S., et al., Atmospheric Chemistry and Physics, 2014. 14(19): p.
10761-10772. |
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