Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 14, 6035-6048, 2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
18 Jun 2014
Heterogeneous reaction of N2O5 with airborne TiO2 particles and its implication for stratospheric particle injection
M. J. Tang1,2, P. J. Telford1,4, F. D. Pope3, L. Rkiouak1,5, N. L. Abraham1,4, A. T. Archibald1,4, P. Braesicke1,4,*, J. A. Pyle1,4, J. McGregor6, I. M. Watson2, R. A. Cox1, and M. Kalberer1 1Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
2School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
3School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK
4National Centre for Atmospheric Science, NCAS, UK
5Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, UK
6Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK
*now at: IMK-ASF, Karlsruhe Institute of Technology, Karlsruhe, Germany
Abstract. Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space has been suggested as a solar-radiation management scheme for the mitigation of global warming. TiO2 has recently been highlighted as a possible candidate particle because of its high refractive index, but its impact on stratospheric chemistry via heterogeneous reactions is as yet unknown. In this work the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated for the first time, at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ~1.0 × 10−3 at low RH, increasing to ~3 × 10−3 at 60% RH. The uptake of N2O5 onto TiO2 is then included in the UKCA chemistry–climate model to assess the impact of this reaction on stratospheric chemistry. While the impact of TiO2 on the scattering of solar radiation is chosen to be similar to the aerosol from the Mt Pinatubo eruption, the impact of TiO2 injection on stratospheric N2O5 is much smaller.
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Citation: Tang, M. J., Telford, P. J., Pope, F. D., Rkiouak, L., Abraham, N. L., Archibald, A. T., Braesicke, P., Pyle, J. A., McGregor, J., Watson, I. M., Cox, R. A., and Kalberer, M.: Heterogeneous reaction of N2O5 with airborne TiO2 particles and its implication for stratospheric particle injection, Atmos. Chem. Phys., 14, 6035-6048,, 2014.
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