Daylight Promotes a Transient Uptake of SO2 by Icelandic Volcanic Dust
- 1IMT Nord Europe, Université de Lille, CERI EE, F-59000 Lille, France (jerome.lasne@imt-nord-europe.fr)
- 2Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- 3Earth & Life Institute, Université Catholique de Louvain, Croix Du Sud 2, 1348 Louvain-la-Neuve, Belgium
- 4Agricultural University of Iceland, Keldnaholt, 112 Reykjavik, Iceland
Volcanic eruptions release large amounts of ash in the atmosphere, accounting for 5 - 7.5% of the total primary aerosol emission. The accompanying outgassing emits mostly water, carbon dioxide and sulfur dioxide (SO2). During the 2010 eruption of the Eyjafjallajokull volcano, an average SO2 mixing ratio of 40 ppb was measured in the plume [1]. Volcanic areas such as Iceland are very active aeolian regions; as a consequence, 30 to 40 Tg of previously deposited Icelandic volcanic dust are re-suspended by winds annually [2]. In this environment, SO2 can interact with volcanic dust (v-dust) in the presence of water vapour and UV light. Assessing the heterogeneous interaction of SO2 with the surface of v-dust under UV-irradiation is therefore of crucial importance to understand its budget. Moreover, the quantification of SO2 uptake by v-dust is necessary to understand the global SO2 cycle, and to implement models with laboratory data characterizing heterogeneous processes [3].
To this aim, we have investigated the interaction of SO2 with the surface of natural Icelandic v-dust samples with laboratory experiments [4,5]. A Coated-Wall Flow Tube reactor allowed determination of the steady-state uptake (γSS) and of the transient number of SO2 molecules taken up by v-dust (NS) in a broad range of relative humidity (0.1%<RH<72%) and irradiance (JNO2 = 0-4.5×10-3 s-1) values. Interestingly, γSS values are the same in the dark and under UV-irradiation. NS values however, largely increase under UV-irradiation, and with RH. Moreover, the amplification factor NS,UV/NS,dark increases linearly with: (i) the surface Ti concentration, (ii) the photon flux, and (iii) RH. These results reveal the importance of the heterogeneous photo-enhanced reactivity of SO2 on natural v-dust samples, and advocate for a better inclusion of these processes in atmospheric models.
1 Heue et al., Atmos. Chem. Phys. 11, 2973 (2011)
2 Arnalds et al., Aeolian Res. 20, 176 (2016)
3 Maters et al., J. Geophys. Res. - Atmos. 122, 10077 (2017)
4 Urupina et al., Atmos. Environ. 217, 116942 (2019)
5 Lasne et al., Env. Sci. Atm., in revision
How to cite: Lasne, J., Urupina, D., Maters, E., Delmelle, P., Dagsson-Waldhauserova, P., Romanias, M., and Thevenet, F.: Daylight Promotes a Transient Uptake of SO2 by Icelandic Volcanic Dust, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9808, https://doi.org/10.5194/egusphere-egu22-9808, 2022.
