References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-7-1441-2007

The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

Aiuppa

¹ ² Franco

¹ von Glasow

³ ⁶ Allen

A. G.

⁴ D'Alessandro

² Mather

T. A.

⁵ Pyle

D. M.

⁵ Valenza

¹ ²

Dipartimento CFTA, Università di Palermo, Palermo, Italy

INGV – Sezione di Palermo, Palermo, Italy

Institut für Umweltphysik, University of Heidelberg, Germany

School of Geography, Earth and Environmental Sciences, University of Birmingham, UK

Earth Science Department, University of Oxford, UK

now at: School of Environmental Sciences, University of East Anglia, Norwich, UK

13 03 2007

7 5 1441 1450

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys.net/7/1441/2007/acp-7-1441-2007.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/7/1441/2007/acp-7-1441-2007.pdf

Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent) volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily). Sulphur dioxide (SO2), hydrogen sulphide (H2S), hydrogen chloride (HCl) and hydrogen fluoride (HF) concentrations in the volcanic plumes (typically several minutes to a few hours old) were repeatedly determined at distances from the summit vents ranging from 0.1 to ~10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from ~10 000 μg/m3at 0.1 km from Etna's vents down to ~7 μg/m3 at ~10 km distance), reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free) volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger variations in the modelled SO2/HCl ratios were predicted under cloudy conditions, due to heterogeneous chlorine cycling in the aerosol phase. The modelled evolution of the SO2/H2S ratios is found to be substantially dependent on whether or not the interactions of H2S with halogens are included in the model. In the former case, H2S is assumed to be oxidized in the atmosphere mainly by OH, which results in minor chemical loss for H2S during plume aging and produces a fair match between modelled and measured SO2/H2S ratios. In the latter case, fast oxidation of H2S by Cl leads to H2S chemical lifetimes in the early plume of a few seconds, and thus SO2 to H2S ratios that increase sharply during plume transport. This disagreement between modelled and observed plume compositions suggests that more in-detail kinetic investigations are required for a proper evaluation of H2S chemical processing in volcanic plumes.

References 1

Aiuppa, A., Bellomo, S., D'Alessandro, W., Federico, C., Ferm, M., and Valenza, M.: Volcanic plume monitoring at Mount Etna by diffusive (passive) sampling, J. Geophys. Res., 109, D21308, doi:10.1029/2003JD004481, 2004.

Aiuppa, A., Federico, C., Franco, A., Giudice, G., Gurrieri, S., Inguaggiato, S., Liuzzo, M., McGonigle, A. J. S., and Valenza M.: Emission of bromine and iodine from Mount Etna volcano, Geochem. Geophys. Geosyst., 6, Q08008, doi:10.1029/2005GC000965, 2005a.

Aiuppa, A., Inguaggiato, S., McGonigle, A. J. S., O'Dwyer, M., Oppenheimer, C., Padgett, M. J., Rouwet, D., and Valenza M.: H2S fluxes from Mt. Etna, Stromboli and Vulcano (Italy) and implications for the global volcanic sulfur budget, Geochim. Cosmochim. Acta, 69-7, 1861–1871, 2005, doi:10.1016/j.gca.2004.09.018, 2005b.

Aiuppa, A.., Federico, C., Giudice, G., and Gurrieri, S.: Chemical mapping of a fumarolic field: La Fossa Crater, Vulcano Island (Aeolian Islands, Italy), Geophys. Res. Lett., 32(13), L13309, 10.1029/2005GL023207, 12 July 2005, 2005c.

Aiuppa, A., Bellomo, S., Brusca, L., D'Alessandro, W., Di Paola, R., and Longo, M.: Major-ion bulk deposition around an active volcano (Mt. Etna, Italy), Bull Volcanol, 68(3), 255–265, doi:10.1007/s00445-005-0005-x, 2006.

Allen, A. G., Oppenheimer, C., Ferm, M., Baxter, P. J., Horrocks, L. A., Galle, B., McGonigle, A. J. S., and Duffell, H. J.: Primary sulfate aerosol and associated emissions from Masaya Volcano, Nicaragua, J. Geophys. Res., 107(D23), 4682, doi:10.1029/2002JD002120, 2002.

Allen, A. G., Mather, T. A., McGonigle, A. J. S., Aiuppa, A., Delmelle, P., Davison, B., Bobrowski, N., Oppenheimer, C., Pyle, D. M., and Inguaggiato, S.: Sources, size distribution and downwind grounding of aerosols from Mt. Etna, J. Geophys. Res., 111, D10302, doi:10.1029/2005JD006015, 2006.

Ayers, G. P., Keywood, M. D., Gillet, R. W., Manins, P. C., Malfroy, H., and Bardsley, T.: Validation of passive diffusion samplers for SO2 and NO2, Atmos. Environ., 32, 3593–3600, 1998.

Bobrowski, N., Hönninger, G., Galle, B., and Platt, U.: Detection of bromine monoxide in a volcanic plume, Nature, 423 , 273–276, 2003.

Bobrowski, N., von Glasow, R., Aiuppa, A., Inguaggiato, S., Louban, I., Ibrahim, O. W., and Platt, U.: Halogen Chemistry in Volcanic Plumes, J. Geophys. Res., in press, 2007.

Bonaccorso, A., Calvari, S., Coltelli, M., Del Negro, C., and Falsaperla, S. (Eds): Mt. Etna: Volcano Laboratory AGU Geophysical Monograph Series, 143, 2004.

Caltabiano, T., Burton, M., Giammanco, S., Allard, P., Bruno, N., Murè, F., and Romano, R.: Volcanic Gas Emissions From the Summit Craters and Flanks of Mt. Etna, 1987–2000, in: Mt. Etna: Volcano Laboratory AGU Geophysical Monograph Series, edited by: Bonaccorso, A., Calvari, S., Coltelli, M., Del Negro, C., and Falsaperla, S., 143, 111–128, 2004.

Delmelle, P.: Environmental impacts of tropospheric volcanic gas plumes, in Volcanic degassing, edited by: Oppenheimer, C., Pyle, D. and Barclay, J., Geological Society Special Publications, 213, 381–399, 2003.

Delmelle, P., Stix, J., Bourque, C. P. A., Baxter, P. J., Garcia Alvarez, J., and Barquero, J.: Dry deposition and heavy acid loading in the vicinity of Masaya Volcano, a major sulfur and chlorine source in Nicaragua, Environ, Sci. Tecnol., 35, 1289–1293, 2001.

Delmelle, P., Stix, J., Baxter, P. J., Garcia-Alvarez, J., and Barquero, J.: Atmospheric dispersion, environmental effects and potential health hazard associated with the low-altitude gas plume of Masaya volcano, Nicaragua, Bull. Volcanol., 64, 423–434, 2002.

Ferm, M.: The theories behind diffusive sampling, Paper presented at International Conference Measuring Air Pollutants by Diffusive Sampling, Montpellier, France 26–28 September 2001, 31–40, 2001.

Francis, P., Burton, M. R., and Oppenheimer, C.: Remote measurements of volcanic gas compositions by solar occultation spectroscopy, Nature, 396, 567–570, 1998.

Frische, M., Garofalo, K., Hansteen, T. H., and Borchers, R.: Fluxes and origin of halogenated organic trace gases from Momotombo volcano (Nicaragua), Geochem. Geophys. Geosys., 7, Q05020, doi:10.1029/2005GC001162, 2006.

Gerlach, T. M.: Volcanic sources of tropospheric ozone-depleting trace gases, Geochem. Geophys. Geosyst., 5, Q09007, doi:10.1029/2004GC000747, 2004.

Horrocks, L. A., Oppenheimer, C., Burton, M. R., and Duffell, H. J.: Compositional variation in tropospheric volcanic gas plumes: evidence from ground-based remote sensing, in Volcanic degassing, edited by C. Oppenheimer, D. Pyle and J. Barclay, Geological Society Special Publications, 213, 349–369, 2003.

Lee, C., Kim, Y. J., Tanimoto, H., Bobrowski, N., Platt, U., Mori, T., Yamamoto, K., and Hong, C. S.: High ClO and ozone depletion observed in the plume of Sakurajima volcano, Japan. Geophys. Res. Lett., 32 , 21809, doi:10.1029/2005GL023785, 2005.

Martin, D., Ardouin, B., Bergametti, G., Carbonelle, J., Faivre-Pierret, R., Lambert, G., and Le Cloarec, M. F.: Geochemistry of sulfur in Mt. Etna plume, J. Geophys. Res., 91, 12 249–12 254, 1986.

Martin, R. S., Mather T. A., and Pyle, D.M .: Modeling the chemistry of high temperature mixtures of magmatic and atmospheric gases, Geochem. Geophys. Geosyst., 7, Q04006, doi:10.1029/2005GC001186, 2006.

Mather, T. A., Pyle, D. M., and Oppenheimer, C.: Tropospheric Volcanic Aerosol, in Volcanism and the Earth's Atmosphere, Geophysical Monograph 139, edited by: Robock, A. and Oppenheimer, Am. Geophys. Union, Washington, D.C. 189–212, 2003a.

Mather, T. A., Allen, A. G., Oppenheimer, C., Pyle, D. M., and McGonigle, A. J. S.: Size-resolved characterisation of soluble ions in the particles in the tropospheric plume of Masaya volcano, Nicaragua: Origins and plume processing, J. Atmos.Chem., 46(3), 207–237, 2003b.

McGonigle, A. J. S., Delmelle, P., Oppenheimer, C., Tsanev, V. I., Delfosse, T., Williams-Jones, G., Horton, K., and Mather, T. A.: SO2 depletion in tropospheric volcanic plumes, Geophys. Res. Lett., 31, L13201. doi:10.1029/2004GL019990, 2004.

Métrich, N. and Clocchiatti, R.: Sulfur abundance and its speciation in oxidized alkaline melts, Geochim. Cosmochim. Acta, 60, 4151–4160, 1996.

Nicovich, J. M., Kreutter, K. D., van Dijk, C. A., and Wine, P. H.: Temperature- Dependent Kinetics Studies of the Reactions Br(2P$_3,2)$+H2S $\Downarrow \diamondsuit $ SH+HBr and Br(2P$_3,2)$+CH3SH $\Downarrow \diamondsuit $ CH3S+HBr. Heats of Formation of SH and CH$\neg $S Radicals, J. Phys. Chem., 96, 2518–2528, 1992.

Oppenheimer, C., Francis, P., and Stix, J.: Depletion rates of SO2 in tropospheric volcanic plumes, Geophys. Res. Lett., 25, 2671–2674, 1998.

Oppenheimer, C., Tsanev, V. I., Braban, C. F., Cox, R. A., Adams, J. W., Aiuppa, A., Bobrowski, N., Delmelle, P., Barclay, J., and McGonigle, A. J. S.: BrO formation in volcanic plumes, Geochimica Cosmochimica Acta, 70, 2935–2941, 2006.

Penkett, S. A., Jones, B. M. R., Brice, K. A., and Eggleton, A. E. J.: The importance of atmospheric ozone and hydrogen peroxide in oxidising sulphur dioxide in cloud and rainwater, Atmos. Environ., 13, 123–137, 1979.

Ravishankara, A. R.: Heterogeneous and multiphase chemistry in the troposphere, Science, 276, 1058–1065, 1997.

Robock, A.: Volcanic Eruptions and Climate, Rev. Geophys., 38, 191–220, doi:10.1029/1998RG000054, 2000

Robock, A. and Oppenheimer, C.: Volcanism and the Earth's atmosphere, AGU Geophysical monograph, 139, doi:10.1029/139GM03, 2003.

Sander, S. P., Friedl, R. R., Golden, D. M., Kurylo, M. J., Moortgat, G. K., Keller-Rudek, H., Wine, P. H., Ravishankara, A. R., Kolb, C. E., Molina, M. J., Finlayson-Pitts, B. J., Huie, R. E., and Orkin, V. L.: Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling. Technical Report JPL Publication 06-2, Jet Propulsion Laboratory, Pasadena, CA, 2006.

Schwandner, F. M., Seward, T. M., Gize, A. P., Hall, P. A., and Dietrich, V. J.: Diffuse emission of organic trace gases from the flank and crater of a quiescent active volcano (Vulcano, Aeolian Islands, Italy), J. Geophys. Res., 109(D4), D04301, doi:10.1029/2003JD003890, 2004.

Symonds, R., Rose, W. I., Bluth, G. J. S., and Gerlach, T. M.: Volcanic-gas studies: methods, results and applications, in: Volatiles in Magmas, edited by: Carroll, M. R. and Halloway, J. R., Rev. Mineralogy, 30, 1–66, 1994.

von Glasow, R., Sander, R., Bott, A., and Crutzen, P. J.: Modeling halogen chemistry in the marine boundary layer. 1. Cloud-free MBL, J. Geophys. Res., 107 , 4341, doi:10.1029/2001JD000 942, 2002.