Atmos. Chem. Phys., 21, 3371–3393, 2021 https://doi.org/10.5194/acp-21-3371-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Halogen activation in the plume of Masaya volcano: field observations and box model investigations Julian Rüdiger1,2, Alexandra Gutmann1, Nicole Bobrowski3,4, Marcello Liotta5, J. Maarten de Moor6, Rolf Sander4, Florian Dinger3,4, Jan-Lukas Tirpitz3, Martha Ibarra7, Armando Saballos7, María Martínez6, Elvis Mendoza7, Arnoldo Ferrufino7, John Stix8, Juan Valdés9, Jonathan M. Castro10, and Thorsten Hoffmann1 1Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University, Mainz, Germany 2Environmental Chemistry and Air Research, Technical University Berlin, Berlin, Germany 3Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany 4Max Planck Institute for Chemistry, Mainz, Germany 5Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Italy 6Observatorio Vulcanológico y Sismológico de Costa Rica Universidad Nacional, Heredia, Costa Rica 7Instituto Nicaragüense de Estudios Territoriales, Managua, Nicaragua 8Department of Earth and Planetary Sciences, McGill University, Montreal, Canada 9Laboratorio de Química de la Atmósfera, Universidad Nacional, Heredia, Costa Rica 10Institute of Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany Correspondence: Thorsten Hoffmann (
[email protected]) Received: 25 March 2020 – Discussion started: 22 June 2020 Revised: 9 January 2021 – Accepted: 26 January 2021 – Published: 4 March 2021 Abstract. Volcanic emissions are a source of halogens in the sensing observations (differential optical absorption spec- atmosphere. Rapid reactions convert the initially emitted hy- troscopy; DOAS). The reactive fraction of bromine increased drogen halides (HCl, HBr, and HI) into reactive species such from 0.20 ± 0.13 at the crater rim to 0.76 ± 0.26 at 2.8 km as BrO, Br2, BrCl, ClO, OClO, and IO.