The DMPS does not detect particles larger than ~ 700 nm in diameter and may have lower collection efficiency toward the limits of its detection range 32 . As fine particle mass in a volcanic plume often has a mass peak close to ~ 1 µm 52-55 , PM0.7DMPS most likely underestimates the submicron particle mass in the volcanic plumes. While the total submicron mass was not measured, we count with filter-based measurements of water-soluble inorganic ions in PM0.95, among them sulfate (see section 2.2.1.5). It has already been reported that sulfate dominated the mass of inorganic ions at Maïdo during the April -June 2018 volcanic episode 34 .