We observed depletion of GEM in dilute and moderately aged (~3-7 hours) volcanic plumes. While previous work has suggested that such a depletion might occur due to volcanic bromine emissions and reactive bromine chemistry, multiple lines of evidence rule out a mostly bromine-driven process here. Instead, we hypothesized that gasparticle interactions were the underlying driver and explored possible manifestations of such a gas-particle interaction. We derived empirical interaction rate constants and constrained the magnitude of GEM scavenging in function of the volcanic submicron particle mass. Extrapolating our observations and results to the global scale, we estimated that volcanic aerosols might globally scavenge 210 (67; 480) Mg y -1 of Hg from the atmosphere.