Table . Summary of observed magnitudes and instrumentation used in this study (see Figure ). GEM was measured at Maïdo with a 15-minute time resolution with a Tekran 2537A analyzer, as already described in detail in Koenig et al. (2023) . The instrument was maintained and regularly calibrated according to standard GMOS (Global Mercury Observation System) procedures. While standard GMOS procedures usually imply working with hourly averages, here we work directly with the 15-minute resolution data set to better constrain the time evolution of the observed volcanic GEM depletion events, which were of short duration. We report the concentrations of GEM, as well as all other in-situ measured magnitudes described further below, at standard conditions of 273.14 K and 1013.25 hPa (STP).