We used the Tropospheric Ultraviolet and Visible (TUV) Radiation Model 49 to estimate UVA (315 -400 nm) and UVB (280 -315 nm) radiation, as well as photolysis rate constants. We evaluated UV radiation for geographical coordinates of Maïdo, but an altitude of 2500 masl (~350 m above Maïdo), considering that volcanic plumes traveled above ground. We assumed a total ozone column of 270 DU (based on the "TROPOspheric Monitoring Instrument" -TROPOMI) and cloudless conditions, which we confirmed with in-situ measured solar radiation.