Real‐time measurements of the concentration and isotope composition of atmospheric and volcanic CO 2 at Mount Etna (Italy)

We present unprecedented data of real-time measurements of the concentration and isotope composition of CO2 in air and in fumarole-plume gases collected in 2013 during two campaigns at Mount Etna volcano, which were made using a laser-based isotope ratio infrared spectrometer. We performed approximately 360 measurements/h, which allowed calculation of the δ13C values of volcanic CO2 the fumarole gases of Torre del Filosofo (2900-m-above sea level) range from -3.24-±-0.06‰ to -3.71-±-0.09‰, comparable to isotope ratio mass spectrometry (IRMS) measurements of discrete samples collected on the same dates. Plume gases sampled more than 1-km from the craters show a δ13C-=2.2-±-0.4‰, in agreement with the crater fumarole gases analyzed by IRMS. Measurements performed along ∼17-km driving track from Catania to Mount Etna show more negative δ 13C values when passing through populated centers due to anthropogenic-derived CO2 inputs (e.g., car exhaust) the reported results demonstrate that this technique may represent an important advancement for volcanic and environmental monitoring. Key Points Real-time data of CO 2 content and δ13C in atmospheric/volcanic gases This study opens new perspective for the community for volcanic surveillance