Sulphur dioxide (SO2) gas emissions from volcanic eruptions can degrade air traffic safety. SO2 serves as a precursor to sulphuric acid, a highly corrosive substance capable of damaging aircraft engines when they pass repeatedly through volcanic sulfur-rich plumes. Predicting the concentration of volcanic SO2 in the atmosphere is therefore of utmost importance for the safety of passengers and crew. Sentinel-5P/TROPOMI, and SUOMI-NPP/OMPS low-Earth orbiting ultraviolet spectrometers measure total SO2 columns from the Earth's surface to the upper atmosphere with different sensitivies near the surface. TROPOMI, with its better spatial and spectral resolutions, stands out in particular. The MetOp-IASI low-Earth orbiting infrared spectrometers also measure total SO2 columns, but with a lower spatial resolution than TROPOMI and a lower sensitivity to SO2 in the lower layers of the atmosphere. Different methods exists to forecast the spreading of volcanic SO2 plumes. The first method consists in applying a source inversion procedure to estimate the released SO2 flux values and altitude of injection at high temporal resolution. A source inversion module has been developed combining the use of the CHIMERE regional scale Eulerian chemistry-transport model with SO2 total columns observed by TROPOMI, OMPS or IASI instruments (Behera et al 2023). The second approach consists in assimilating observed SO2 total columns into the model following a 3D-Var approach. This method is applied in the semi-lagragian chemistry transport model MOCAGE where SO2 total columns from TROPOMI and IASI are assimilated on both global and regional domains. The aim of this study is to compare the plume dispersal model simulations obtained with MOCAGE by assimilation of total SO2 columns or with SO2 emissions retrieved from CHIMERE source inversion. This study would be extended to estimate SO2 emissions at high temporal resolution and assimilate satellite data simultaneously to improve forecasting of volcanic SO2 plume.