Modeling the lava heat flux during severe effusive volcanic eruption: An important impact on surface air quality

The Reunion Island experienced its biggest eruption of Piton de la Fournaise Volcano during April 2007. Known as the eruption of the century, this event degassed more than 230 kt of SO 2 . Theses emissions led to important health issues, accompanied by environmental and infrastructure degradations. This modeling study uses the mesoscale chemical model MesoNH‐C to simulate the transport of gaseous SO 2 between 2 and 7 April, with a focus on the influence of heat fluxes from lava. This study required the implementation of a reduced chemical scheme, a basic surface model, and an estimation of lava heat fluxes in the atmospheric model. The model was able to reproduce general trends of this eruption, in particular the crossing of trade wind inversion, the SO 2 surface concentration (with highest peak of SO 2 of 600 μg m −3 observed on 4 April for western Reunion locations), and the wet deposition associated to rainfall. A sensitivity study shows that without heat fluxes over the vent and the lava flow, simulated SO 2 surface concentration are up to 45 times higher than observed.