Tracking far-range air pollution induced by the 2014–15 Bárdarbunga fissure eruption (Iceland)

Abstract. The 2014–15 Holuhraun lava-flood eruption of Bárdarbunga volcano (Iceland) has emitted prodigious amounts of sulfur dioxide into the atmosphere. This eruption caused a large-scale episode of air pollution throughout Western Europe in September 2014, the first event of this magnitude recorded in the modern era. We gathered a wealth of complementary observations from satellite sensors (OMI, IASI), ground-based remote sensing (lidar, sunphotometry, differential optical absorption spectroscopy) and ground-level air quality monitoring networks to characterize both the spatial-temporal distributions of volcanic SO2 and sulfate aerosols as well as the dynamics of the planetary boundary layer. Time variations of dynamical and microphysical properties of sulfate aerosols in the aged low-tropospheric volcanic cloud, including loading, vertical distribution, size distribution and single scattering albedo, are provided. Retrospective chemistry-transport simulations capture the correct temporal dynamics of this far-range air pollution event but fail to reproduce the magnitude of SO2 concentration at ground-level. Improving forecasts of large-scale volcanogenic air pollution will require refined emission parameters and adapted model grid resolution to accurately describe both long-range transport and local boundary layer dynamics.