Aerosol chemistry of the 2021 Fagradalsfjall eruption – following major and trace elements from source to exposed communities

<p>Fissure eruptions are a pollution hazard due to their emissions of gas and aerosol particulate matter (PM) into the lower troposphere, which elevates pollutant concentrations at ground level. Alongside major gas species (e.g., H₂O, SO₂, CO₂) and minute amounts of ash, fissure eruptions emit volatile trace elements including metals and metalloids, typically transported in the atmosphere as fine particulates.</p><p>The 2021 Fagradalsfjall fissure eruption in Iceland presented a unique opportunity to better understand volatile emissions and their spread in the atmosphere. During a 5-week campaign inMarch-April 2021, we sampled the plumes from the active vents and the lava flows using ground-based instruments and Unmanned Aerial System (UAS). Size-resolved major (including sulfate and chloride) and trace element aerosol chemistry were analysed using ICP-MS and ion chromatography. We compare the emission rate and magmatic volatility of trace elements between the crater and the lava degassing; and with that of other eruptions globally.</p><p>The volcanic plume was also sampled in several downwind areas between 3 and 30 km distance from the eruption site. Using this network, we captured temporal and spatial changes in the major and trace element chemistry of the volcanic plume as it aged.</p><p><strong>&#160;</strong></p>