Long-range transport and microscopy analysis of Sangay volcanic ashes in Ecuador

This study aims to conduct a spatiotemporal analysis of the long-range transportation of volcanic ashes that originates from the eruption of the Sangay volcano and reached Guayaquil during the months of June 2020; September 2020; and April 2021. The particulate matter data (PM2.5) was obtained using a low-cost air quality sensor. During the wet season of 2020 (Jan-May), PM2.5 average concentrations were 6 +/- 2 mu g m-3 while during the dry season of 2020 (July-Nov), PM2.5 average concentrations were 16 +/- 3 mu g m-3 in Guayaquil. The most prominent plumes occurred on September 20th of 2020, a month with no rain but high wind speeds created by the Andes Mountain topography to the coast. During this event, PM2.5 concentrations started at 12:00 UTC-5 in a volcanic plume event that lasted 4 h with a maximum peak of 133 + 40 mu g m-3. Electron microscopy of selected samples showed that the ashes of the three eruptions may differ in size and morphology. EDX analysis reveals that the ash contains certain elements-C, Si, Na, Mg, Al, Ca, S, and Fe-in similar proportions. In summary, this study remarks on the meteorological role and the long-range transport of Sangay volcanic ashes.