The 2018 Mt. Mayon eruption: A physicochemical characterization of inhalable ash particles collected in Legazpi City, Albay, Philippines

Abstract

Volcanic ash is considered a respiratory hazard because of its potentially bio-toxic components and size.  In this investigation, a personal cascade impactor with an air pump was used to collect airborne ash particles from an evacuation center in Legazpi City, Albay during the unrest of Mt. Mayon on 8 February 2018. The PM_2.5 mass concentration for the site (42.79 µg/m³) exceeded the prescribed 24-hour-averaged 25 µg/m³ WHO limit while the PM₁₀ mass concentration (45.54 µg/m³) is within the 50 µg/m³ WHO limit. The size distribution of ash particles indicated that fine-grained ash (0.5-1.0 µm) had the highest contribution to total particulate count. Elemental analysis via Scanning Electron Microscope with Energy Dispersive X-ray spectrometer identified the following elements: C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Fe, Cu, Zn, and Mo in the volcanic ash.