La Palma PM10 ash particle geometry and adherence to pulmonary cell tissue

While studies have shown adverse health effects associated with volcanic eruptions are thought to result from resultant gases and ash particle clouds, the precise reasons remain unclear. However, the shape of particles has previously been shown to influence their ability to adhere to human cancer cells (He and Park 2016). Furthermore grain size and the presence of silica are thought to be important in understanding respiratory effects associated with volcanic ash particles.

We have previously shown that volcanic ash particles can have sharp appearing surface features from 3D confocal microscopy (Wertheim et al. 2017). The aim of this study was to examine the 3D appearance, chemistry and adherence to cells of volcanic ash particles from the September 2021 La Palma eruption in particles of size PM₁₀ as they are considered of particular interest in respiratory conditions. Volcanic ash particles collected from the first day of the eruption were imaged using confocal scanning laser microscopy and scanning electron microscopy in order to assess their 3D appearance and geometry. In addition, 2D shape and elemental analysis, obtained from secondary and backscattered electron imaging, was performed to link ash particle geometry with composition.

Initial results confirming the angular (3D-fragmented) nature of PM₁₀ and smaller particles from the La Palma eruption, suggest an ability to adhere to cells. Experiments to confirm this by exposing A549 human adenocarcinomic epithelial cells to La Palma ash particles are ongoing.