Physicochemical or geochemical

• Helama, S., Arppe, L., Uusitalo, J., Holopainen, J., Mäkelä, H. M., Mäkinen, H., Mielikäinen, K., Nöjd, P., Sutinen, R., Taavitsainen, J. P., Timonen, M., (2018), Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human health, Scientific Reports, 8, 1339, 10.1038/s41598-018-19760-w