Methanol and ethanol concentrations in a Greenland ice core

Abstract The first methanol and ethanol concentrations in a Greenland ice core are reported for 14 annual samples ranging from 1686 to 1947 AD. Concentrations ranged from 83 nM to 1666 nM and 16 nM–424 nM for methanol and ethanol, respectively. Low median methanol and ethanol concentrations from 1686 to 1745 result primarily from natural emissions during a cold climate period. These concentrations provide a baseline alcohol level in deposition before impacts from various sources (e.g. naturally recovering plant populations, anthropogenic sources, and changing atmospheric oxidation chemistry) increased alcohol concentrations in the atmosphere. Concentrations of both alcohols increased after 1745 possibly due to increased biogenic and anthropogenic sources. Because both of these alcohols react with hydroxyl radicals, this increase has important implications for changing atmospheric oxidation chemistry. Samples were also analyzed for various other ice core components (e.g. aldehydes, anions, H+, DOC) to investigate possible correlation with alcohol concentrations. These ice core data are significant because they can be used to determine the extent temporal trends in alcohol concentrations were due to changes in atmospheric chemistry and varying source type and magnitude.