Acidity of aerosol particles and of precipitation in the North Polar region and over the Atlantic

Abstract

During the Swedish polar expedition Ymer-80, measurements of the acid content of Aitken particles, of particles with radius between 0.1 and 1 μm, and of precipitation have been performed. Aitken particles were lound to contain acid. The large particles also contain acid but may react neutral or alcaline in the case of an abundance in the radius range of sea salt particles produced by heavy weather conditions. The snow collected from the pack ice surface exhibited an acid reaction to a higher degree than could be explained from incorporation of condensation nuclei. The most plausible conclusion is that in polar regions. the precipitation is additionally acidified by uptake of gases. The results demonstrate that formation of acid in aerosol particles as well as in precipitation is to be considered a natural process in the undisturbed remote troposphere.