Free and combined L- and D-amino acids in Arctic aerosol

Aerosol samples were collected with a high-volume cascade impactor with a 10 day sampling frequency at the Gruvebadet observatory, close to Ny-Ålesund (Svalbard Islands). A total of 42 filters were analyzed for free and combined amino acids, as they are key components of bio-aerosol. This article provides the first investigation of free and combined L- and d-amino acids in Arctic atmospheric particulate matter. The main aim of this study was to determine how these compounds are distributed in size-segregated aerosols after short-range and long-range atmospheric transport and understand the possible sources of amino acids. The total load of free amino acids ranged from 2.0 to 10.8 pmol m^-3, while combined amino acids ranged from 5.5 to 18.0 pmol m^-3. At these levels amino compounds could play a role in the chemistry of cloud condensation nuclei and fine particles, for example by influencing their buffering capacity and basicity. Free and combined amino acids were mainly found in the fine aerosol fraction (<0.49 μm) and their concentrations could be affect by several sources, the most important of which were biological primary production and biomass burning.