Amino acids in polar aerosols

Amino acids are recognized as significant components of atmospheric particles and they could be involved in cloud formation [1], act as ice-forming nuclei and affect pollutants scavenging and secondary aerosol formation[2,3]. As amino acids have a wide range of reactivities, they can help determine the atmospheric transport of particles and drops [2]. Several sources affect atmospheric amino acids, complicating the possibility of identifying their origin. Polar regions offer an unique opportunity to investigate the global atmospheric characteristics and to conduct source apportionment studies of such compounds. In this study we report the results from the determination of 20 free amino acids (FAAs) in 30 aerosol samples collected in polar sites at the Gruvenbadet Station, Ny-Ålesund, from April, 19 to September 14, 2010 and at the Campo Faraglione station, in the Terranova Bay, from November, 3, 2004 to January, 10, 2005. Samples were processed and analyzed using a previous developed method [4]. Total FAA concentrations resulted generally higher in the Arctic than in the Antarctic samples, that showed different FAA content and patterns. The dominant compounds were glycine and serine, which accounted together for at least the 30% of the total FAAs concentration, in both Arctic and Antarctic samples. Size segregation of Arctic aerosol in 6 dimensional classes allowed to study the amino acids size distribution, evidencing higher concentrations in the finest fraction (<0.49 ?m) in almost all samples. Some samples showed a more complex distribution, suggesting the presence of local derived aerosol. Local aerosol sources, as volcanic activity and human induced fires, affected FAA concentrations and distribution in the samples collected during these events. Based on the different FAAs reactivity and the back trajectory analysis, we determine marine derived aerosol as the major amino acid source for both Arctic and Antarctica, demonstrating the contribution of long range transport