New insights on metals in the Arctic aerosol in a climate changing world

• Published in: The Science of the total environment 2020-11, Vol.741, p.140511-140511, Article 140511
• Main Authors: Becagli, Silvia, Caiazzo, Laura, Di Iorio, Tatiana, di Sarra, Alcide, Meloni, Daniela, Muscari, Giovanni, Pace, Giandomenico, Severi, Mirko, Traversi, Rita
• Format: Article
• Language: English
• Subjects: Aerosol; Arctic; Greenland; Metals; PM10; Thule
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.140511

Ship traffic, population, infrastructure development, and mining activities are expected to increase in the Arctic due to its rising temperatures. This is expected to produce a major impact on aerosol composition. Metals contained in atmospheric particles are powerful markers and can be extremely helpful to gain insights on the different aerosol sources. This work aims at studying the sources of metals in the Arctic aerosol sampled at the Thule High Arctic Atmospheric Observatory (THAAO; Greenland, 76.5°N 68.8°W). Due to the particular composition of Greenlandic soils and to properties of other sources, it was possible to find several signatures of natural and anthropogenic aerosols transported from local and long-range regions. Arctic haze (AH) at Thule builds up on long-range transported aerosol mainly from Canada and Nord America. From a chemical standpoint, this aerosol is characterized by a high concentration of sulfate, Pb, As and Cd and by a La/Ce ratio larger than 1. The Ti/Al and Fe/Al ratios in the AH aerosol are lower (Ti/Al = 0.04 w/w; Fe/Al = 0.79 w/w) than for local aerosol (Ti/Al = 0.07 w/w; Fe/Al = 0.89 w/w). Conversely, aerosol arising from coastal areas of South-West Greenland is characterized by a high concentration of V, Ni, and Cr. These metals, generally considered anthropogenic, arise here mainly from natural crustal sources. In some summer samples, however, the V/Ni ratio becomes larger than 3. In particular, cases displaying this characteristic ratio, as also shown by backward trajectories, are associated with sporadic transport to Thule of ship aerosol from ships passing through Baffin Bay and arriving to Thule during summer. Although further measurements are necessary to confirm the discussed results, the analysis carried out in this work on a large number of metals sampled in coastal Greenland aerosol is unprecedented. [Display omitted] •Metals in aerosol samples from THAAO (Thule) are determined by ICP – AES.•Arctic Haze is characterized by high concentration of Pb, As and Cd and La/Ce > 1.•V, Ni and Cr are not from anthropic sources, but generally arise from Greenland soils.•Sporadic evidence of ship aerosol having V/Ni > 3 are evident in some summer samples.•Ti/Al and Fe/Al can be used as local and long range crustal aerosol fingerprints.