Concentrations, particle-size distributions, and dry deposition fluxes of aerosol trace elements over the Antarctic Peninsula in austral summer

Abstract

Abstract. Size-segregated particulate air samples were collected during the\naustral summer of 2016–2017 at Palmer Station on Anvers Island, western Antarctic Peninsula,\nto characterize trace elements in aerosols. Trace\nelements in aerosol samples – including Al, P, Ca, Ti, V, Mn, Ni, Cu, Zn, Ce,\nand Pb – were determined by total digestion and a sector field inductively\ncoupled plasma mass spectrometer (SF-ICP-MS). The crustal enrichment factors\n(EF crust ) and k -means clustering results of particle-size distributions\nshow that these elements are derived primarily from three sources: (1)\xa0regional crustal emissions, including possible resuspension of soils\ncontaining biogenic P, (2)\xa0long-range transport, and (3)\xa0sea salt. Elements\nderived from crustal sources (Al, P, Ti, V, Mn, Ce) with\nEF crust were dominated by the coarse-mode particles\n( >1.8 µm ) and peaked around 4.4\u2009 µm in diameter,\nreflecting the regional contributions. Non-crustal elements (Ca, Ni, Cu, Zn,\nPb) showed EF crust>10 . Aerosol Pb was primarily dominated\nby fine-mode particles, peaking at 0.14–0.25\u2009 µm , and likely was\nimpacted by air masses from southern South America based on air mass back\ntrajectories. However, Ni, Cu, and Zn were not detectable in most size\nfractions and did not present clear size patterns. Sea-salt elements (Ca,\nNa + , K + ) showed a single-mode distribution and peaked at 2.5–4.4\u2009 µm . The estimated dry deposition fluxes of mineral dust for the\naustral summer, based on the particle-size distributions of Al measured at\nPalmer Station, ranged from 0.65 to 28\u2009mg\u2009m −2 \u2009yr −1 with a mean of\n 5.5±5.0 \u2009mg\u2009m −2 \u2009yr −1 . The estimated dry deposition fluxes\nof the target trace elements in this study were lower than most fluxes\nreported previously for coastal Antarctica and suggest that atmospheric\ninput of trace elements through dry deposition processes may play a minor\nrole in determining trace element concentrations in surface seawater over\nthe continental shelf of the western Antarctic Peninsula.