Trace elements and receptor modelling of aerosols in the antarctic peninsula

Abstract

Atmospheric aerosols were sampled continuously since December 1985 at the Brazilian Antarctic Station “Comandante Ferraz”, (62.1°S; 58.4° W) in the King George Island, Antarctic Peninsula. Stacked filter units (SFU) were used to collect fine ( d p < 2.0 μm) and coarse (2.0 μm < d p < 15 μm) particles on Nuclepore filters. The concentrations of elements with Z > 10 were measured by particle-induced X-ray emission (PIXE) analysis. The X-ray spectra were fitted for 23 elements: Na, Mg, AI, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr and Pb. The fine and coarse mass concentrations were determined by gravimetric analysis. Absolute principal factor analysis (APFA) was used to obtain the aerosol source profiles. For the coarse mode, two factors explained 95% of the data variability. The first factor had significant loadings for Na, Mg, Cl, S, Sr, K, Ca, and the coarse particle mass concentration (representing sea-salt aerosol), and the second factor had significant loadings for Al, Si, Fe, Ti, and Ca (soil dust aerosol). In the fine mode, three factors explained 94% of the data variability, and they represented sea-salt aerosol, soil dust and sulfates. The communalities for the fine and coarse mode aerosol were very high for all variables. The source profiles obtained by APFA for both fine and coarse mode aerosol were extracted for each retained factor. The sea-salt source profile agreed with the average sea-water elemental composition to within 20% for the elements Na, Mg, S, Cl, K, Ca and Br. For the soil dust component, the elements Mg, Al, Si, K, Ca, Ti, Mn, and Fe were predicted by APFA within 40% of the average bulk elemental composition for the earth crust. The source apportionment for the coarse particle mass concentration (CPM) showed that 76% of the CPM is accounted for by the sea-salt aerosol component, 4.5% by soil dust and 20% of the CPM could not be apportioned. For the fine particle mass concentration (FPM), sea-salt aerosol accounted for 80%: sulfates for 16%, soil dust for 1.1%, and 3.5% of the FPM could not be apportioned. No anthropogenic components could be distinguished.