Chemical composition of atmospheric aerosol collected at Syowa Station

Abstract

Atmospheric aerosol samples were collected at Syowa Station, Antarctica, on a 47mm millipore filter with 0.45μm pore size, using an air-pump. Air sampling volumes ranged from 10m^3 to 30m^3,which were collected about 30m windward of the Laboratory of Environmental Science at Syowa Station. After that, all samples were stored for the analysis in laboratory. The trace elements such as Al, Fe, Mn, Zn and Cu in these samples were determined by the atomic absorption spectrophotometric method with a graphite furnace atomizer. Enrichment factor, E_, is calculated for the trace elements in atmospheric aerosol samples. Enrichment factor is defined as the element/Al ratio in atmospheric aerosol samples divided by the element/Al ratio in crustal rocks based on the table of MIYAKE (Elements of Geochemistry, Maruzen, 290p, 1965). For the trace elements such as Mn, Fe, Zn and Cu, enrichment factors at Syowa Station are the same order of magnitude as the value at the South Pole in the southern hemisphere and over the North Atlantic Ocean in the northern hemisphere reported by ZOLLER et al. (Science, 183,199,1974) and DUCE et al. (Science, 187,59,1975). From the results, enrichment factors suggest that Fe and Mn are likely to be associated with a source largely derived from crustal rocks. But, Zn and Cu have such high values for enrichment factors that a normal crustal weathering source for these elements must be ruled out. Oxides of these elements have a high volatility, as measured by the elemental boiling point. During the dispersion process, a certain fraction of the original source material escapes into atmosphere as particles. If, however, this dispersion process occurs at elevated temperatures, these volatile elements of the original source material may be emitted as gases or vapor. If this volatilization is anywhere near upon quantitatively, a significant enrichment will have occurred. And then, one possible source for these elements in the atmosphere may be either volcanic activity or the combustion of fossil fuel. The results suggest that the high enrichment factors may be due to anthropogenic rather than natural sources.