Sources and elemental composition of summer aerosols in the Larsemann Hills (Antarctica)
2015
Budhavant, Krishnakant | Safai, P. D. | Rao, P. S. P.
Atmospheric aerosols play a major role in the global climate change. A better physical characterization of the chemical composition of atmospheric aerosols, especially in remote atmosphere, is an important step to reduce the current uncertainty in their effect on the radiative forcing of the climate. In the present work, surface aerosols have been studied over the Southern Ocean and over Bharati, Indian Research Station at Larsemann Hills at the Antarctic coast during the summer season of 2009–2010. Aerosol samples were collected using optical particle counter (OPC) and high-volume air sampler. PM₁₀ and PM₂.₅ aerosol samples were analyzed for various water-soluble and acid-soluble ionic constituents. The Hysplit model was used to compute the history of the air masses for their possible origin. Supplementary measurements of meteorological parameters were also used. The average mass concentration for PM₁₀ over the Southern Ocean was found to be 13.4 μg m³. Over coastal Antarctica, the mass of PM₁₀ was 5.13 μg m⁻³, whereas that of PM₂.₅ was 4.3 μg m⁻³. Contribution of marine components, i.e., Na, Cl and Mg was dominant over the Southern Ocean (79 %) than over the coastal Antarctica where they were dominant in coarse mode (67 %) than in fine mode (53 %) aerosols. The NH₄/nss-SO₄ ratio of 1.12 in PM₂.₅ indicates that the NH₄ and SO₄ ions were in the form of NH₄HSO₄. Computation of enrichment factors indicate that elements of anthropogenic origin, e.g., Zn, Cu, Pb, etc., were highly enriched with respect to crustal composition.
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