Abstract: Observations of atmospheric methane-sulfonic acid (MSA) and non-sea-salt sulfate (nss-SO₄²⁻ ) from December 2010 to November 2011 at Zhongshan Station are presented in this paper. MSA and nss-SO42− average concentrations were 24.2 ±37.9 ng·m^-3 (0.5–158.3 ng·m^-3) and 53.0 ± 82.6 ng·m-3 (not detected [n.d.]) – 395.4 ng·m^-3), respectively. Strong seasonal variationsof MSA and nss-SO₄²⁻with maxima in austral summer and minima in winter, were examined. The high concentrations of sulfur compounds in December may be attributed the dimethyl sulfide (DMS) emissions from the marginal ice zone, when open water near the sampling site was important in impacting the sulfur species of January and February at Zhongshan Station. In austral winter, there was almost no phytoplanktonic activity in offshore waters, and atmospheric sulfur compounds likely had long-range transport sources.

Key words: MSA, nss-SO₄²⁻, seasonal variations, East Antarctica, Zhongshan Station