Abstract. During three summer campaigns in January/February 2000, 2001 and 2002 the ionic compo-sition of the aerosol at the EPICA deep-drilling site at Kohnen Station was measured in daily resolution. In 2000 and 2002 we observed mean (±std) non-sea salt sulfate (nss-SO42-) con-centrations of 353±100 ng m-3 and 320±250 ng m-3, as well as methane sulfonate (MS) con-centrations of 59±36 ng m-3 and 74±80 ng m-3, respectively. For the summer campaign in 2001, significantly lower nss-SO42- and MS levels of 164±150 ng m-3 and 19±12 ng m-3, respectively, were typical. The mean MS/nss-SO42- ratio ranged from about 0.1 to 0.2. MS and nss-SO42- concentrations and their variability were roughly comparable to coastal stations at summer. Supported by air mass back trajectory analyses this finding documented an effi-cient long-range transport to Kohnen via the free troposphere. MS/nss-SO42- ratios exhibited a strong dependence on the MS concentration with systematically higher ratios at higher MS concentrations, a peculiarity which is also evident in a firn core drilled at this site.