Non-sea salt sulfate and other aerosol constituents at the South Pole during ISCAT

Bulk aerosol samples collected at the South Pole were analyzed for Na, SO₄^2-, Cl^-, NO₃^-, methanesulfonate (MSA), ²¹⁰Pb and ²¹⁰Po. Sea salt concentrations were relatively high compared with previous reports, with Na, averaging 45 ng m^-3 Chloride was depleted by ∼65% compared with its ratio to Na in seawater. Non-sea salt sulfate (NSS) averaged 212 ng m^-3, and less than 5% of the sulfate was from sea salt. The mean concentration of MSA (an indicator of marine biogenic sulfur) was 12 ng m^-3, and the MSA/NSS mass ratio (0.059) was similar to that in Antarctic ice. Although MSA and NSS were correlated, the data set is not sufficiently robust to draw a quantitative conclusion concerning the fraction of NSS that is biogenic. Data for ²¹⁰Po and ²¹⁰Pb showed no evidence for strong volcanic influences on sulfate, and NSS also was not correlated with NO₃^-, a possible tracer of continental emissions.