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, SO42 -, Cl-, NO3-, methanesulfonate (MSA), Pb-210 and Po-210. Sea salt concentra tions were relatively high compared with previous reports, with Na, averagi ng 45 ng m(-3). Chloride was depleted, by similar to 65% compared with its ratio to Na in seawater. Non-sea salt sulfate (NSS) avera, ged 212 ng m-, a nd 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 a nd NSS were correlated, the data set is not sufficiently robust to draw a q uantitative conclusion concerning the fraction of NSS that is biogenic. Dat a for Po-210 and Pb-210 showed no evidence for strong volcanic influences o n sulfate, and NSS also was not correlated with NO3-, a possible tracer of continental emissions.