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, SO 4 2− , Cl − , NO 3 − , methanesulfonate (MSA), 210 Pb and 210 Po. 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 210 Po and 210 Pb showed no evidence for strong volcanic influences on sulfate, and NSS also was not correlated with NO 3 − , a possible tracer of continental emissions.