During Polarstern cruise ANT-XXV/5 in April/May 2009, the marine atmosphere was sampled via PTFE (Polytetrafluorethylen) tubing extending from the front of the upper deck to labs on the main deck of r/v Polarstern and then analyzed for elemental mercury in air (Hg0-air) using the same Tekran 2537A as for Hg0-water measurements. The time interval of Hg0-air measurements was 5-min with gaps of about 20 min each hour because of intermittent Hg0-water measurements. The data were checked for potential contamination during tailwind situations (relative wind speed and direction) and doubtful values were removed. The detection limit was 0.1 ng L-1 (on ANT-XXV/5: 5 times the Hg0-air values were below the detection limit).