Levels and patterns of C1C4/C9 organic nitrates were measured for the first time in Antarctica. The sampling wasdone by adsorptive enrichment on Tenax TA followed by thermodesorption cold-trap high resolution capillary gaschromatography with electron capture detection. 270 l air on-column have been analyzed this way. C1C9 alkylmononitrates, C2C4 alkyl dinitrates, C2C4 hydroxy alkyl nitrates, and halocarbons could be identifed in air samplescollected near the German Neumayer Research Station, Antarctica, in February 1999. Volatile biogenic and anthropogenichalocarbons were used to assess the origin of the air parcels analyzed. The average concentration measuredfor Levels and patterns of C1C4/C9 organic nitrates were measured for the .rst time in Antarctica. The sampling wasdone by adsorptive enrichment on Tenax TA followed by thermodesorption cold-trap high resolution capillary gaschromatography with electron capture detection. 270 l air on-column have been analyzed this way. C1C9 alkylmononitrates, C2C4 alkyl dinitrates, C2C4 hydroxy alkyl nitrates, and halocarbons could be identi.ed in air samplescollected near the German Neumayer Research Station, Antarctica, in February 1999. Volatile biogenic and anthropogenichalocarbons were used to assess the origin of the air parcels analyzed. The average concentration measuredfor C2C6 alkyl nitrates was in the range of 9.2 +/- 1.8 ppt(v), while the sum of the mixing ratios of six C2C4 hydroxyalkyl nitrates was in the range of 1.1 +/- 0.2 ppt(v). Moreover, C2C4 alkyl dinitrates were found at levels near thedetection limit of 0.10.5 ppt(v). The concentrations of organic nitrates found in Antarctic air represent ultimatebaseline levels due to chemical and physical loss processes during long-range transport in the air. The South Atlanticand the Antarctic Ocean as a general secondary source for organic nitrates in terms of an air/sea exchange equilibriumhas to be evaluated yet, but it seems logical. Our results confirm the common assumption that there are no biogenicmarine sources of C2C9 organonitrates. We have found a level of >80 ppt(v) for methyl nitrate. This level if it can beconfirmed in a systematic survey requires a strong biogenic source of methyl nitrate in the Antarctic Ocean.