It is obvious that the atmosphere above Antarctica is the cleanest part of the Earth's troposphere and can be employed as a large clean air laboratory to study natural conditions comparable to atmospheric processes prevailed elsewhere in pre-industrial times. The nearly completely ice covered Antarctic continent is virtually free of aerosol sources while the Southern Ocean is by far the dominant source to the Antarctic aerosol body, making atmospheric sea salt and biogenic sulfur the major aerosol components. Terrestrial sources are limited to some insular rocky regions (on the Antarctic Peninsula, in the coastal dry valleys and on high mountain ranges) and volcanic activity of Mt. Erebus. Nowadays, minor anthropogenic emissions arising from fossil fuel combustion during research and tourism activities may be considered as well. On the whole these natural and anthropogenic sources constitute local or regional trace element emissions of mineral dust and specific heavy metals which are of minor importance for the overall aerosol budget of Antarctica. Therefore, Antarctica offers an outstanding place to study the background composition and the natural biogeochemical cycling of aerosol.The main task of the aerosol and trace gas observatory at Neumayer III Station is to provide continuous, year-round as well as long-term data records for important gaseous and particulate trace components of the troposphere. This collection features the aerosol absorption coefficients at seven wavelengths, measured by the 7-wavelength aethalometer (Model AE33, Magee Scientific). The intake of the aerosol inlet can be found on top of the observatory at approx. 5-7 m above ground. The data sets present the results of these long term observations for the respective over-wintering periods, new datasets will be added each year. For additional information about the observatory visit homepage: https://www.awi.de/en/science/long-term-observations/atmosphere/antarctic-neumayer/air-chemistry.html.

Important notice: BC concentrations are extremely low at Neumayer, typically lower than the instrumental noise level referring to 1 hour averages (between 0.04 and 0.05 Mm-1). Notwithstanding, we archived hourly averages, but one has to be aware that negative values may not be removed when smoothing the data or when calculating averages with lower temporal resolution, otherwise the results would exhibit a substantial positive bias!