Relating (oxygenated) Polycyclic Aromatic Hydrocarbon concentrations in East Antarctic summer to air mass origin characteristics

Abstract. Antarctica is the most remote region on Earth, and the presence of organic pollutants in its environment is of significant concern. To assess the role of atmospheric transport in the temporal variability of Polycyclic Aromatic Hydrocarbons (PAHs), backward trajectories were calculated using the FLEXTRA model for the Belgian Princess Elisabeth Station (PES; 71.95° S, 23.34° E, 1380 m a.s.l.) over the period January 2010 to February 2021. A k-means cluster analysis based on latitude, longitude, and altitude identified four distinct air mass origin clusters, with the dominant cluster representing Antarctic continental air masses from higher altitudes. The results reveal a strong seasonal pattern, with a more localized atmospheric circulation during summer in this region of East Antarctica, differing from other seasons. During four austral summer seasons from 2017/18 to 2020/21, atmospheric samples were collected by high-volume sampling and analysed for (oxygenated) PAHs ((oxy-)PAHs). Atmospheric backward trajectories were analysed for each of the collected samples to investigate the influence of air mass origin on (oxy-)PAH variability. However, no clear relationship could be established between PAH levels and atmospheric air mass origin parameters such as air mass origin cluster, temperature, distance to the station, and marine contribution. Phenanthrene was identified as the most abundant PAH at Princess Elisabeth Station, and it is suggested that its presence is governed by a seasonally distinct interplay of long-range transport and local remobilization from snow rather than by simple source-to-sink mechanisms.