Weekly resolved characterization of tropospheric Volatile Organic Compounds (VOCs) and partially oxidized VOCs (po-VOCs) in Dronning Maud Land, East Antarctica, using thermal desorption - gas chromatography – orbitrap high resolution mass spectrometry

Volatile organic compounds (VOCs) play a key role in atmospheric chemistry. They contribute to the formation of tropospheric ozone and lead to the formation of secondary organic aerosols (SOAs), which affect the Earth's radiation budget. Emitted from both anthropogenic and biogenic sources, VOCs undergo complex atmospheric reactions that transform them into more oxygenated, polar, and less volatile compounds—partially oxidized VOCs (po-VOCs)—which can condense onto particles or form new aerosols. VOCs and po-VOCs can also be transported over long distances, reaching remote regions like the polar areas. These regions are vital components of the Earth's system, interacting with global oceans, the atmosphere, and ecosystems. Once considered pristine environments, they are now increasingly affected by anthropogenic contaminants, raising concerns about their environmental impacts. However, the short atmospheric lifetime of VOCs (ranging from minutes to hours to a few days), their complex atmospheric chemistry, and the logistical challenges of polar research have limited our understanding of their role in climate-relevant processes, especially in Antarctica, and compared to other climate-forcing agents. During this event, we will present the results from the 2023–2024 Belgian Antarctic Research Expedition in Dronning Maud Land, East Antarctica, focusing on trace organic compounds in the atmosphere. This includes (i) the development of an analytical method using thermal desorption (TD) coupled with gas chromatography–Orbitrap high resolution mass spectrometry (GC–Orbitrap–HRMS) for the simultaneous identification and quantification ~100 trace organic compounds, including both VOCs and po-VOCs with diverse physicochemical properties; and (ii) the characterization of weekly atmospheric samples. We identified and quantified the chemical species present in the Antarctic atmosphere, analyzed seasonal variations in their composition and transformation, and explored potential sources of both VOCs and po-VOCs. This detailed and accurate determination of the presence and concentration levels of VOCs and po-VOCs in the Antarctic atmosphere is essential for improving our understanding of the atmospheric chemistry, sources, and behavior of VOCs and po-VOCs in polar environments.