Obtaining insight in atmospheric trace organic compound concentrations and trends in Dronning Maud Land, East Antarctica by means of long term passive and active air sampling

info:eu-repo/semantics/publishe

Year-round measurement of atmospheric volatile organic compounds using sequential sampling in Dronning Maud Land, East-Antarctica

Antarctica is considered the most pristine environment on Earth but is also characterized by its unique conditions such as the strong polar vortex and extreme cold. A detailed understanding of volatile organic compounds (VOCs) and the atmospheric oxidation reactions they undergo is essential to document biogeochemical cycles and to better understand their impact on radiative forcing. This research aims to provide a unique dataset of oxygenated (O)VOCs occurring in the Antarctic troposphere and provide insights into their temporal behavior. A home-made sequential sorbent tube auto sampler was deployed at the atmospheric observatory of the Princess Elisabeth station (71.95° S, 23.35° E, 1390 m asl) to collect 20 samples during the period from December 2019 to October 2020. The samples were analyzed consecutively by TD-GC-MS followed by direct thermal desorption of samples in a high-resolution PTR-Qi-TOFMS. Concentrations of 70 VOCs allocated to 4 different chemical groups (halogenated compounds, non-aromatic hydrocarbons, sulfur-containing compounds, and oxygenated aromatic and non-aromatic compounds) were determined. The results show temporal patterns for compounds such as bromoform (14 ± 6 ng/m3) and OVOCs such as furaldehyde (24 ± 9 ng/m³), amongst others, which are attributed to the seasonality of atmospheric conditions. Products of the atmospheric oxidation process show linear correlation indicating their mutual relationship and association with a common parent compound. The usage of an autonomous autosampler in the extreme conditions of Antarctica was demonstrated and proved to be a powerful tool in the sampling of air in such a remote location. The novel approach of using two analytical techniques boasts increased sensitivity and a broad range of compounds that can be detected, yielding the first dataset of its kind for Antarctica

Modelling the impact of cloud condensation and ice nuclei on the near-surface climate of Dronning Maud Land (East Antarctic) using the regional climate model COSMO-CLM2

By serving as condensation and ice nuclei, aerosols play a vital role in the formation of clouds. This has significant implications for the radiation balance and precipitation amounts over the Antarctic Ice Sheet, where type and amount of aerosols differ significantly from other places because of its remote location. However, that is also the reason observations are sparse, and consequently, few studies exist examining this effect. Recently, a module was added to the COSMO-CLM² regional climate model to account for the aerosol-cycle. The model was integrated for the region around the Princess Elisabeth Antarctic research station (PEA) in Dronning Maud Land for a period of 10 days in January 2016, of which the first 3 days were discarded. Varying cloud condensation and ice nuclei were prescribed to the model, based on observations from PEA. The model output was compared to observations of cloud structure and precipitation amounts taken at PEA, as well as the unmodified COSMO-CLM² model. The model integrations indicate that the number of ice nuclei has a significant impact on the microphysical composition of clouds, with higher numbers being associated with a lower amount of liquid water content of clouds and higher precipitation amounts. Additional runs are performed to confirm and extend these findings for an entire year. Recent measurements of ice nuclei particle concentrations obtained during two austral summers are also considered. Moreover, we analysed how atmospheric dynamics affect the cloud-aerosol interaction by analysing the model sensitivity for different weather regimes

Indoor and outdoor air quality assessment in daycare centres in Ghent (Belgium) in view of outdoor sleeping in an urban environment

Within Flanders, there is an increasing trend to let children sleep outdoors while in daycare. However, within an urban environment, the densely spread emission sources might affect the air quality and possibly limit the areas where outdoor sleeping is favourable. Nevertheless, there is a lack of data regarding the atmospheric pollution levels in and around daycare centres (DCC). Therefore, the focus of this study is to chemically characterize the air quality indoors, outdoors, and in specifically designed cubicles for outdoor sleeping at 12 DCCs spread over the city of Ghent (Belgium). The measuring of a very broad range of different pollutants, provides unique data for indoor and outdoor air quality at daycare centres in Ghent. The use of axial tube (for volatile organic compounds, VOCs) and Radiello (for NO2, SO2, O3) passive samplers enables multi-component sampling, resulting in time -weighted average concentrations for one week. Forty-seven VOCs are identified and, for the majority (40), in-door to outdoor concentration (I/O) ratios higher than one are found. For the remaining seven compounds (e.g. benzene) outdoor concentrations are a factor 1.3-17.9 (median) higher than indoors. Median indoor TVOC concentrations are 152 mu g/m3 and 142 mu g/m3 for the September and January campaign, respectively. Outdoors, these median TVOC concentrations are much lower (24.5 mu g/m3 and 30.6 mu g/m3). For NO2, no noticeable dif-ferences are observed between average indoor and outdoor concentrations (indoors 12 +/- 3 mu g/m3 and 13 +/- 2 mu g/m3 for the September and January campaign, respectively, and outdoors 11 +/- 3 mu g/m3 and 14 +/- 4 mu g/m3). The highest (outdoor) measured concentration is 21 +/- 1 mu g/m3. SO2 concentrations are below 2.62 mu g/m3 (LOQ). Average indoor O3 concentrations are 4 +/- 3 mu g/m3 and 2 +/- 2 mu g/m3 for the September and January campaign, respectively. Much higher values are measured outdoors (46 +/- 3 mu g/m3 and 40 +/- 11 mu g/m3), but the concentrations stayed well below legal standards

Simulating the effects of Ice-nucleating particles in Antarctica in COSMO-CLM²

&amp;lt;p&amp;gt;The remoteness of the Antarctic continent has important implications for the microphysical properties of clouds: In particular, the rare abundance of ice-nucleating particles (INP) limits the primary nucleation of ice crystals. Yet, persistent mixed-phase clouds with ice crystal number concentrations of 0.1-1l&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; are still observed in the Arctic and Antarctic. However, the ability of regional climate models to reproduce these mixed-phase clouds remains limited, much like the knowledge about their climatological effects. Thus, we added a module to the regional climate model COSMO-CLM&amp;amp;#178; aimed at improving the parametrisation of the aerosol-cycle, which allows us to prescribe different concentrations of INPs. We examined the model response to different concentrations by running it in an area around the Belgian Princess Elisabeth Station in Dronning Maud Land for one month and with four different concentration settings: The first, corresponding to the low end of INP concentrations we observed at the station, the second, corresponding to the high end of INP concentrations we observed at the station, and the third and fourth, to the low and high end of continental observations. The performance was evaluated by comparing the simulation results with radar and ceilometer observations taken at the station. Finally, we analysed the differences between the four simulations to determine the overall sensitivity of the model to variability in INP concentrations, which allows us to draw conclusions about the importance of accurately simulating processes related to ice nucleation, and about the climatological implications that a change in aerosol concentrations would have.&amp;lt;/p&amp;gt;</jats:p