Anna Breuninger

The chemical composition throughout the atmosphere changes as a consequence of urbanization, developing industry and anthropogenic activities. Especially the upper troposphere and lower stratosphere (UTLS) is highly sensitive to these changes in chemical composition. With increasing anthropogenic emissions, the urgency to understand the changing chemical composition and its impact on the UTLS grows.Organophosphates are one of the most prominent anthropogenic tracers, as they are solely man-made and found ubiquitously in the environment. They are widely used as flame retardants and plasticizers and have already been found in pristine environments such as the Arctic and are considered as chemicals of emerging concern. So far, they have been studied in air, water, sediment, and sludge and their human exposure and human and ecological risk has been assessed (Wang et al. 2020). Research on outdoor air and particle-bound organophosphates has been steadily growing over the years, however, the UTLS remains a poorly studied region.In this study, we target the question of how meteorological conditions influence the chemical composition and thereby use organophosphates as anthropogenic tracers throughout the UTLS. Here, we present results from the TPEx campaign, conducted during June 2024 over Germany. Results from eight scientific flights, probing different regions of the UTLS during different meteorological conditions, were analyzed. With our in-house developed and manufactured Sampler for Organic Aerosol Particles (SOAP), we were able to collect a total of 27 filters throughout the whole campaign. Subsequently using ultra-high performance liquid chromatography, coupled with high-resolution Orbitrap mass spectrometry, we analyzed the organic fraction of aerosols. With this setup a non-target analysis allowed for the identification of unknown compounds and especially yet understudied organophosphates in the UTLS.We identified five distinct meteorological conditions by using tracer-tracer correlations, cloud water content as well as water vapor content and categorized each filter respectively. For each meteorological condition, a distinct chemical composition was identified using molecular fingerprinting. As a first result, compounds like C8H19O4P and C8H19O3PS, which are found in the troposphere as well as the stratosphere, seem to disappear during cloudy conditions and are less abundant in combination with high water vapor mixing ratios. Simultaneously, a mix of thiophosphates, which are possible transformation products of organophosphates, becomes more abundant during high water vapor mixing ratios. We further aim to quantify various organophosphates and transformation products to understand occurrence, transportation and potential global distribution, as they are unambiguous tracers for the anthropogenic impact. Wang, X., Zhu, Q., Yan, X., Wang, Y., Liao, C., Jiang, G. (2020c). A review of organophosphate flame retardants and plasticizers in the environment: Analysis, occurrence and risk assessment. Sci. Total Environ. 731, 139071. https://doi.org/10.1016/j.scitotenv.2020.13907

Air pollution adversely affects human health, with studies consistently linking it to exposure to particulate matter. However, differential toxicity remains to be established to improve monitoring and mitigation efforts. This study examines the oxidative potential (OP) of fine particulate matter using the dithiothreitol (DTT) assay as a proxy for toxicity. We analyzed 42 ambient particle filter samples from Frankfurt, Germany, and Beijing, China, focusing on water-soluble organic compounds. The aqueous extracts were analyzed for metal content via inductively coupled plasma-mass spectrometry and for organic compounds through ultrahigh performance liquid chromatography-high-resolution mass spectrometry. Utilizing a chelating agent to remove metals allowed separation of the effects of bulk aerosol and organics only. A hierarchical cluster analysis identified key compounds linked to OP, including yet unknown quinones, C₉H₆O₆ (an oxidation product of o-xylene), and C₉H₈O₄ (an oxidation product of trimethylbenzene), suggesting secondary products from aromatic precursors. We also found phthalic acid, a tracer for biomass burning and vehicular exhaust, and nitrosalicylic acid, an OP-enhancing compound. A volume-normalized OP of up to 4 nmol DTT min^-1 m^-3 was observed after metal removal, underscoring the importance of stable organic compounds and isolating metals to understand their relationship with OP in ambient particulate matter.

Increasing anthropogenic emissions have led to numerous organic compounds in the atmosphere, with uncertain effects on climate, ecosystems, and human health. Particularly, the composition and impact of organic aerosol in the upper troposphere and lower stratosphere (UTLS) remain poorly understood, with few studies addressing the general distribution of aerosols in this layer. In this work, we present a comprehensive analysis of a tropopause fold and convective systems during an airborne campaign over central Europe in summer 2024. We collected filter samples with a multichannel sampler for organic aerosol, effectively separating tropospheric and stratospheric air masses. As a result, we analyzed the chemical composition on a molecular level using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. A subsequent non-target analysis provides novel insights into compositional differences throughout the UTLS. Our findings reveal numerous anthropogenic organic compounds, including C8H19O5PS2 and C15H15NO3S2, alongside dicarboxylic acids, organosulfates, and oxidation products of volatile organic compounds found in stratospheric samples. Additional target analysis identifies pollutants like perfluorooctanoic acid and tris(2-chloropropyl) phosphate that redistribute from the ground. These findings underscore the importance of transport processes to high altitudes and the growing impact of anthropogenic pollution, contributing to a better understanding of the relationship between emissions, the chemical composition of the UTLS, and climate effects.

In this paper we introduce the new TropoPause Composition TOwed Sensor Shuttle (TPC-TOSS), which constitutes an advanced development of the AIRcraft TOwed Sensor Shuttle (AIRTOSS), introduced by Frey et al. (2009). As part of a tandem measurement platform with a Learjet 35A, both platforms were equipped with redundant instruments for co-located measurements of aerosol size distribution (Ultra-High Sensitivity Aerosol Spectrometer, UHSAS), ozone (2BTech model 205), cloud particles (Back-Scatter Cloud Probe, BCP), as well as relative humidity, temperature and pressure. To measure the exact position of the two platforms as well as the relative distance of the TPC-TOSS to the Learjet a Global Positioning System (GPS) is installed on both platforms. Two identical Inertial Navigation Systems (INS) further allow to monitor attitude angles (roll, pitch, and heading) and accelerations. Laboratory tests before and ground tests as well as in-flight tests during the intensive operation period show a good agreement of the ozone and temperature measurements of better than 4.2 ppbv +1.1 % (ozone) and 0.5 °C (temperature) at a noise level of ± (2 ppbv + 0.5 %) for 2 s data (ozone) and ± 0.1 K for 1 Hz data (temperature). Stability of the ozone monitor mounted in the TPC-TOSS has been tested and is estimated to be 2.2 ppbv (offset, 1σ) and 0.7 % (gain, 1σ), respectively, based on the drift of offset and gain during regular calibrations between measurement flights in the two weeks operation period. The new TPC-TOSS was successfully flown during the TPEx I (TropoPause composition gradients and mixing Experiment) mission in June 2024 and performed four flights covering the altitude range between 6.4 and 10.9 km. The tropopause was crossed several times as evident from different temperature and ozone gradients as well as gradients of the aerosol number concentration. With the setup we are able to resolve transient stability and composition gradients ranging from almost zero or even negative to strong positive gradients of up to 25 K km⁻¹ for potential temperature and from inverted to strong positive vertical gradients of ozone of up to 800 ppbv km⁻¹, respectively. These gradients are caused by transport and mixing due to convection or shear induced turbulence at the tropopause.

Increasing anthropogenic emissions have led to numerous organic compounds in the atmosphere, with uncertain effects on climate, ecosystems, and human health. Particularly, the composition and impact of organic aerosol in the upper troposphere and lower stratosphere (UTLS) remain poorly understood, with few studies addressing the general distribution of aerosols in this layer. In this work, we present a comprehensive analysis of a tropopause fold and convective systems during an airborne campaign over central Europe in summer 2024. We collected filter samples with a multichannel sampler for organic aerosol, effectively separating tropospheric and stratospheric air masses. As a result, we analyzed the chemical composition on a molecular level using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. A subsequent non-target analysis provides novel insights into compositional differences throughout the UTLS. Our findings reveal numerous anthropogenic organic compounds, including C₈H₁₉O₅PS₂ and C₁₅H₁₅NO₃S₂, alongside dicarboxylic acids, organosulfates, and oxidation products of volatile organic compounds found in stratospheric samples. Additional target analysis identifies pollutants like perfluorooctanoic acid and Tris(2-chloropropyl) phosphate that redistribute from the ground. These findings underscore the importance of transport processes to high altitudes and the growing impact of anthropogenic pollution, contributing to a better understanding of the relationship between emissions, the chemical composition of the UTLS, and climate effects.

Increasing anthropogenic emissions have led to numerous organic compounds in the atmosphere, with uncertain effects on climate, ecosystems, and human health. Particularly, the composition and impact of organic aerosol in the upper troposphere and lower stratosphere (UTLS) remain poorly understood, with few studies addressing the general distribution of aerosols in this layer. In this work, we present a comprehensive analysis of a tropopause fold and convective systems during an airborne campaign over central Europe in summer 2024. We collected filter samples with a multichannel sampler for organic aerosol, effectively separating tropospheric and stratospheric air masses. As a result, we analyzed the chemical composition on a molecular level using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. A subsequent non-target analysis provides novel insights into compositional differences throughout the UTLS. Our findings reveal numerous anthropogenic organic compounds, including C₈H₁₉O₅PS₂ and C₁₅H₁₅NO₃S₂, alongside dicarboxylic acids, organosulfates, and oxidation products of volatile organic compounds found in stratospheric samples. Additional target analysis identifies pollutants like perfluorooctanoic acid and Tris(2-chloropropyl) phosphate that redistribute from the ground. These findings underscore the importance of transport processes to high altitudes and the growing impact of anthropogenic pollution, contributing to a better understanding of the relationship between emissions, the chemical composition of the UTLS, and climate effects.

In this paper we introduce the new TropoPause Composition TOwed Sensor Shuttle (TPC-TOSS), which constitutes an advanced development of the AIRcraft TOwed Sensor Shuttle (AIRTOSS), introduced by Frey et al. (2009). As part of a tandem measurement platform with a Learjet 35A, both platforms were equipped with redundant instruments for collocated measurements of aerosol size distribution (Ultra-High Sensitivity Aerosol Spectrometer, UHSAS), ozone (2BTech model 205), cloud particles (Back-Scatter Cloud Probe, BCP), as well as relative humidity, temperature and pressure. To measure the exact position of the two platforms as well as the relative distance of the TPC-TOSS to the Learjet a Global Positioning System (GPS) is installed on both platforms. Two identical Inertial Navigation Systems (INS) further allow to monitor attitude angles (roll, pitch, and heading) and accelerations. Laboratory tests before and ground tests as well as inflight tests during the intensive operation period show a good agreement of the ozone and temperature measurements of better than 4.2 ppbv + 1.1 % (ozone) and 0.5 °C (temperature) at a noise level of ± (2 ppbv + 0.5 %) for 2 s data (ozone) and 0.1 K for 1 Hz data (temperature). Stability of the ozone monitor mounted in the TPC-TOSS has been tested and is estimated to be 2.2 ppbv (offset, 1 σ) and 0.7 % (gain, 1 σ), respectively, based on the drift of offset and gain during regular calibrations between measurement flights in the two weeks operation period. The new TPC-TOSS was successfully flown during the TPEx I (TropoPause composition gradients and mixing Experiment) mission in June 2024 and performed four flights covering the altitude range between 6 and 12 km. The tropopause was crossed several times as evident from different temperature and ozone gradients as well as gradients of the aerosol number density. With the setup we are able to resolve transient stability and composition gradients ranging from almost zero or even negative to strong positive gradients of up to 25 K km⁻¹ for potential temperature and from inverted to strong positive vertical gradients of ozone of up to 800 ppbv km⁻¹, respectively. These gradients are caused by transport and mixing due to convection or shear induced turbulence at the tropopause.

Increasing anthropogenic emissions have led to numerous organic compounds in the atmosphere, with uncertain effects on climate, ecosystems, and human health. Particularly, the composition and impact of organic aerosol in the upper troposphere and lower stratosphere (UTLS) remain poorly understood, with few studies addressing the general distribution of aerosols in this layer. In this work, we present a comprehensive analysis of a tropopause fold and convective systems during an airborne campaign over central Europe in summer 2024. We collected filter samples with a multichannel sampler for organic aerosol, effectively separating tropospheric and stratospheric air masses. As a result, we analyzed the chemical composition on a molecular level using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. A subsequent non-target analysis provides novel insights into compositional differences throughout the UTLS. Our findings reveal numerous anthropogenic organic compounds, including C₈H₁₉O₅PS₂ and C₁₅H₁₅NO₃S₂, alongside dicarboxylic acids, organosulfates, and oxidation products of volatile organic compounds found in stratospheric samples. Additional target analysis identifies pollutants like perfluorooctanoic acid and Tris(2-chloropropyl) phosphate that redistribute from the ground. These findings underscore the importance of transport processes to high altitudes and the growing impact of anthropogenic pollution, contributing to a better understanding of the relationship between emissions, the chemical composition of the UTLS, and climate effects.

Increasing anthropogenic emissions have led to numerous organic compounds in the atmosphere, with uncertain effects on climate, ecosystems, and human health. Particularly, the composition and impact of organic aerosol in the upper troposphere and lower stratosphere (UTLS) remain poorly understood, with few studies addressing the general distribution of aerosols in this layer. In this work, we present a comprehensive analysis of a tropopause fold and convective systems during an airborne campaign over central Europe in summer 2024. We collected filter samples with a multichannel sampler for organic aerosol, effectively separating tropospheric and stratospheric air masses. As a result, we analyzed the chemical composition on a molecular level using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. A subsequent non-target analysis provides novel insights into compositional differences throughout the UTLS. Our findings reveal numerous anthropogenic organic compounds, including C₈H₁₉O₅PS₂ and C₁₅H₁₅NO₃S₂, alongside dicarboxylic acids, organosulfates, and oxidation products of volatile organic compounds found in stratospheric samples. Additional target analysis identifies pollutants like perfluorooctanoic acid and Tris(2-chloropropyl) phosphate that redistribute from the ground. These findings underscore the importance of transport processes to high altitudes and the growing impact of anthropogenic pollution, contributing to a better understanding of the relationship between emissions, the chemical composition of the UTLS, and climate effects.