Pub Date : 2024-06-26DOI: 10.5194/egusphere-2024-1848
Feng Jiang, Harald Saathoff, Junwei Song, Hengheng Zhang, Linyu Gao, Thomas Leisner
Abstract. Brown carbon aerosol (BrC) is one major contributor to atmospheric air pollution in Europe, especially in winter. Therefore, we studied the chemical composition, diurnal variation, and sources of BrC from 17th February to 16th March at a rural location in southwest Germany. In total, 178 potential BrC molecules (including 7 nitro aromatic compounds, NACs) were identified in the particle phase comprising on average 63 ± 32 ng m−3, and 31 potential BrC (including 4 NACs) molecules were identified in the gas phase contributing on average 6.2 ± 5.0 ng m−3 during the whole campaign. The 178 potential BrC molecules only accounted for 2.3 ± 1.5 % of the total organic mass, but can explain 11 ± 11 % of the total BrC absorption at 370 nm, assuming an average mass absorption coefficient at 370 nm (MAC370) of 9.5 m2 g−1. A few BrC molecules dominated the total BrC absorption. In addition, diurnal variations show that gas phase BrC was higher at daytime and lower at night. It was mainly controlled by secondary formation (e.g. photooxidation) and particle-to-gas partitioning. Correspondingly, the particle phase BrC was lower at daytime and higher at nighttime. Secondary formation dominates the particle-phase BrC with 61 ± 21 %, while 39 ± 21 % originated from biomass burning. Furthermore, the particle-phase BrC showed decreasing light absorption due to photochemical aging. This study extends the current understanding of real-time behaviors of brown carbon aerosol in the gas and particle phase at a location characteristic for the central Europe.
{"title":"Brown carbon aerosol in rural Germany: sources, chemistry, and diurnal variations","authors":"Feng Jiang, Harald Saathoff, Junwei Song, Hengheng Zhang, Linyu Gao, Thomas Leisner","doi":"10.5194/egusphere-2024-1848","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1848","url":null,"abstract":"<strong>Abstract.</strong> Brown carbon aerosol (BrC) is one major contributor to atmospheric air pollution in Europe, especially in winter. Therefore, we studied the chemical composition, diurnal variation, and sources of BrC from 17<sup>th</sup> February to 16<sup>th</sup> March at a rural location in southwest Germany. In total, 178 potential BrC molecules (including 7 nitro aromatic compounds, NACs) were identified in the particle phase comprising on average 63 ± 32 ng m<sup>−3</sup>, and 31 potential BrC (including 4 NACs) molecules were identified in the gas phase contributing on average 6.2 ± 5.0 ng m<sup>−3</sup> during the whole campaign. The 178 potential BrC molecules only accounted for 2.3 ± 1.5 % of the total organic mass, but can explain 11 ± 11 % of the total BrC absorption at 370 nm, assuming an average mass absorption coefficient at 370 nm (MAC<sub>370</sub>) of 9.5 m<sup>2</sup> g<sup>−1</sup>. A few BrC molecules dominated the total BrC absorption. In addition, diurnal variations show that gas phase BrC was higher at daytime and lower at night. It was mainly controlled by secondary formation (e.g. photooxidation) and particle-to-gas partitioning. Correspondingly, the particle phase BrC was lower at daytime and higher at nighttime. Secondary formation dominates the particle-phase BrC with 61 ± 21 %, while 39 ± 21 % originated from biomass burning. Furthermore, the particle-phase BrC showed decreasing light absorption due to photochemical aging. This study extends the current understanding of real-time behaviors of brown carbon aerosol in the gas and particle phase at a location characteristic for the central Europe.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-26DOI: 10.5194/acp-24-7309-2024
Haklim Choi, Alison L. Redington, Hyeri Park, Jooil Kim, Rona L. Thompson, Jens Mühle, Peter K. Salameh, Christina M. Harth, Ray F. Weiss, Alistair J. Manning, Sunyoung Park
Abstract. Hydrofluorocarbons (HFCs) are powerful anthropogenic greenhouse gases (GHGs) with high global-warming potentials (GWPs). They have been widely used as refrigerants, insulation foam-blowing agents, aerosol propellants, and fire suppression agents. Since the mid-1990s, emissions of HFCs have been increasing rapidly as they are used in many applications to replace ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) whose consumption and production have been phased out under the Montreal Protocol (MP). Due to the high GWP of HFCs, the Kigali Amendment to the MP requires the phasedown of production and consumption of HFCs to gradually achieve an 80 %–85 % reduction by 2047, starting in 2019 for non-Article 5 (developed) countries with a 10 % reduction against each defined baseline and later schedules for Article 5 (developing) countries. In this study, we have examined long-term high-precision measurements of atmospheric abundances of five major HFCs (HFC-134a, HFC-143a, HFC-32, HFC-125, and HFC-152a) at Gosan station, Jeju Island, South Korea, from 2008 to 2020. Background abundances of HFCs gradually increased, and the inflow of polluted air masses with elevated abundances from surrounding source regions were detected over the entire period. From these pollution events, we inferred regional and country-specific HFC emission estimates using two independent Lagrangian particle dispersion models and Bayesian inversion frameworks (FLEXPART-FLEXINVERT+ and NAME-InTEM). The spatial distribution of the derived “top-down” (measurement based) emissions for all HFCs shows large fluxes from megacities and industrial areas in the region. Our most important finding is that HFC emissions in eastern China and Japan have sharply increased from 2016 to 2018. The contribution of East Asian HFC emissions to the global total increased from 9 % (2008–2014) to 13 % (2016–2020). In particular, HFC emissions in Japan (Annex I country) rose rapidly from 2016 onward, with accumulated total inferred HFC emissions being ∼ 114 Gg yr−1, which is ∼ 76 Gg yr−1 higher for 2016–2020 than the “bottom-up” (i.e., based on activity data and emission factors) emissions of ∼ 38 Gg yr−1 reported to the United Nations Framework Convention on Climate Change (UNFCCC). This is likely related to the increase in domestic demand in Japan for refrigerants and air-conditioning-system-related products and incomplete accounting. A downward trend of HFC emissions that started in 2019 reflects the effectiveness of the F-gas policy in Japan. Eastern China and South Korea, though not obligated to report to the UNFCCC, voluntarily reported emissions, which also show differences between top-down and bottom-up emission estimates, demonstrating the need for atmospheric measurements, comprehensive data analysis, and accurate reporting for precise emission management. Further, the proportional contribution of each country's CO2-equivalent HFC emissions has changed over tim
{"title":"Revealing the significant acceleration of hydrofluorocarbon (HFC) emissions in eastern Asia through long-term atmospheric observations","authors":"Haklim Choi, Alison L. Redington, Hyeri Park, Jooil Kim, Rona L. Thompson, Jens Mühle, Peter K. Salameh, Christina M. Harth, Ray F. Weiss, Alistair J. Manning, Sunyoung Park","doi":"10.5194/acp-24-7309-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7309-2024","url":null,"abstract":"Abstract. Hydrofluorocarbons (HFCs) are powerful anthropogenic greenhouse gases (GHGs) with high global-warming potentials (GWPs). They have been widely used as refrigerants, insulation foam-blowing agents, aerosol propellants, and fire suppression agents. Since the mid-1990s, emissions of HFCs have been increasing rapidly as they are used in many applications to replace ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) whose consumption and production have been phased out under the Montreal Protocol (MP). Due to the high GWP of HFCs, the Kigali Amendment to the MP requires the phasedown of production and consumption of HFCs to gradually achieve an 80 %–85 % reduction by 2047, starting in 2019 for non-Article 5 (developed) countries with a 10 % reduction against each defined baseline and later schedules for Article 5 (developing) countries. In this study, we have examined long-term high-precision measurements of atmospheric abundances of five major HFCs (HFC-134a, HFC-143a, HFC-32, HFC-125, and HFC-152a) at Gosan station, Jeju Island, South Korea, from 2008 to 2020. Background abundances of HFCs gradually increased, and the inflow of polluted air masses with elevated abundances from surrounding source regions were detected over the entire period. From these pollution events, we inferred regional and country-specific HFC emission estimates using two independent Lagrangian particle dispersion models and Bayesian inversion frameworks (FLEXPART-FLEXINVERT+ and NAME-InTEM). The spatial distribution of the derived “top-down” (measurement based) emissions for all HFCs shows large fluxes from megacities and industrial areas in the region. Our most important finding is that HFC emissions in eastern China and Japan have sharply increased from 2016 to 2018. The contribution of East Asian HFC emissions to the global total increased from 9 % (2008–2014) to 13 % (2016–2020). In particular, HFC emissions in Japan (Annex I country) rose rapidly from 2016 onward, with accumulated total inferred HFC emissions being ∼ 114 Gg yr−1, which is ∼ 76 Gg yr−1 higher for 2016–2020 than the “bottom-up” (i.e., based on activity data and emission factors) emissions of ∼ 38 Gg yr−1 reported to the United Nations Framework Convention on Climate Change (UNFCCC). This is likely related to the increase in domestic demand in Japan for refrigerants and air-conditioning-system-related products and incomplete accounting. A downward trend of HFC emissions that started in 2019 reflects the effectiveness of the F-gas policy in Japan. Eastern China and South Korea, though not obligated to report to the UNFCCC, voluntarily reported emissions, which also show differences between top-down and bottom-up emission estimates, demonstrating the need for atmospheric measurements, comprehensive data analysis, and accurate reporting for precise emission management. Further, the proportional contribution of each country's CO2-equivalent HFC emissions has changed over tim","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The capacity of particulate matter (PM) to generate reactive oxygen species (ROS) in vivo leading to oxidative stress is thought to be a main pathway in the health effects of PM inhalation. Exogenous ROS from PM can be assessed by acellular oxidative potential (OP) measurements as a proxy of the induction of oxidative stress in the lungs. Here, we investigate the importance of OP apportionment methods for OP distribution by PM10 sources in different types of environments. PM10 sources derived from receptor models (e.g., EPA positive matrix factorization (EPA PMF)) are coupled with regression models expressing the associations between PM10 sources and PM10 OP measured by ascorbic acid (OPAA) and dithiothreitol assay (OPDTT). These relationships are compared for eight regression techniques: ordinary least squares, weighted least squares, positive least squares, Ridge, Lasso, generalized linear model, random forest, and multilayer perceptron. The models are evaluated on 1 year of PM10 samples and chemical analyses at each of six sites of different typologies in France to assess the possible impact of PM source variability on PM10 OP apportionment. PM10 source-specific OPDTT and OPAA and out-of-sample apportionment accuracy vary substantially by model, highlighting the importance of model selection according to the datasets. Recommendations for the selection of the most accurate model are provided, encompassing considerations such as multicollinearity and homoscedasticity.
摘要颗粒物（PM）在体内产生活性氧（ROS）导致氧化应激的能力被认为是吸入颗粒物影响健康的主要途径。可吸入颗粒物产生的外源性 ROS 可通过细胞氧化电位（OP）测量来评估，以此作为肺部氧化应激诱导的替代物。在这里，我们研究了不同类型环境中 PM10 来源的 OP 分布的 OP 分摊方法的重要性。从受体模型（如 EPA 正矩阵因式分解（EPA PMF））得出的 PM10 来源与表达 PM10 来源与通过抗坏血酸（OPAA）和二硫苏糖醇测定法（OPDTT）测量的 PM10 OP 之间关系的回归模型相结合。这些关系通过八种回归技术进行了比较：普通最小二乘法、加权最小二乘法、正最小二乘法、Ridge、Lasso、广义线性模型、随机森林和多层感知器。这些模型对法国六个不同类型地点的一年 PM10 样品和化学分析进行了评估，以评估 PM10 源变异性对 PM10 OP 分配可能产生的影响。不同模型的PM10特定源OPDTT和OPAA以及样本外分摊的准确性差异很大，这突出了根据数据集选择模型的重要性。提供了选择最准确模型的建议，包括多共线性和同方差等考虑因素。
{"title":"Unveiling the optimal regression model for source apportionment of the oxidative potential of PM10","authors":"Vy Dinh Ngoc Thuy, Jean-Luc Jaffrezo, Ian Hough, Pamela A. Dominutti, Guillaume Salque Moreton, Grégory Gille, Florie Francony, Arabelle Patron-Anquez, Olivier Favez, Gaëlle Uzu","doi":"10.5194/acp-24-7261-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7261-2024","url":null,"abstract":"Abstract. The capacity of particulate matter (PM) to generate reactive oxygen species (ROS) in vivo leading to oxidative stress is thought to be a main pathway in the health effects of PM inhalation. Exogenous ROS from PM can be assessed by acellular oxidative potential (OP) measurements as a proxy of the induction of oxidative stress in the lungs. Here, we investigate the importance of OP apportionment methods for OP distribution by PM10 sources in different types of environments. PM10 sources derived from receptor models (e.g., EPA positive matrix factorization (EPA PMF)) are coupled with regression models expressing the associations between PM10 sources and PM10 OP measured by ascorbic acid (OPAA) and dithiothreitol assay (OPDTT). These relationships are compared for eight regression techniques: ordinary least squares, weighted least squares, positive least squares, Ridge, Lasso, generalized linear model, random forest, and multilayer perceptron. The models are evaluated on 1 year of PM10 samples and chemical analyses at each of six sites of different typologies in France to assess the possible impact of PM source variability on PM10 OP apportionment. PM10 source-specific OPDTT and OPAA and out-of-sample apportionment accuracy vary substantially by model, highlighting the importance of model selection according to the datasets. Recommendations for the selection of the most accurate model are provided, encompassing considerations such as multicollinearity and homoscedasticity.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-26DOI: 10.5194/acp-24-7283-2024
Donatello Gallucci, Domenico Cimini, Emma Turner, Stuart Fox, Philip W. Rosenkranz, Mikhail Y. Tretyakov, Vinia Mattioli, Salvatore Larosa, Filomena Romano
Abstract. Atmospheric radiative transfer models are extensively used in Earth observation to simulate radiative processes occurring in the atmosphere and to provide both upwelling and downwelling synthetic brightness temperatures for ground-based, airborne, and satellite radiometric sensors. For a meaningful comparison between simulated and observed radiances, it is crucial to characterize the uncertainty in such models. The purpose of this work is to quantify the uncertainty in radiative transfer models due to uncertainty in the associated spectroscopic parameters and to compute simulated brightness temperature uncertainties for millimeter- and submillimeter-wave channels of downward-looking satellite radiometric sensors (MicroWave Imager, MWI; Ice Cloud Imager, ICI; MicroWave Sounder, MWS; and Advanced Technology Microwave Sounder, ATMS) as well as upward-looking airborne radiometers (International Submillimetre Airborne Radiometer, ISMAR, and Microwave Airborne Radiometer Scanning System, MARSS). The approach adopted here is firstly to study the sensitivity of brightness temperature calculations to each spectroscopic parameter separately, then to identify the dominant parameters and investigate their uncertainty covariance, and finally to compute the total brightness temperature uncertainty due to the full uncertainty covariance matrix for the identified set of relevant spectroscopic parameters. The approach is applied to a recent version of the Millimeter-wave Propagation Model, taking into account water vapor, oxygen, and ozone spectroscopic parameters, though the approach is general and can be applied to any radiative transfer code. A set of 135 spectroscopic parameters were identified as dominant for the uncertainty in simulated brightness temperatures (26 for water vapor, 109 for oxygen, none for ozone). The uncertainty in simulated brightness temperatures is computed for six climatology conditions (ranging from sub-Arctic winter to tropical) and all instrument channels. Uncertainty is found to be up to few kelvins [K] in the millimeter-wave range, whereas it is considerably lower in the submillimeter-wave range (less than 1 K).
{"title":"Uncertainty in simulated brightness temperature due to sensitivity to atmospheric gas spectroscopic parameters from the centimeter- to submillimeter-wave range","authors":"Donatello Gallucci, Domenico Cimini, Emma Turner, Stuart Fox, Philip W. Rosenkranz, Mikhail Y. Tretyakov, Vinia Mattioli, Salvatore Larosa, Filomena Romano","doi":"10.5194/acp-24-7283-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7283-2024","url":null,"abstract":"Abstract. Atmospheric radiative transfer models are extensively used in Earth observation to simulate radiative processes occurring in the atmosphere and to provide both upwelling and downwelling synthetic brightness temperatures for ground-based, airborne, and satellite radiometric sensors. For a meaningful comparison between simulated and observed radiances, it is crucial to characterize the uncertainty in such models. The purpose of this work is to quantify the uncertainty in radiative transfer models due to uncertainty in the associated spectroscopic parameters and to compute simulated brightness temperature uncertainties for millimeter- and submillimeter-wave channels of downward-looking satellite radiometric sensors (MicroWave Imager, MWI; Ice Cloud Imager, ICI; MicroWave Sounder, MWS; and Advanced Technology Microwave Sounder, ATMS) as well as upward-looking airborne radiometers (International Submillimetre Airborne Radiometer, ISMAR, and Microwave Airborne Radiometer Scanning System, MARSS). The approach adopted here is firstly to study the sensitivity of brightness temperature calculations to each spectroscopic parameter separately, then to identify the dominant parameters and investigate their uncertainty covariance, and finally to compute the total brightness temperature uncertainty due to the full uncertainty covariance matrix for the identified set of relevant spectroscopic parameters. The approach is applied to a recent version of the Millimeter-wave Propagation Model, taking into account water vapor, oxygen, and ozone spectroscopic parameters, though the approach is general and can be applied to any radiative transfer code. A set of 135 spectroscopic parameters were identified as dominant for the uncertainty in simulated brightness temperatures (26 for water vapor, 109 for oxygen, none for ozone). The uncertainty in simulated brightness temperatures is computed for six climatology conditions (ranging from sub-Arctic winter to tropical) and all instrument channels. Uncertainty is found to be up to few kelvins [K] in the millimeter-wave range, whereas it is considerably lower in the submillimeter-wave range (less than 1 K).","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/egusphere-2024-1880
Rui Jin, Wei Hu, Peimin Duan, Ming Sheng, Dandan Liu, Ziye Huang, Mutong Niu, Libin Wu, Junjun Deng, Pingqing Fu
Abstract. The interactions of metabolically active atmospheric microorganisms with cloud organic matter can alter the atmospheric carbon cycle. Upon deposition, atmospheric microorganisms can influence microbial communities in surface Earth systems. However, the metabolic activities of cultivable atmospheric microorganisms in settled habitats remain less understood. Here, we investigated exometabolites produced by typical bacterial and fungal species isolated from the urban atmosphere to elucidate their biogeochemical roles. Molecular compositions of exometabolites were analyzed using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry. Annotation through the Kyoto Encyclopedia of Genes and Genomes database helped identify metabolic processes. Results showed that bacterial and fungal strains produce exometabolites with lower H/C and higher O/C ratios than consumed and resistant compounds. CHON compounds constituted over 50 % of the identified formulas of exometabolites. Bacterial exometabolites contained more abundant CHONS compounds (25.2 %), while fungal exometabolites were rich in CHO compounds (31.7 %). These microbial exometabolites predominantly comprised aliphatic/peptide-like and carboxyl-rich alicyclic molecules (CRAM-like). Significant variations in metabolites were observed among different strains. Bacteria showed a performance for amino acid synthesis, while fungi were more active in transcription and expression processes. Lipid metabolism, amino acid metabolism, and carbohydrate metabolism varied widely among bacterial strains, while fungi exhibited marked differences in carbohydrate metabolism and secondary metabolism. This comprehensive examination of metabolite characteristics at the molecular level for typical culturable airborne microorganisms enhances our understanding of their potential metabolic activities at air-land/water interfaces. These insights are pivotal for assessing the biogeochemical impacts of atmospheric microorganisms following their deposition.
摘要代谢活跃的大气微生物与云层有机物的相互作用可改变大气碳循环。大气微生物在沉积后会影响地球表面系统中的微生物群落。然而，人们对定居栖息地中可培养的大气微生物的代谢活动仍然知之甚少。在这里，我们研究了从城市大气中分离出来的典型细菌和真菌物种产生的外代谢产物，以阐明它们的生物地球化学作用。我们使用超高分辨率傅立叶变换离子回旋共振质谱分析了外代谢物的分子组成。通过京都基因和基因组百科全书数据库进行注释，有助于确定代谢过程。结果表明，细菌和真菌菌株产生的外代谢物与消耗性和抗性化合物相比，H/C 比值较低，O/C 比值较高。在已鉴定的外代谢物配方中，CHON化合物占了50%以上。细菌外代谢物含有更多的 CHONS 化合物（25.2%），而真菌外代谢物则富含 CHO 化合物（31.7%）。这些微生物外代谢物主要包括脂肪族/肽类和富含羧基的脂环族分子（CRAM-like）。不同菌株的代谢物存在显著差异。细菌在氨基酸合成方面表现突出，而真菌在转录和表达过程中更为活跃。细菌菌株之间的脂质代谢、氨基酸代谢和碳水化合物代谢差异很大，而真菌在碳水化合物代谢和次级代谢方面表现出明显差异。对典型的可培养空气传播微生物的代谢物特征进行分子水平的全面研究，加深了我们对它们在空气-陆地-水界面的潜在代谢活动的了解。这些见解对于评估大气微生物沉积后的生物地球化学影响至关重要。
{"title":"Exometabolomic exploration of culturable airborne microorganisms from an urban atmosphere","authors":"Rui Jin, Wei Hu, Peimin Duan, Ming Sheng, Dandan Liu, Ziye Huang, Mutong Niu, Libin Wu, Junjun Deng, Pingqing Fu","doi":"10.5194/egusphere-2024-1880","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1880","url":null,"abstract":"<strong>Abstract.</strong> The interactions of metabolically active atmospheric microorganisms with cloud organic matter can alter the atmospheric carbon cycle. Upon deposition, atmospheric microorganisms can influence microbial communities in surface Earth systems. However, the metabolic activities of cultivable atmospheric microorganisms in settled habitats remain less understood. Here, we investigated exometabolites produced by typical bacterial and fungal species isolated from the urban atmosphere to elucidate their biogeochemical roles. Molecular compositions of exometabolites were analyzed using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry. Annotation through the Kyoto Encyclopedia of Genes and Genomes database helped identify metabolic processes. Results showed that bacterial and fungal strains produce exometabolites with lower H/C and higher O/C ratios than consumed and resistant compounds. CHON compounds constituted over 50 % of the identified formulas of exometabolites. Bacterial exometabolites contained more abundant CHONS compounds (25.2 %), while fungal exometabolites were rich in CHO compounds (31.7 %). These microbial exometabolites predominantly comprised aliphatic/peptide-like and carboxyl-rich alicyclic molecules (CRAM-like). Significant variations in metabolites were observed among different strains. Bacteria showed a performance for amino acid synthesis, while fungi were more active in transcription and expression processes. Lipid metabolism, amino acid metabolism, and carbohydrate metabolism varied widely among bacterial strains, while fungi exhibited marked differences in carbohydrate metabolism and secondary metabolism. This comprehensive examination of metabolite characteristics at the molecular level for typical culturable airborne microorganisms enhances our understanding of their potential metabolic activities at air-land/water interfaces. These insights are pivotal for assessing the biogeochemical impacts of atmospheric microorganisms following their deposition.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/acp-24-7227-2024
Zhen Liu, Massimo A. Bollasina, Laura J. Wilcox
Abstract. Reliable attribution of Asian summer monsoon variations to aerosol forcing is critical to reducing uncertainties in future projections of regional water availability, which is of utmost importance for risk management and adaptation planning in this densely populated region. Yet, simulating the monsoon remains a challenge for climate models that suffer from long-standing biases, undermining their reliability in attributing anthropogenically forced changes. We analyze a suite of climate model experiments to identify a link between model biases and monsoon responses to Asian aerosols and associated physical mechanisms, including the role of large-scale circulation changes. The aerosol impact on monsoon precipitation and circulation is strongly influenced by a model's ability to simulate the spatio-temporal variability in the climatological monsoon winds, clouds, and precipitation across Asia, which modulates the magnitude and efficacy of aerosol–cloud–precipitation interactions, an important component of the total aerosol response. There is a strong interplay between South Asia and East Asia monsoon precipitation biases and their relative predominance in driving the overall monsoon response. We found a striking contrast between the early- and late-summer aerosol-driven changes ascribable to opposite signs and seasonal evolution of the biases in the two regions. A realistic simulation of the evolution of the large-scale atmospheric circulation is crucial to realize the full extent of the aerosol impact over Asia. These findings provide important implications for better understanding and constraining the diversity and inconsistencies of model responses to aerosol changes over Asia in historical simulations and future projections.
{"title":"Impact of Asian aerosols on the summer monsoon strongly modulated by regional precipitation biases","authors":"Zhen Liu, Massimo A. Bollasina, Laura J. Wilcox","doi":"10.5194/acp-24-7227-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7227-2024","url":null,"abstract":"Abstract. Reliable attribution of Asian summer monsoon variations to aerosol forcing is critical to reducing uncertainties in future projections of regional water availability, which is of utmost importance for risk management and adaptation planning in this densely populated region. Yet, simulating the monsoon remains a challenge for climate models that suffer from long-standing biases, undermining their reliability in attributing anthropogenically forced changes. We analyze a suite of climate model experiments to identify a link between model biases and monsoon responses to Asian aerosols and associated physical mechanisms, including the role of large-scale circulation changes. The aerosol impact on monsoon precipitation and circulation is strongly influenced by a model's ability to simulate the spatio-temporal variability in the climatological monsoon winds, clouds, and precipitation across Asia, which modulates the magnitude and efficacy of aerosol–cloud–precipitation interactions, an important component of the total aerosol response. There is a strong interplay between South Asia and East Asia monsoon precipitation biases and their relative predominance in driving the overall monsoon response. We found a striking contrast between the early- and late-summer aerosol-driven changes ascribable to opposite signs and seasonal evolution of the biases in the two regions. A realistic simulation of the evolution of the large-scale atmospheric circulation is crucial to realize the full extent of the aerosol impact over Asia. These findings provide important implications for better understanding and constraining the diversity and inconsistencies of model responses to aerosol changes over Asia in historical simulations and future projections.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Urban Green Spaces (UGS) are widely advocated for mitigating urban atmospheric environment. However, this study reveals that it can exacerbate urban ozone (O3) levels under certain conditions, as demonstrated by a September 2017 study in Guangzhou, China. Utilizing the Weather Research and Forecasting Model with the Model of Emissions of Gases and Aerosols from Nature (WRF-MEGAN) and the Community Multiscale Air Quality (CMAQ) model with a high horizontal resolution (1 km), we assessed the impact of UGS-related biogenic volatile organic compound (BVOC) emissions on urban O3. Our findings indicate that UGS-BVOC emissions in Guangzhou amounted to 666.49 Gg, primarily from isoprene (ISOP) and terpenes (TERP). These emissions contribute ~30 % of urban ISOP concentrations and their incorporations to the model significantly reduce the underestimation against observations. The study shows improvements in simulation biases for NO2, from 7.01 µg/m3 to 6.03 µg/m3, and for O3, from 7.77 µg/m3 to -1.60 µg/m3. UGS-BVOC and UGS-LUCC (land use cover changes) integration in air quality models notably enhances surface monthly mean O3 predictions by 3.6–8.0 µg/m3 (+3.8–8.5 %) and contributes up to 18.7 µg/m3 (+10.0 %) to MDA8 O3 during O3 pollution episodes. Additionally, UGS-BVOC emissions alone increase the monthly mean O3 levels by 2.2–3.0 µg/m3 (+2.3–3.2 %) in urban areas and contribute up to 6.3 µg/m3 (+3.3 %) to MDA8 O3 levels during O3 pollution episodes. These impacts can extend to surrounding suburban and rural areas through regional transport, highlighting the need for selecting low-emission vegetation and refining vegetation classification in urban planning.
{"title":"Unheralded contributions of biogenic volatile organic compounds from urban greening to ozone pollution: a high-resolution modeling study","authors":"Haofan Wang, Yuejin Li, Yiming Liu, Xiao Lu, Yang Zhang, Qi Fan, Tianhang Zhang, Chong Shen","doi":"10.5194/egusphere-2024-1163","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1163","url":null,"abstract":"<strong>Abstract.</strong> Urban Green Spaces (UGS) are widely advocated for mitigating urban atmospheric environment. However, this study reveals that it can exacerbate urban ozone (O<sub>3</sub>) levels under certain conditions, as demonstrated by a September 2017 study in Guangzhou, China. Utilizing the Weather Research and Forecasting Model with the Model of Emissions of Gases and Aerosols from Nature (WRF-MEGAN) and the Community Multiscale Air Quality (CMAQ) model with a high horizontal resolution (1 km), we assessed the impact of UGS-related biogenic volatile organic compound (BVOC) emissions on urban O<sub>3</sub>. Our findings indicate that UGS-BVOC emissions in Guangzhou amounted to 666.49 Gg, primarily from isoprene (ISOP) and terpenes (TERP). These emissions contribute ~30 % of urban ISOP concentrations and their incorporations to the model significantly reduce the underestimation against observations. The study shows improvements in simulation biases for NO<sub>2</sub>, from 7.01 µg/m<sup>3</sup> to 6.03 µg/m<sup>3</sup>, and for O<sub>3</sub>, from 7.77 µg/m<sup>3</sup> to -1.60 µg/m<sup>3</sup>. UGS-BVOC and UGS-LUCC (land use cover changes) integration in air quality models notably enhances surface monthly mean O<sub>3</sub> predictions by 3.6–8.0 µg/m<sup>3 </sup>(+3.8–8.5 %) and contributes up to 18.7 µg/m<sup>3 </sup>(+10.0 %) to MDA8 O<sub>3</sub> during O<sub>3</sub> pollution episodes. Additionally, UGS-BVOC emissions alone increase the monthly mean O<sub>3</sub> levels by 2.2–3.0 µg/m<sup>3 </sup>(+2.3–3.2 %) in urban areas and contribute up to 6.3 µg/m<sup>3 </sup>(+3.3 %) to MDA8 O<sub>3</sub> levels during O<sub>3</sub> pollution episodes. These impacts can extend to surrounding suburban and rural areas through regional transport, highlighting the need for selecting low-emission vegetation and refining vegetation classification in urban planning.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/egusphere-2024-1851
Julika Zinke, Gabriel Freitas, Rachel Ann Foster, Paul Zieger, Ernst Douglas Nilsson, Piotr Markuszewski, Matthew Edward Salter
Abstract. Primary biological aerosol particles (PBAP) can influence climate and affect human health. To investigate the aerosolization of PBAP with sea spray aerosol (SSA), we conducted ship-based campaigns in the central Baltic Sea near Östergarnsholm in May and August 2021. Using a plunging jet sea spray simulation chamber filled with local seawater, we performed controlled chamber experiments to collect filters and measure aerosols. We determined the abundance of bacteria in the chamber air and seawater by staining and fluorescence microscopy, normalizing these values to sodium concentration to calculate enrichment factors. Our results showed that bacteria were enriched in the aerosol by 13 to 488 times compared to the underlying seawater, with no significant enrichment observed in the sea surface microlayer. Bacterial abundances obtained through microscopy were compared with estimates of fluorescent PBAP (fPBAP) using a single-particle fluorescence spectrometer. We estimated bacterial emission fluxes using two independent approaches: (1) applying the enrichment factors derived from this study with mass flux estimates from previous SSA parameterizations, and (2) using a scaling approach from a companion study. Both methods produced bacterial emission flux estimates that were in good agreement and on the same order of magnitude as previous studies, while fPBAP emission flux estimates were significantly lower. Furthermore, 16S rRNA sequencing identified the diversity of bacteria enriched in the nascent SSA compared to the underlying seawater.
{"title":"Quantification and characterization of primary biological aerosol particles and bacteria aerosolized from Baltic seawater","authors":"Julika Zinke, Gabriel Freitas, Rachel Ann Foster, Paul Zieger, Ernst Douglas Nilsson, Piotr Markuszewski, Matthew Edward Salter","doi":"10.5194/egusphere-2024-1851","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1851","url":null,"abstract":"<strong>Abstract.</strong> Primary biological aerosol particles (PBAP) can influence climate and affect human health. To investigate the aerosolization of PBAP with sea spray aerosol (SSA), we conducted ship-based campaigns in the central Baltic Sea near Östergarnsholm in May and August 2021. Using a plunging jet sea spray simulation chamber filled with local seawater, we performed controlled chamber experiments to collect filters and measure aerosols. We determined the abundance of bacteria in the chamber air and seawater by staining and fluorescence microscopy, normalizing these values to sodium concentration to calculate enrichment factors. Our results showed that bacteria were enriched in the aerosol by 13 to 488 times compared to the underlying seawater, with no significant enrichment observed in the sea surface microlayer. Bacterial abundances obtained through microscopy were compared with estimates of fluorescent PBAP (fPBAP) using a single-particle fluorescence spectrometer. We estimated bacterial emission fluxes using two independent approaches: (1) applying the enrichment factors derived from this study with mass flux estimates from previous SSA parameterizations, and (2) using a scaling approach from a companion study. Both methods produced bacterial emission flux estimates that were in good agreement and on the same order of magnitude as previous studies, while fPBAP emission flux estimates were significantly lower. Furthermore, 16S rRNA sequencing identified the diversity of bacteria enriched in the nascent SSA compared to the underlying seawater.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.5194/acp-24-7253-2024
Naser Mahfouz, Johannes Mülmenstädt, Susannah Burrows
Abstract. Cloud albedo susceptibility to droplet number perturbation remains a source of uncertainty in understanding aerosol–cloud interactions and thus both past and present climate states. Through the Energy Exascale Earth System Model (E3SM) v2 experiments, we probe the effects of competing processes on cloud albedo susceptibility of low-lying marine stratocumulus in the northeast Pacific. In present-day conditions, we find that increasing precipitation suppression by aerosols increases cloud albedo susceptibility, whereas increasing cloud sedimentation decreases it. By constructing a hypothetical model configuration exhibiting negative susceptibility under all conditions, we conclude that cloud albedo change due to aerosol perturbation cannot be predicted by present-day co-variabilities in E3SM v2. As such, our null result herein challenges the assumption that present-day climate observations are sufficient to constrain past states, at least in the context of cloud albedo changes to aerosol perturbation.
{"title":"Present-day correlations are insufficient to predict cloud albedo change by anthropogenic aerosols in E3SM v2","authors":"Naser Mahfouz, Johannes Mülmenstädt, Susannah Burrows","doi":"10.5194/acp-24-7253-2024","DOIUrl":"https://doi.org/10.5194/acp-24-7253-2024","url":null,"abstract":"Abstract. Cloud albedo susceptibility to droplet number perturbation remains a source of uncertainty in understanding aerosol–cloud interactions and thus both past and present climate states. Through the Energy Exascale Earth System Model (E3SM) v2 experiments, we probe the effects of competing processes on cloud albedo susceptibility of low-lying marine stratocumulus in the northeast Pacific. In present-day conditions, we find that increasing precipitation suppression by aerosols increases cloud albedo susceptibility, whereas increasing cloud sedimentation decreases it. By constructing a hypothetical model configuration exhibiting negative susceptibility under all conditions, we conclude that cloud albedo change due to aerosol perturbation cannot be predicted by present-day co-variabilities in E3SM v2. As such, our null result herein challenges the assumption that present-day climate observations are sufficient to constrain past states, at least in the context of cloud albedo changes to aerosol perturbation.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Aerosol phase state is crucial for air quality, climate, and human health. Atmospheric secondary aerosols are often internally mixed with organic and inorganic components, particularly dicarboxylic acids, ammonium, sulfate, nitrate, and chloride. These complex compositions enable aqueous reaction between organic and inorganic species, significantly complicating aerosol phase behaviour during aging and making phase predictions challenging. We investigated carboxylate/ammonium salt mixtures using in-situ infrared spectroscopy. The di- and tri- carboxylates included sodium pyruvate (SP), sodium tartrate (ST), and sodium citrate (SC), while the ammonium salts included NH4NO3, NH4Cl, and (NH4)2SO4. Our results demonstrated that aqueous replacement reactions between carboxylates and ammonium salts was promoted by the formation and depletion of NH3 as relative humidity (RH) changed. Solid NaNO3, SP, and Na2SO4 formed in SP/ammonium aerosol at 35.7 %~12.7 %, 64 % and 65.5 %~60.1 % RH, respectively. In contrast, reactions between ST or SC and (NH4)2SO4 was incomplete due to the gel structure of SC or ST at low RH. Upon hydration, the deliquescence RH of Na2SO4 in SP/(NH4)2SO4 (88.8 %–95.2 %) and NaNO3 in SP/NH4NO3 (76.5–81.9 %) are higher than those of pure inorganic aerosols. Unexpectedly, aqueous Na2SO4 crystallized upon humidification in ST/(NH4)2SO4 particles at 43.6 % RH and then deliquesced with increasing RH. This is attributed to decreased viscosity and increased ion mobility, which overcome the kinetic inhibition of ion movement, leading to nucleation and growth of Na2SO4 crystal. Our findings highlight the intricate interplay between chemical components within organic/inorganic aerosol, the impact of replacement reactions on aerosol aging and phase state, and subsequently on atmospheric processes.
{"title":"The Impact of Aqueous Phase Replacement Reaction on the Phase State of Internally Mixed Organic/ammonium Aerosols","authors":"Hui Yang, Fengfeng Dong, Li Xia, Qishen Huang, Shufeng Pang, Yunhong Zhang","doi":"10.5194/egusphere-2024-1556","DOIUrl":"https://doi.org/10.5194/egusphere-2024-1556","url":null,"abstract":"<strong>Abstract.</strong> Aerosol phase state is crucial for air quality, climate, and human health. Atmospheric secondary aerosols are often internally mixed with organic and inorganic components, particularly dicarboxylic acids, ammonium, sulfate, nitrate, and chloride. These complex compositions enable aqueous reaction between organic and inorganic species, significantly complicating aerosol phase behaviour during aging and making phase predictions challenging. We investigated carboxylate/ammonium salt mixtures using in-situ infrared spectroscopy. The di- and tri- carboxylates included sodium pyruvate (SP), sodium tartrate (ST), and sodium citrate (SC), while the ammonium salts included NH<sub>4</sub>NO<sub>3</sub>, NH<sub>4</sub>Cl, and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>. Our results demonstrated that aqueous replacement reactions between carboxylates and ammonium salts was promoted by the formation and depletion of NH<sub>3</sub> as relative humidity (RH) changed. Solid NaNO<sub>3</sub>, SP, and Na<sub>2</sub>SO<sub>4</sub> formed in SP/ammonium aerosol at 35.7 %~12.7 %, 64 % and 65.5 %~60.1 % RH, respectively. In contrast, reactions between ST or SC and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> was incomplete due to the gel structure of SC or ST at low RH. Upon hydration, the deliquescence RH of Na<sub>2</sub>SO<sub>4</sub> in SP/(NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> (88.8 %–95.2 %) and NaNO<sub>3</sub> in SP/NH<sub>4</sub>NO<sub>3</sub> (76.5–81.9 %) are higher than those of pure inorganic aerosols. Unexpectedly, aqueous Na<sub>2</sub>SO<sub>4</sub> crystallized upon humidification in ST/(NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> particles at 43.6 % RH and then deliquesced with increasing RH. This is attributed to decreased viscosity and increased ion mobility, which overcome the kinetic inhibition of ion movement, leading to nucleation and growth of Na<sub>2</sub>SO<sub>4</sub> crystal. Our findings highlight the intricate interplay between chemical components within organic/inorganic aerosol, the impact of replacement reactions on aerosol aging and phase state, and subsequently on atmospheric processes.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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