Articles | Volume 23, issue 21
https://doi.org/10.5194/acp-23-13555-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-23-13555-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
30 Oct 2023
Research article |
| 30 Oct 2023
| 30 Oct 2023
Effects of simulated secondary organic aerosol water on PM1 levels and composition over the US
Stylianos Kakavas
Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, Greece
Department of Chemical Engineering, University of Patras, Patras, Greece
Spyros N. Pandis
CORRESPONDING AUTHOR
Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, Greece
Department of Chemical Engineering, University of Patras, Patras, Greece
Athanasios Nenes
CORRESPONDING AUTHOR
Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, Greece
School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Joanna Alden, Nora Bergner, Benjamin Heutte, Lionel Favre, Mihnea Surdu, Julian Weng, Marta Augugliaro, Patrik Winiger, Berkay Dönmez, Roman Pohorsky, Radiance Calmer, Carmelle Chatterjee, Kalliopi Violaki, Athanasios Nenes, Luke Gregor, Silvia Henning, and Julia Schmale
EGUsphere, https://doi.org/10.5194/egusphere-2025-5710, https://doi.org/10.5194/egusphere-2025-5710, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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We investigated the sources, vertical dispersion and properties of aerosols in a Greenlandic fjord system. Four main types were identified: marine background, local anthropogenic, growth events, biomass burning (BB). Anthropogenic emissions increased absorption coefficients, BB significantly increased the CCN number concentrations, growth events were very similar to background with regards to scattering coefficients. Aerosol properties and origins were distinct throughout the boundary layer.
Konstantinos Mataras, Evangelia Siouti, David Patoulias, and Spyros N. Pandis
Atmos. Chem. Phys., 25, 15785–15799, https://doi.org/10.5194/acp-25-15785-2025, https://doi.org/10.5194/acp-25-15785-2025, 2025
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Predicted levels of ultrafine particle mass (PM0.1) vary substantially over Europe with higher values in the summer than in the winter. In summer, PM0.1 was mostly comprised of sulfate (38 %) and secondary organics (32 %). During winter the sulfate fraction increased to 47 % and primary organics contributed 23 %. Correlations between PM0.1 and the regulated PM2.5 were low. This suggests that there are significant differences between the dominant sources and processes of PM0.1 and PM2.5.
Maria P. Georgopoulou, Kalliopi Florou, Angeliki Matrali, Georgia Starida, Christos Kaltsonoudis, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 25, 15835–15855, https://doi.org/10.5194/acp-25-15835-2025, https://doi.org/10.5194/acp-25-15835-2025, 2025
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Residential biomass burning is an important wintertime source of aerosols. This study examined the complex diurnal aging cycles on biomass burning aerosol composition and oxidative potential, a key toxicity metric. Additional organic aerosol (OA) mass was produced after the two (day/night and night/day) cycles, varying from 35 to 90 % of the initial OA. The aging of the emissions led to a final oxidative potential increase of 60 % for both cycles.
Montserrat Costa-Surós, María Gonçalves Ageitos, Marios Chatziparaschos, Paraskevi Georgakaki, Manu Anna Thomas, Gilbert Montané Pinto, Stelios Myriokefalitakis, Twan van Noije, Philippe Le Sager, Maria Kanakidou, Athanasios Nenes, and Carlos Pérez García-Pando
EGUsphere, https://doi.org/10.5194/egusphere-2025-4659, https://doi.org/10.5194/egusphere-2025-4659, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Mixed-phase clouds play a key role in Earth’s climate but remain poorly represented in climate models. We improved their representation in the EC-Earth model by introducing an aerosol-sensitive scheme for ice formation and a machine-learning approach for secondary ice production. These advances produce more realistic cloud properties and radiative effects, highlighting that both processes are essential for reliable climate projections.
Georgia A. Argyropoulou, Kalliopi Florou, and Spyros N. Pandis
Atmos. Meas. Tech., 18, 4969–4983, https://doi.org/10.5194/amt-18-4969-2025, https://doi.org/10.5194/amt-18-4969-2025, 2025
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Ultrafine particles (diameter of less than 100 nm) are suspected to cause significant health effects. Accurately measuring their chemical composition and physical properties in real time is challenging due to their low mass and interference from larger particles. This study proposes a method for the continuous, automated measurement of their composition, tested in a pilot field study to explore their chemical characteristics, physical properties, and sources.
Marios Chatziparaschos, Stelios Myriokefalitakis, Nikos Kalivitis, Nikos Daskalakis, Athanasios Nenes, María Gonçalves Ageitos, Montserrat Costa-Surós, Carlos Pérez García-Pando, Mihalis Vrekoussis, and Maria Kanakidou
Atmos. Chem. Phys., 25, 9085–9111, https://doi.org/10.5194/acp-25-9085-2025, https://doi.org/10.5194/acp-25-9085-2025, 2025
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We show distinct seasonal and geographical patterns in the contributions of mineral dust, marine aerosol, and terrestrial biological particles to ice-nucleating particle (INP) concentrations that lead to atmospheric ice formation, a major source of uncertainty in climate projections. Bioaerosols are the major source of INPs at high temperatures, while mineral dust influences the global INP population at lower temperatures. These particles can satisfactorily reproduce INPs in a climate model.
Anna Maria Neroladaki, Maria Tsagkaraki, Kyriaki Papoutsidaki, Kalliopi Tavernaraki, Filothei Boufidou, Pavlos Zarmpas, Irini Tsiodra, Eleni Liakakou, Aikaterini Bougiatioti, Giorgos Kouvarakis, Nikos Kalivitis, Christos Kaltsonoudis, Athanasios Karagioras, Dimitrios Balis, Konstantinos Mihailidis, Konstantinos Kourtidis, Stelios Myriokefalitakis, Nikos Hatzianastassiou, Spyros N. Pandis, Athanasios Nenes, Nikolaos Mihalopoulos, and Maria Kanakidou
EGUsphere, https://doi.org/10.5194/egusphere-2025-3223, https://doi.org/10.5194/egusphere-2025-3223, 2025
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Aerosol acidity affects aerosol composition and properties, and therefore climate, human health and ecosystems. We use summer and winter fine aerosol observations at 6 sites across Greece, and a thermodynamic model to calculate the spatial and seasonal variability of aerosol acidity. Aerosols were acidic to moderately acidic and more acidic during summer than winter. The importance of organics for aerosol acidity was small. Depending on location different factors controlled aerosol acidity.
Marilena Gidarakou, Alexandros Papayannis, Kunfeng Gao, Panagiotis Gidarakos, Benoit Crouzy, Romanos Foskinis, Sophie Erb, Cuiqi Zhang, Gian Lieberherr, Martine Collaud Coen, Branko Sikoparija, Zamin A. Kanji, Bernard Clot, Bertrand Calpini, Eugenia Giagka, and Athanasios Nenes
EGUsphere, https://doi.org/10.5194/egusphere-2025-2978, https://doi.org/10.5194/egusphere-2025-2978, 2025
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Vertical profiles of pollen and biomass burning particles were obtained at a semi-rural site at the MeteoSwiss station near Payerne (Switzerland) using a novel multi-channel elastic-fluorescence lidar system combined with in situ measurements during the spring 2023 wildfires and pollination season during the PERICLES (PayernE lidaR and Insitu detection of fluorescent bioaerosol and dust partiCLES and their cloud impacts) campaign.
Susanne M. C. Scholz, Vlassis A. Karydis, Georgios I. Gkatzelis, Hendrik Fuchs, Spyros N. Pandis, and Alexandra P. Tsimpidi
EGUsphere, https://doi.org/10.5194/egusphere-2025-2510, https://doi.org/10.5194/egusphere-2025-2510, 2025
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We studied how pollution from cars and trucks contributes to tiny airborne particles that affect air quality and climate. These particles, called secondary organic aerosols, were often underestimated in global models. By improving how certain overlooked emissions from fuel use are represented in our model, we found that their impact is much larger than previously thought. Our results suggest that road traffic plays a far greater role in global air pollution than earlier estimates showed.
Yusuf Bhatti, Duncan Watson-Parris, Leighton Regayre, Hailing Jia, David Neubauer, Ulas Im, Carl Svenhag, Nick Schutgens, Athanasios Tsikerdekis, Athanasios Nenes, Irfan Muhammed, Bastiaan van Diedenhoven, Ardit Arifi, Guangliang Fu, and Otto Hasekamp
EGUsphere, https://doi.org/10.5194/egusphere-2025-2848, https://doi.org/10.5194/egusphere-2025-2848, 2025
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Aerosols (small airborne particles) impact Earth's climate, but their extent is unknown. By running climate model simulations and emulating millions of additional variants with different settings, we found that natural emissions like sea spray and sulfur are key sources of uncertainty in climate predictions. Our work shows that understanding these natural processes better can help improve climate models and make future climate projections more accurate.
David Patoulias, Kalliopi Florou, and Spyros N. Pandis
Geosci. Model Dev., 18, 1103–1118, https://doi.org/10.5194/gmd-18-1103-2025, https://doi.org/10.5194/gmd-18-1103-2025, 2025
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The effect of the assumed atmospheric nucleation mechanism on particle number concentrations and size distribution was investigated. Two quite different mechanisms involving sulfuric acid and ammonia or a biogenic organic vapor gave quite similar results which were consistent with measurements at 26 measurement stations across Europe. The number of larger particles that serve as cloud condensation nuclei showed little sensitivity to the assumed nucleation mechanism.
Alexandros Milousis, Klaus Klingmüller, Alexandra P. Tsimpidi, Jasper F. Kok, Maria Kanakidou, Athanasios Nenes, and Vlassis A. Karydis
Atmos. Chem. Phys., 25, 1333–1351, https://doi.org/10.5194/acp-25-1333-2025, https://doi.org/10.5194/acp-25-1333-2025, 2025
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This study investigates the impact of dust on the global radiative effect of nitrate aerosols. The results indicate both positive and negative regional shortwave and longwave radiative effects due to aerosol–radiation interactions and cloud adjustments. The global average net REari and REaci of nitrate aerosols are −0.11 and +0.17 W m−2, respectively, mainly affecting the shortwave spectrum. Sensitivity simulations evaluated the influence of mineral dust composition and emissions on the results.
Pamela A. Dominutti, Jean-Luc Jaffrezo, Anouk Marsal, Takoua Mhadhbi, Rhabira Elazzouzi, Camille Rak, Fabrizia Cavalli, Jean-Philippe Putaud, Aikaterini Bougiatioti, Nikolaos Mihalopoulos, Despina Paraskevopoulou, Ian Mudway, Athanasios Nenes, Kaspar R. Daellenbach, Catherine Banach, Steven J. Campbell, Hana Cigánková, Daniele Contini, Greg Evans, Maria Georgopoulou, Manuella Ghanem, Drew A. Glencross, Maria Rachele Guascito, Hartmut Herrmann, Saima Iram, Maja Jovanović, Milena Jovašević-Stojanović, Markus Kalberer, Ingeborg M. Kooter, Suzanne E. Paulson, Anil Patel, Esperanza Perdrix, Maria Chiara Pietrogrande, Pavel Mikuška, Jean-Jacques Sauvain, Katerina Seitanidi, Pourya Shahpoury, Eduardo J. d. S. Souza, Sarah Steimer, Svetlana Stevanovic, Guillaume Suarez, P. S. Ganesh Subramanian, Battist Utinger, Marloes F. van Os, Vishal Verma, Xing Wang, Rodney J. Weber, Yuhan Yang, Xavier Querol, Gerard Hoek, Roy M. Harrison, and Gaëlle Uzu
Atmos. Meas. Tech., 18, 177–195, https://doi.org/10.5194/amt-18-177-2025, https://doi.org/10.5194/amt-18-177-2025, 2025
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In this work, 20 labs worldwide collaborated to evaluate the measurement of air pollution's oxidative potential (OP), a key indicator of its harmful effects. The study aimed to identify disparities in the widely used OP dithiothreitol assay and assess the consistency of OP among labs using the same protocol. The results showed that half of the labs achieved acceptable results. However, variability was also found, highlighting the need for standardisation in OP procedures.
Andreas Aktypis, Dontavious J. Sippial, Christina N. Vasilakopoulou, Angeliki Matrali, Christos Kaltsonoudis, Andrea Simonati, Marco Paglione, Matteo Rinaldi, Stefano Decesari, and Spyros N. Pandis
Atmos. Chem. Phys., 24, 13769–13791, https://doi.org/10.5194/acp-24-13769-2024, https://doi.org/10.5194/acp-24-13769-2024, 2024
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A dual-chamber system was deployed in two different environments (Po Valley, Italy, and Pertouli forest, Greece) to study the potential of ambient air directly injected into the chambers, to form secondary organic aerosol (SOA). In the Po Valley, the system reacts rapidly, forming large amounts of SOA, while in Pertouli the SOA formation chemistry appears to have been practically terminated before the beginning of most experiments, so there is little additional SOA formation potential left.
Jiemei Liu, Jesper H. Christensen, Zhuyun Ye, Shikui Dong, Camilla Geels, Jørgen Brandt, Athanasios Nenes, Yuan Yuan, and Ulas Im
Atmos. Chem. Phys., 24, 10849–10867, https://doi.org/10.5194/acp-24-10849-2024, https://doi.org/10.5194/acp-24-10849-2024, 2024
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China was chosen as an example to conduct a quantitative analysis using the Danish Eulerian Hemispheric Model (DEHM) system with meteorological input from the Weather Research and Forecasting (WRF) model. Meteorological conditions and emission inventories contributed 46 % (65 %) and 54 % (35 %) to the variations in PM2.5 concentrations (oxidative potential – OP), respectively, highlighting secondary aerosol formation and biomass burning as the primary contributors to PM2.5 and OP levels.
Manu Anna Thomas, Klaus Wyser, Shiyu Wang, Marios Chatziparaschos, Paraskevi Georgakaki, Montserrat Costa-Surós, Maria Gonçalves Ageitos, Maria Kanakidou, Carlos Pérez García-Pando, Athanasios Nenes, Twan van Noije, Philippe Le Sager, and Abhay Devasthale
Geosci. Model Dev., 17, 6903–6927, https://doi.org/10.5194/gmd-17-6903-2024, https://doi.org/10.5194/gmd-17-6903-2024, 2024
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Aerosol–cloud interactions occur at a range of spatio-temporal scales. While evaluating recent developments in EC-Earth3-AerChem, this study aims to understand the extent to which the Twomey effect manifests itself at larger scales. We find a reduction in the warm bias over the Southern Ocean due to model improvements. While we see footprints of the Twomey effect at larger scales, the negative relationship between cloud droplet number and liquid water drives the shortwave radiative effect.
Kunfeng Gao, Franziska Vogel, Romanos Foskinis, Stergios Vratolis, Maria I. Gini, Konstantinos Granakis, Anne-Claire Billault-Roux, Paraskevi Georgakaki, Olga Zografou, Prodromos Fetfatzis, Alexis Berne, Alexandros Papayannis, Konstantinos Eleftheridadis, Ottmar Möhler, and Athanasios Nenes
Atmos. Chem. Phys., 24, 9939–9974, https://doi.org/10.5194/acp-24-9939-2024, https://doi.org/10.5194/acp-24-9939-2024, 2024
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Ice nucleating particle (INP) concentrations are required for correct predictions of clouds and precipitation in a changing climate, but they are poorly constrained in climate models. We unravel source contributions to INPs in the eastern Mediterranean and find that biological particles are important, regardless of their origin. The parameterizations developed exhibit superior performance and enable models to consider biological-particle effects on INPs.
Romanos Foskinis, Ghislain Motos, Maria I. Gini, Olga Zografou, Kunfeng Gao, Stergios Vratolis, Konstantinos Granakis, Ville Vakkari, Kalliopi Violaki, Andreas Aktypis, Christos Kaltsonoudis, Zongbo Shi, Mika Komppula, Spyros N. Pandis, Konstantinos Eleftheriadis, Alexandros Papayannis, and Athanasios Nenes
Atmos. Chem. Phys., 24, 9827–9842, https://doi.org/10.5194/acp-24-9827-2024, https://doi.org/10.5194/acp-24-9827-2024, 2024
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Analysis of modeling, in situ, and remote sensing measurements reveals the microphysical state of orographic clouds and their response to aerosol from the boundary layer and free troposphere. We show that cloud response to aerosol is robust, as predicted supersaturation and cloud droplet number levels agree with those determined from in-cloud measurements. The ability to determine if clouds are velocity- or aerosol-limited allows for novel model constraints and remote sensing products.
Olga Zografou, Maria Gini, Prodromos Fetfatzis, Konstantinos Granakis, Romanos Foskinis, Manousos Ioannis Manousakas, Fotios Tsopelas, Evangelia Diapouli, Eleni Dovrou, Christina N. Vasilakopoulou, Alexandros Papayannis, Spyros N. Pandis, Athanasios Nenes, and Konstantinos Eleftheriadis
Atmos. Chem. Phys., 24, 8911–8926, https://doi.org/10.5194/acp-24-8911-2024, https://doi.org/10.5194/acp-24-8911-2024, 2024
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Characterization of PM1 and positive matrix factorization (PMF) source apportionment of organic and inorganic fractions were conducted at the high-altitude station (HAC)2. Cloud presence reduced PM1, affecting sulfate more than organics. Free-troposphere (FT) conditions showed more black carbon (eBC) than planetary boundary layer (PBL) conditions.
Olga Zografou, Christos Kaltsonoudis, Maria Gini, Angeliki Matrali, Elias Panagiotopoulos, Alexandros Lekkas, Dimitris Papanastasiou, Spyros N. Pandis, and Konstantinos Eleftheriadis
EGUsphere, https://doi.org/10.5194/egusphere-2024-2126, https://doi.org/10.5194/egusphere-2024-2126, 2024
Preprint archived
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A novel charge transfer ionization orthogonal Time-of-Flight Mass Spectrometer (oToF-MS) was field evaluated for the first time during a field campaign at the suburban DEM station in Athens, Greece from May to August 2023 focusing on key ambient Volatile Organic Compounds (VOCs). The results demonstrate the strengths of the new instrument in performing online, real time measurements of ambient VOCs.
Alexandros Milousis, Alexandra P. Tsimpidi, Holger Tost, Spyros N. Pandis, Athanasios Nenes, Astrid Kiendler-Scharr, and Vlassis A. Karydis
Geosci. Model Dev., 17, 1111–1131, https://doi.org/10.5194/gmd-17-1111-2024, https://doi.org/10.5194/gmd-17-1111-2024, 2024
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This study aims to evaluate the newly developed ISORROPIA-lite aerosol thermodynamic module within the EMAC model and explore discrepancies in global atmospheric simulations of aerosol composition and acidity by utilizing different aerosol phase states. Even though local differences were found in regions where the RH ranged from 20 % to 60 %, on a global scale the results are similar. Therefore, ISORROPIA-lite can be a reliable and computationally effective alternative to ISORROPIA II in EMAC.
Stella E. I. Manavi and Spyros N. Pandis
Atmos. Chem. Phys., 24, 891–909, https://doi.org/10.5194/acp-24-891-2024, https://doi.org/10.5194/acp-24-891-2024, 2024
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Organic vapors of intermediate volatility have often been neglected as sources of atmospheric organic aerosol. In this work we use a new approach for their simulation and quantify the contribution of these compounds emitted by transportation sources (gasoline and diesel vehicles) to particulate matter over Europe. The estimated secondary organic aerosol levels are on average 60 % higher than predicted by previous approaches. However, these estimates are probably lower limits.
Andreas Aktypis, Christos Kaltsonoudis, David Patoulias, Panayiotis Kalkavouras, Angeliki Matrali, Christina N. Vasilakopoulou, Evangelia Kostenidou, Kalliopi Florou, Nikos Kalivitis, Aikaterini Bougiatioti, Konstantinos Eleftheriadis, Stergios Vratolis, Maria I. Gini, Athanasios Kouras, Constantini Samara, Mihalis Lazaridis, Sofia-Eirini Chatoutsidou, Nikolaos Mihalopoulos, and Spyros N. Pandis
Atmos. Chem. Phys., 24, 65–84, https://doi.org/10.5194/acp-24-65-2024, https://doi.org/10.5194/acp-24-65-2024, 2024
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Extensive continuous particle number size distribution measurements took place during two summers (2020 and 2021) at 11 sites in Greece for the investigation of the frequency and the spatial extent of new particle formation. The frequency during summer varied from close to zero in southwestern Greece to more than 60 % in the northern, central, and eastern regions. The spatial variability can be explained by the proximity of the sites to coal-fired power plants and agricultural areas.
Ghislain Motos, Gabriel Freitas, Paraskevi Georgakaki, Jörg Wieder, Guangyu Li, Wenche Aas, Chris Lunder, Radovan Krejci, Julie Thérèse Pasquier, Jan Henneberger, Robert Oscar David, Christoph Ritter, Claudia Mohr, Paul Zieger, and Athanasios Nenes
Atmos. Chem. Phys., 23, 13941–13956, https://doi.org/10.5194/acp-23-13941-2023, https://doi.org/10.5194/acp-23-13941-2023, 2023
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Low-altitude clouds play a key role in regulating the climate of the Arctic, a region that suffers from climate change more than any other on the planet. We gathered meteorological and aerosol physical and chemical data over a year and utilized them for a parameterization that help us unravel the factors driving and limiting the efficiency of cloud droplet formation. We then linked this information to the sources of aerosol found during each season and to processes of cloud glaciation.
Calvin Howes, Pablo E. Saide, Hugh Coe, Amie Dobracki, Steffen Freitag, Jim M. Haywood, Steven G. Howell, Siddhant Gupta, Janek Uin, Mary Kacarab, Chongai Kuang, L. Ruby Leung, Athanasios Nenes, Greg M. McFarquhar, James Podolske, Jens Redemann, Arthur J. Sedlacek, Kenneth L. Thornhill, Jenny P. S. Wong, Robert Wood, Huihui Wu, Yang Zhang, Jianhao Zhang, and Paquita Zuidema
Atmos. Chem. Phys., 23, 13911–13940, https://doi.org/10.5194/acp-23-13911-2023, https://doi.org/10.5194/acp-23-13911-2023, 2023
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To better understand smoke properties and its interactions with clouds, we compare the WRF-CAM5 model with observations from ORACLES, CLARIFY, and LASIC field campaigns in the southeastern Atlantic in August 2017. The model transports and mixes smoke well but does not fully capture some important processes. These include smoke chemical and physical aging over 4–12 days, smoke removal by rain, sulfate particle formation, aerosol activation into cloud droplets, and boundary layer turbulence.
Guangyu Li, Elise K. Wilbourn, Zezhen Cheng, Jörg Wieder, Allison Fagerson, Jan Henneberger, Ghislain Motos, Rita Traversi, Sarah D. Brooks, Mauro Mazzola, Swarup China, Athanasios Nenes, Ulrike Lohmann, Naruki Hiranuma, and Zamin A. Kanji
Atmos. Chem. Phys., 23, 10489–10516, https://doi.org/10.5194/acp-23-10489-2023, https://doi.org/10.5194/acp-23-10489-2023, 2023
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In this work, we present results from an Arctic field campaign (NASCENT) in Ny-Ålesund, Svalbard, on the abundance, variability, physicochemical properties, and potential sources of ice-nucleating particles (INPs) relevant for mixed-phase cloud formation. This work improves the data coverage of Arctic INPs and aerosol properties, allowing for the validation of models predicting cloud microphysical and radiative properties of mixed-phase clouds in the rapidly warming Arctic.
Anne-Claire Billault-Roux, Paraskevi Georgakaki, Josué Gehring, Louis Jaffeux, Alfons Schwarzenboeck, Pierre Coutris, Athanasios Nenes, and Alexis Berne
Atmos. Chem. Phys., 23, 10207–10234, https://doi.org/10.5194/acp-23-10207-2023, https://doi.org/10.5194/acp-23-10207-2023, 2023
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Secondary ice production plays a key role in clouds and precipitation. In this study, we analyze radar measurements from a snowfall event in the Jura Mountains. Complex signatures are observed, which reveal that ice crystals were formed through various processes. An analysis of multi-sensor data suggests that distinct ice multiplication processes were taking place. Both the methods used and the insights gained through this case study contribute to a better understanding of snowfall microphysics.
Mária Lbadaoui-Darvas, Ari Laaksonen, and Athanasios Nenes
Atmos. Chem. Phys., 23, 10057–10074, https://doi.org/10.5194/acp-23-10057-2023, https://doi.org/10.5194/acp-23-10057-2023, 2023
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Heterogeneous ice nucleation is the main ice formation mechanism in clouds. The mechanism of different freezing modes is to date unknown, which results in large model biases. Experiments do not allow for direct observation of ice nucleation at its native resolution. This work uses first principles molecular simulations to determine the mechanism of the least-understood ice nucleation mode and link it to adsorption through a novel modeling framework that unites ice and droplet formation.
Amir Yazdani, Satoshi Takahama, John K. Kodros, Marco Paglione, Mauro Masiol, Stefania Squizzato, Kalliopi Florou, Christos Kaltsonoudis, Spiro D. Jorga, Spyros N. Pandis, and Athanasios Nenes
Atmos. Chem. Phys., 23, 7461–7477, https://doi.org/10.5194/acp-23-7461-2023, https://doi.org/10.5194/acp-23-7461-2023, 2023
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Organic aerosols directly emitted from wood and pellet stove combustion are found to chemically transform (approximately 15 %–35 % by mass) under daytime aging conditions simulated in an environmental chamber. A new marker for lignin-like compounds is found to degrade at a different rate than previously identified biomass burning markers and can potentially provide indication of aging time in ambient samples.
Petro Uruci, Dontavious Sippial, Anthoula Drosatou, and Spyros N. Pandis
Atmos. Meas. Tech., 16, 3155–3172, https://doi.org/10.5194/amt-16-3155-2023, https://doi.org/10.5194/amt-16-3155-2023, 2023
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In this work we develop an algorithm for the synthesis of the measurements performed in atmospheric simulation chambers regarding the formation of secondary organic aerosol (SOA). Novel features of the algorithm are its ability to use measurements of SOA yields, thermodenuders, and isothermal dilution; its estimation of parameters that can be used directly in atmospheric chemical transport models; and finally its estimates of the uncertainty in SOA formation yields.
Christina N. Vasilakopoulou, Kalliopi Florou, Christos Kaltsonoudis, Iasonas Stavroulas, Nikolaos Mihalopoulos, and Spyros N. Pandis
Atmos. Meas. Tech., 16, 2837–2850, https://doi.org/10.5194/amt-16-2837-2023, https://doi.org/10.5194/amt-16-2837-2023, 2023
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The offline aerosol mass spectrometry technique is a useful tool for the source apportionment of organic aerosol in areas and periods during which an aerosol mass spectrometer is not available. In this work, an improved offline technique was developed and evaluated in an effort to capture most of the partially soluble and insoluble organic aerosol material, reducing the uncertainty of the corresponding source apportionment significantly.
Emily D. Lenhardt, Lan Gao, Jens Redemann, Feng Xu, Sharon P. Burton, Brian Cairns, Ian Chang, Richard A. Ferrare, Chris A. Hostetler, Pablo E. Saide, Calvin Howes, Yohei Shinozuka, Snorre Stamnes, Mary Kacarab, Amie Dobracki, Jenny Wong, Steffen Freitag, and Athanasios Nenes
Atmos. Meas. Tech., 16, 2037–2054, https://doi.org/10.5194/amt-16-2037-2023, https://doi.org/10.5194/amt-16-2037-2023, 2023
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Small atmospheric particles, such as smoke from wildfires or pollutants from human activities, impact cloud properties, and clouds have a strong influence on climate. To better understand the distributions of these particles, we develop relationships to derive their concentrations from remote sensing measurements from an instrument called a lidar. Our method is reliable for smoke particles, and similar steps can be taken to develop relationships for other particle types.
Marios Chatziparaschos, Nikos Daskalakis, Stelios Myriokefalitakis, Nikos Kalivitis, Athanasios Nenes, María Gonçalves Ageitos, Montserrat Costa-Surós, Carlos Pérez García-Pando, Medea Zanoli, Mihalis Vrekoussis, and Maria Kanakidou
Atmos. Chem. Phys., 23, 1785–1801, https://doi.org/10.5194/acp-23-1785-2023, https://doi.org/10.5194/acp-23-1785-2023, 2023
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Ice formation is enabled by ice-nucleating particles (INP) at higher temperatures than homogeneous formation and can profoundly affect the properties of clouds. Our global model results show that K-feldspar is the most important contributor to INP concentrations globally, affecting mid-level mixed-phase clouds. However, quartz can significantly contribute and dominates the lowest and the highest altitudes of dust-derived INP, affecting mainly low-level and high-level mixed-phase clouds.
Spiro D. Jorga, Kalliopi Florou, David Patoulias, and Spyros N. Pandis
Atmos. Chem. Phys., 23, 85–97, https://doi.org/10.5194/acp-23-85-2023, https://doi.org/10.5194/acp-23-85-2023, 2023
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We take advantage of this unexpected low, new particle formation frequency in Greece and use a dual atmospheric simulation chamber system with starting point ambient air in an effort to gain insight about the chemical species that is limiting nucleation in this area. A potential nucleation precursor, ammonia, was added in one of the chambers while the other one was used as a reference. The addition of ammonia assisted new particle formation in almost 50 % of the experiments conducted.
Brian T. Dinkelacker, Pablo Garcia Rivera, Ioannis Kioutsioukis, Peter J. Adams, and Spyros N. Pandis
Geosci. Model Dev., 15, 8899–8912, https://doi.org/10.5194/gmd-15-8899-2022, https://doi.org/10.5194/gmd-15-8899-2022, 2022
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The performance of a chemical transport model in reproducing PM2.5 concentrations and composition was evaluated at the finest scale using measurements from regulatory sites as well as a network of low-cost monitors. Total PM2.5 mass is reproduced well by the model during the winter when compared to regulatory measurements, but in the summer PM2.5 is underpredicted, mainly due to difficulties in reproducing regional secondary organic aerosol levels.
Christina Vasilakopoulou, Iasonas Stavroulas, Nikolaos Mihalopoulos, and Spyros N. Pandis
Atmos. Meas. Tech., 15, 6419–6431, https://doi.org/10.5194/amt-15-6419-2022, https://doi.org/10.5194/amt-15-6419-2022, 2022
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Offline aerosol mass spectrometer (AMS) measurements can provide valuable information about ambient organic aerosols when online AMS measurements are not available. In this study, we examine whether and how the low time resolution (usually 24 h) of the offline technique affects source apportionment results. We concluded that use of the daily averages resulted in estimated average contributions that were within 8 % of the total OA compared with the high-resolution analysis.
Stella E. I. Manavi and Spyros N. Pandis
Geosci. Model Dev., 15, 7731–7749, https://doi.org/10.5194/gmd-15-7731-2022, https://doi.org/10.5194/gmd-15-7731-2022, 2022
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The paper describes the first step towards the development of a simulation framework for the chemistry and secondary organic aerosol production of intermediate-volatility organic compounds (IVOCs). These compounds can be a significant source of organic particulate matter. Our approach treats IVOCs as lumped compounds that retain their chemical characteristics. Estimated IVOC emissions from road transport were a factor of 8 higher than emissions used in previous applications.
Aristeidis Voliotis, Mao Du, Yu Wang, Yunqi Shao, Thomas J. Bannan, Michael Flynn, Spyros N. Pandis, Carl J. Percival, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 22, 13677–13693, https://doi.org/10.5194/acp-22-13677-2022, https://doi.org/10.5194/acp-22-13677-2022, 2022
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The addition of a low-yield precursor to the reactive mixture of aVOC and bVOC can increase or decrease the SOA volatility that is system-dependent. Therefore, the SOA volatility of the mixtures cannot always be predicted based on the additivity. In complex mixtures the formation of lower-volatility products likely outweighs the formation of products with higher volatility. The unique products of each mixture contribute significantly to the signal, suggesting interactions can be important.
Brian T. Dinkelacker, Pablo Garcia Rivera, Ksakousti Skyllakou, Peter J. Adams, and Spyros N. Pandis
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-648, https://doi.org/10.5194/acp-2022-648, 2022
Revised manuscript not accepted
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A number of factors have influenced the biogenic secondary organic aerosol (SOA) levels in the southeastern US from 2001 to 2010. The increases in temperature have led to an increase of the emissions of biogenic volatile organic compounds by trees and a corresponding increase of the SOA. However, this increase has been balanced by the reductions in the anthropogenic emissions of organic gases and particulate matter as well as of the oxides of nitrogen keeping the biogenic SOA roughly constant.
Caroline Dang, Michal Segal-Rozenhaimer, Haochi Che, Lu Zhang, Paola Formenti, Jonathan Taylor, Amie Dobracki, Sara Purdue, Pui-Shan Wong, Athanasios Nenes, Arthur Sedlacek III, Hugh Coe, Jens Redemann, Paquita Zuidema, Steven Howell, and James Haywood
Atmos. Chem. Phys., 22, 9389–9412, https://doi.org/10.5194/acp-22-9389-2022, https://doi.org/10.5194/acp-22-9389-2022, 2022
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Transmission electron microscopy was used to analyze aged African smoke particles and how the smoke interacts with the marine atmosphere. We found that the volatility of organic aerosol increases with biomass burning plume age, that black carbon is often mixed with potassium salts and that the marine atmosphere can incorporate Na and Cl into smoke particles. Marine salts are more processed when mixed with smoke plumes, and there are interesting Cl-rich yet Na-absent marine particles.
Lu Zhang, Michal Segal-Rozenhaimer, Haochi Che, Caroline Dang, Arthur J. Sedlacek III, Ernie R. Lewis, Amie Dobracki, Jenny P. S. Wong, Paola Formenti, Steven G. Howell, and Athanasios Nenes
Atmos. Chem. Phys., 22, 9199–9213, https://doi.org/10.5194/acp-22-9199-2022, https://doi.org/10.5194/acp-22-9199-2022, 2022
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Widespread biomass burning (BB) events occur annually in Africa and contribute ~ 1 / 3 of global BB emissions, which contain a large family of light-absorbing organics, known as brown carbon (BrC), whose absorption of incident radiation is difficult to estimate, leading to large uncertainties in the global radiative forcing estimation. This study quantifies the BrC absorption of aged BB particles and highlights the potential presence of absorbing iron oxides in this climatically important region.
Stelios Myriokefalitakis, Elisa Bergas-Massó, María Gonçalves-Ageitos, Carlos Pérez García-Pando, Twan van Noije, Philippe Le Sager, Akinori Ito, Eleni Athanasopoulou, Athanasios Nenes, Maria Kanakidou, Maarten C. Krol, and Evangelos Gerasopoulos
Geosci. Model Dev., 15, 3079–3120, https://doi.org/10.5194/gmd-15-3079-2022, https://doi.org/10.5194/gmd-15-3079-2022, 2022
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We here describe the implementation of atmospheric multiphase processes in the EC-Earth Earth system model. We provide global budgets of oxalate, sulfate, and iron-containing aerosols, along with an analysis of the links among atmospheric composition, aqueous-phase processes, and aerosol dissolution, supported by comparison to observations. This work is a first step towards an interactive calculation of the deposition of bioavailable atmospheric iron coupled to the model’s ocean component.
Pablo Garcia Rivera, Brian T. Dinkelacker, Ioannis Kioutsioukis, Peter J. Adams, and Spyros N. Pandis
Atmos. Chem. Phys., 22, 2011–2027, https://doi.org/10.5194/acp-22-2011-2022, https://doi.org/10.5194/acp-22-2011-2022, 2022
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The contribution of various pollution sources to the variability of fine PM in an urban area was examined using as an example the city of Pittsburgh. Biomass burning aerosol shows the largest variability during the winter with local maxima within the city and in the suburbs. During both periods the largest contributing source to the average PM2.5 is particles from outside the modeling domain. The average population-weighted PM2.5 concentration does not change significantly with resolution.
Paraskevi Georgakaki, Georgia Sotiropoulou, Étienne Vignon, Anne-Claire Billault-Roux, Alexis Berne, and Athanasios Nenes
Atmos. Chem. Phys., 22, 1965–1988, https://doi.org/10.5194/acp-22-1965-2022, https://doi.org/10.5194/acp-22-1965-2022, 2022
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The modelling study focuses on the importance of ice multiplication processes in orographic mixed-phase clouds, which is one of the least understood cloud types in the climate system. We show that the consideration of ice seeding and secondary ice production through ice–ice collisional breakup is essential for correct predictions of precipitation in mountainous terrain, with important implications for radiation processes.
David Patoulias and Spyros N. Pandis
Atmos. Chem. Phys., 22, 1689–1706, https://doi.org/10.5194/acp-22-1689-2022, https://doi.org/10.5194/acp-22-1689-2022, 2022
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Our simulations indicate that the recently identified production and subsequent condensation effect of extremely low-volatility organic compounds have a smaller-than-expected effect on the total concentration of atmospheric particles. On the other hand, the oxidation of intermediate-volatility organic compounds leads to decreases in the ultrafine-particle concentrations. These results improve our understanding of the links between secondary organic aerosol formation and ultrafine particles.
Miska Olin, David Patoulias, Heino Kuuluvainen, Jarkko V. Niemi, Topi Rönkkö, Spyros N. Pandis, Ilona Riipinen, and Miikka Dal Maso
Atmos. Chem. Phys., 22, 1131–1148, https://doi.org/10.5194/acp-22-1131-2022, https://doi.org/10.5194/acp-22-1131-2022, 2022
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An emission factor particle size distribution was determined from the measurements at an urban traffic site. It was used in updating a pre-existing emission inventory, and regional modeling was performed after the update. Emission inventories typically underestimate nanoparticle emissions due to challenges in determining them with high certainty. This update reveals that the simulated aerosol levels have previously been underestimated especially for urban areas and for sub-50 nm particles.
Irini Tsiodra, Georgios Grivas, Kalliopi Tavernaraki, Aikaterini Bougiatioti, Maria Apostolaki, Despina Paraskevopoulou, Alexandra Gogou, Constantine Parinos, Konstantina Oikonomou, Maria Tsagkaraki, Pavlos Zarmpas, Athanasios Nenes, and Nikolaos Mihalopoulos
Atmos. Chem. Phys., 21, 17865–17883, https://doi.org/10.5194/acp-21-17865-2021, https://doi.org/10.5194/acp-21-17865-2021, 2021
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We analyze observations from year-long measurements at Athens, Greece. Nighttime wintertime PAH levels are 4 times higher than daytime, and wintertime values are 15 times higher than summertime. Biomass burning aerosol during wintertime pollution events is responsible for these significant wintertime enhancements and accounts for 43 % of the population exposure to PAH carcinogenic risk. Biomass burning poses additional health risks beyond those associated with the high PM levels that develop.
Mária Lbadaoui-Darvas, Satoshi Takahama, and Athanasios Nenes
Atmos. Chem. Phys., 21, 17687–17714, https://doi.org/10.5194/acp-21-17687-2021, https://doi.org/10.5194/acp-21-17687-2021, 2021
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Aerosol–cloud interactions constitute the most uncertain contribution to climate change. The uptake kinetics of water by aerosol is a central process of cloud droplet formation, yet its molecular-scale mechanism is unknown. We use molecular simulations to study this process for phase-separated organic particles. Our results explain the increased cloud condensation activity of such particles and can be generalized over various compositions, thus possibly serving as a basis for future models.
Ksakousti Skyllakou, Pablo Garcia Rivera, Brian Dinkelacker, Eleni Karnezi, Ioannis Kioutsioukis, Carlos Hernandez, Peter J. Adams, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 17115–17132, https://doi.org/10.5194/acp-21-17115-2021, https://doi.org/10.5194/acp-21-17115-2021, 2021
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Significant reductions in pollutant emissions took place in the US from 1990 to 2010. The reductions in sulfur dioxide emissions from electric-generating units have dominated the reductions in fine particle mass. The reductions in transportation emissions have led to a 30 % reduction of elemental concentrations and of organic particulate matter by a factor of 3. On the other hand, changes in biomass burning and biogenic secondary organic aerosol have been modest.
Spiro D. Jorga, Kalliopi Florou, Christos Kaltsonoudis, John K. Kodros, Christina Vasilakopoulou, Manuela Cirtog, Axel Fouqueau, Bénédicte Picquet-Varrault, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 15337–15349, https://doi.org/10.5194/acp-21-15337-2021, https://doi.org/10.5194/acp-21-15337-2021, 2021
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We test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through the oxidation of the emitted organic vapors by the nitrate radicals produced during the reaction of ozone and nitrogen oxides. Our experiments, using as a starting point the ambient air of an urban area with high biomass burning activity, demonstrate that, even with sunlight, there is 20 %–70 % additional organic aerosol formed in a few hours.
Aristeidis Voliotis, Yu Wang, Yunqi Shao, Mao Du, Thomas J. Bannan, Carl J. Percival, Spyros N. Pandis, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 21, 14251–14273, https://doi.org/10.5194/acp-21-14251-2021, https://doi.org/10.5194/acp-21-14251-2021, 2021
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Secondary organic aerosol (SOA) formation from mixtures of volatile precursors can be affected by the molecular interactions of the products. Composition and volatility measurements of SOA formed from mixtures of anthropogenic and biogenic precursors reveal processes that can increase or decrease the SOA volatility. The unique products of the mixture were more oxygenated and less volatile than those from either precursor. Analytical context is provided to explore the SOA volatility in mixtures.
Andreas Tilgner, Thomas Schaefer, Becky Alexander, Mary Barth, Jeffrey L. Collett Jr., Kathleen M. Fahey, Athanasios Nenes, Havala O. T. Pye, Hartmut Herrmann, and V. Faye McNeill
Atmos. Chem. Phys., 21, 13483–13536, https://doi.org/10.5194/acp-21-13483-2021, https://doi.org/10.5194/acp-21-13483-2021, 2021
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Feedbacks of acidity and atmospheric multiphase chemistry in deliquesced particles and clouds are crucial for the tropospheric composition, depositions, climate, and human health. This review synthesizes the current scientific knowledge on these feedbacks using both inorganic and organic aqueous-phase chemistry. Finally, this review outlines atmospheric implications and highlights the need for future investigations with respect to reducing emissions of key acid precursors in a changing world.
Paraskevi Georgakaki, Aikaterini Bougiatioti, Jörg Wieder, Claudia Mignani, Fabiola Ramelli, Zamin A. Kanji, Jan Henneberger, Maxime Hervo, Alexis Berne, Ulrike Lohmann, and Athanasios Nenes
Atmos. Chem. Phys., 21, 10993–11012, https://doi.org/10.5194/acp-21-10993-2021, https://doi.org/10.5194/acp-21-10993-2021, 2021
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Aerosol and cloud observations coupled with a droplet activation parameterization was used to investigate the aerosol–cloud droplet link in alpine mixed-phase clouds. Predicted droplet number, Nd, agrees with observations and never exceeds a characteristic “limiting droplet number”, Ndlim, which depends solely on σw. Nd becomes velocity limited when it is within 50 % of Ndlim. Identifying when dynamical changes control Nd variability is central for understanding aerosol–cloud interactions.
Georgia Sotiropoulou, Luisa Ickes, Athanasios Nenes, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 9741–9760, https://doi.org/10.5194/acp-21-9741-2021, https://doi.org/10.5194/acp-21-9741-2021, 2021
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Mixed-phase clouds are a large source of uncertainty in projections of the Arctic climate. This is partly due to the poor representation of the cloud ice formation processes. Implementing a parameterization for ice multiplication due to mechanical breakup upon collision of two ice particles in a high-resolution model improves cloud ice phase representation; however, cloud liquid remains overestimated.
Athanasios Nenes, Spyros N. Pandis, Maria Kanakidou, Armistead G. Russell, Shaojie Song, Petros Vasilakos, and Rodney J. Weber
Atmos. Chem. Phys., 21, 6023–6033, https://doi.org/10.5194/acp-21-6023-2021, https://doi.org/10.5194/acp-21-6023-2021, 2021
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Ecosystems and air quality are affected by the dry deposition of inorganic reactive nitrogen (Nr, the sum of ammonium and nitrate). Its large variability is driven by the large difference in deposition velocity of N when in the gas or particle phase. Here we show that aerosol liquid water and acidity, by affecting gas–particle partitioning, modulate the dry deposition velocity of NH3, HNO3, and Nr worldwide. These effects explain the rapid accumulation of nitrate aerosol during haze events.
Georgia N. Theodoritsi, Giancarlo Ciarelli, and Spyros N. Pandis
Geosci. Model Dev., 14, 2041–2055, https://doi.org/10.5194/gmd-14-2041-2021, https://doi.org/10.5194/gmd-14-2041-2021, 2021
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Two schemes based on the volatility basis set were used for the simulation of biomass burning organic aerosol (bbOA) in the continental US. The first is the default scheme of the PMCAMx-SR model, and the second is a recently developed scheme based on laboratory experiments. The alternative bbOA scheme predicts much higher concentrations. The default scheme performed better during summer and fall, while the alternative scheme was a little better during spring.
Weiqi Xu, Chun Chen, Yanmei Qiu, Ying Li, Zhiqiang Zhang, Eleni Karnezi, Spyros N. Pandis, Conghui Xie, Zhijie Li, Jiaxing Sun, Nan Ma, Wanyun Xu, Pingqing Fu, Zifa Wang, Jiang Zhu, Douglas R. Worsnop, Nga Lee Ng, and Yele Sun
Atmos. Chem. Phys., 21, 5463–5476, https://doi.org/10.5194/acp-21-5463-2021, https://doi.org/10.5194/acp-21-5463-2021, 2021
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Here aerosol volatility and viscosity at a rural site (Gucheng) and an urban site (Beijing) in the North China Plain (NCP) were investigated in summer and winter. Our results showed that organic aerosol (OA) in winter in the NCP is more volatile than that in summer due to enhanced primary emissions from coal combustion and biomass burning. We also found that OA existed mainly as a solid in winter in Beijing but as semisolids in Beijing in summer and Gucheng in winter.
Yilin Chen, Huizhong Shen, Jennifer Kaiser, Yongtao Hu, Shannon L. Capps, Shunliu Zhao, Amir Hakami, Jhih-Shyang Shih, Gertrude K. Pavur, Matthew D. Turner, Daven K. Henze, Jaroslav Resler, Athanasios Nenes, Sergey L. Napelenok, Jesse O. Bash, Kathleen M. Fahey, Gregory R. Carmichael, Tianfeng Chai, Lieven Clarisse, Pierre-François Coheur, Martin Van Damme, and Armistead G. Russell
Atmos. Chem. Phys., 21, 2067–2082, https://doi.org/10.5194/acp-21-2067-2021, https://doi.org/10.5194/acp-21-2067-2021, 2021
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Ammonia (NH3) emissions can exert adverse impacts on air quality and ecosystem well-being. NH3 emission inventories are viewed as highly uncertain. Here we optimize the NH3 emission estimates in the US using an air quality model and NH3 measurements from the IASI satellite instruments. The optimized NH3 emissions are much higher than the National Emissions Inventory estimates in April. The optimized NH3 emissions improved model performance when evaluated against independent observation.
Jens Redemann, Robert Wood, Paquita Zuidema, Sarah J. Doherty, Bernadette Luna, Samuel E. LeBlanc, Michael S. Diamond, Yohei Shinozuka, Ian Y. Chang, Rei Ueyama, Leonhard Pfister, Ju-Mee Ryoo, Amie N. Dobracki, Arlindo M. da Silva, Karla M. Longo, Meloë S. Kacenelenbogen, Connor J. Flynn, Kristina Pistone, Nichola M. Knox, Stuart J. Piketh, James M. Haywood, Paola Formenti, Marc Mallet, Philip Stier, Andrew S. Ackerman, Susanne E. Bauer, Ann M. Fridlind, Gregory R. Carmichael, Pablo E. Saide, Gonzalo A. Ferrada, Steven G. Howell, Steffen Freitag, Brian Cairns, Brent N. Holben, Kirk D. Knobelspiesse, Simone Tanelli, Tristan S. L'Ecuyer, Andrew M. Dzambo, Ousmane O. Sy, Greg M. McFarquhar, Michael R. Poellot, Siddhant Gupta, Joseph R. O'Brien, Athanasios Nenes, Mary Kacarab, Jenny P. S. Wong, Jennifer D. Small-Griswold, Kenneth L. Thornhill, David Noone, James R. Podolske, K. Sebastian Schmidt, Peter Pilewskie, Hong Chen, Sabrina P. Cochrane, Arthur J. Sedlacek, Timothy J. Lang, Eric Stith, Michal Segal-Rozenhaimer, Richard A. Ferrare, Sharon P. Burton, Chris A. Hostetler, David J. Diner, Felix C. Seidel, Steven E. Platnick, Jeffrey S. Myers, Kerry G. Meyer, Douglas A. Spangenberg, Hal Maring, and Lan Gao
Atmos. Chem. Phys., 21, 1507–1563, https://doi.org/10.5194/acp-21-1507-2021, https://doi.org/10.5194/acp-21-1507-2021, 2021
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Southern Africa produces significant biomass burning emissions whose impacts on regional and global climate are poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA investigation designed to study the key processes that determine these climate impacts. The main purpose of this paper is to familiarize the broader scientific community with the ORACLES project, the dataset it produced, and the most important initial findings.
Stylianos Kakavas, David Patoulias, Maria Zakoura, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 799–811, https://doi.org/10.5194/acp-21-799-2021, https://doi.org/10.5194/acp-21-799-2021, 2021
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The dependence of aerosol acidity on particle size, location, and altitude over Europe during a summertime period is investigated. Differences of up to 1–4 pH units are predicted between sub- and supermicron particles in northern and southern Europe. Particles of all sizes become increasingly acidic with altitude (0.5–2.5 pH units decrease over 2.5 km). The size-dependent pH differences carry important implications for pH-sensitive processes in the aerosol.
Georgia Sotiropoulou, Étienne Vignon, Gillian Young, Hugh Morrison, Sebastian J. O'Shea, Thomas Lachlan-Cope, Alexis Berne, and Athanasios Nenes
Atmos. Chem. Phys., 21, 755–771, https://doi.org/10.5194/acp-21-755-2021, https://doi.org/10.5194/acp-21-755-2021, 2021
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Summer clouds have a significant impact on the radiation budget of the Antarctic surface and thus on ice-shelf melting. However, these are poorly represented in climate models due to errors in their microphysical structure, including the number of ice crystals that they contain. We show that breakup from ice particle collisions can substantially magnify the ice crystal number concentration with significant implications for surface radiation. This process is currently missing in climate models.
Johannes Quaas, Antti Arola, Brian Cairns, Matthew Christensen, Hartwig Deneke, Annica M. L. Ekman, Graham Feingold, Ann Fridlind, Edward Gryspeerdt, Otto Hasekamp, Zhanqing Li, Antti Lipponen, Po-Lun Ma, Johannes Mülmenstädt, Athanasios Nenes, Joyce E. Penner, Daniel Rosenfeld, Roland Schrödner, Kenneth Sinclair, Odran Sourdeval, Philip Stier, Matthias Tesche, Bastiaan van Diedenhoven, and Manfred Wendisch
Atmos. Chem. Phys., 20, 15079–15099, https://doi.org/10.5194/acp-20-15079-2020, https://doi.org/10.5194/acp-20-15079-2020, 2020
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Anthropogenic pollution particles – aerosols – serve as cloud condensation nuclei and thus increase cloud droplet concentration and the clouds' reflection of sunlight (a cooling effect on climate). This Twomey effect is poorly constrained by models and requires satellite data for better quantification. The review summarizes the challenges in properly doing so and outlines avenues for progress towards a better use of aerosol retrievals and better retrievals of droplet concentrations.
Cited articles
Baker, A., Kanakidou, M., Nenes, A., Myriokefalitakis, S., Croot, P.L., Duce, A. D., Gao, Y., Guieu, C., Ito, A., Jickells, T. D., Mahowald, N. M., Middag, R., Perron, M. M. G., Sarin, M. M., Shelley, R., and Turner, D. R.: Changing atmospheric acidity as a modulator of nutrient deposition and ocean biogeochemistry, Sci. Adv., 7, 1–9, https://doi.org/10.1126/sciadv.abd8800, 2021.
Bian, Y. X., Zhao, C. S., Ma, N., Chen, J., and Xu, W. Y.: A study of aerosol liquid water content based on hygroscopicity measurements at high relative humidity in the North China Plain, Atmos. Chem. Phys., 14, 6417–6426, https://doi.org/10.5194/acp-14-6417-2014, 2014.
Bougiatioti, A., Nikolaou, P., Stavroulas, I., Kouvarakis, G., Weber, R., Nenes, A., Kanakidou, M., and Mihalopoulos, N.: Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability, Atmos. Chem. Phys., 16, 4579–4591, https://doi.org/10.5194/acp-16-4579-2016, 2016.
Carlton, A. G. and Turpin, B. J.: Particle partitioning potential of organic compounds is highest in the Eastern US and driven by anthropogenic water, Atmos. Chem. Phys., 13, 10203–10214, https://doi.org/10.5194/acp-13-10203-2013, 2013.
Chang, R. Y.-W., Slowik, J. G., Shantz, N. C., Vlasenko, A., Liggio, J., Sjostedt, S. J., Leaitch, W. R., and Abbatt, J. P. D.: The hygroscopicity parameter (κ) of ambient organic aerosol at a field site subject to biogenic and anthropogenic influences: relationship to degree of aerosol oxidation, Atmos. Chem. Phys., 10, 5047–5064, https://doi.org/10.5194/acp-10-5047-2010, 2010.
Deetz, K., Vogel, H., Haslett, S., Knippertz, P., Coe, H., and Vogel, B.: Aerosol liquid water content in the moist southern West African monsoon layer and its radiative impact, Atmos. Chem. Phys., 18, 14271–14295, https://doi.org/10.5194/acp-18-14271-2018, 2018.
Donahue, N. M., Robinson, A. L., Stanier, C. O., and Pandis, S. N.: Coupled partitioning, dilution, and chemical aging of semivolatile organics, Environ. Sci. Technol., 40, 2635–2643, 2006.
Environ: Comprehensive Air Quality Model with Extensions Version 4.40, Users Guide, ENVIRON Int. Corp., Novato, CA, http://www.camx.com (last access: November 2020), 2006.
Fahey, K. and Pandis, S. N.: Optimizing model performance: variable size resolution in cloud chemistry modeling, Atmos. Environ., 35, 4471–4478, 2001.
Fountoukis, C. and Nenes, A.: ISORROPIA II: a computationally efficient thermodynamic equilibrium model for K+–Ca2+–Mg2+–NH4+–Na+–SO
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Short summary
Water uptake from organic species in aerosol can affect the partitioning of semi-volatile inorganic compounds but are not considered in global and chemical transport models. We address this with a version of the PM-CAMx model that considers such organic water effects and use it to carry out 1-year aerosol simulations over the continental US. We show that such organic water impacts can increase dry PM1 levels by up to 2 μg m-3 when RH levels and PM1 concentrations are high.
Water uptake from organic species in aerosol can affect the partitioning of semi-volatile...
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