Articles | Volume 22, issue 3
https://doi.org/10.5194/acp-22-2011-2022
© Author(s) 2022. 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-22-2011-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Feb 2022
Research article |
| 11 Feb 2022
| 11 Feb 2022
Source-resolved variability of fine particulate matter and human exposure in an urban area
Pablo Garcia Rivera
Department of Chemical Engineering, Carnegie Mellon University,
Pittsburgh, PA, 15213, USA
Brian T. Dinkelacker
Department of Chemical Engineering, Carnegie Mellon University,
Pittsburgh, PA, 15213, USA
Ioannis Kioutsioukis
Department of Physics, University of Patras, 26500, Patras, Greece
Peter J. Adams
Department of Civil and Environmental Engineering, Carnegie Mellon
University, Pittsburgh, PA, 15213, USA
Department of Engineering and Public Policy, Carnegie Mellon
University, Pittsburgh, PA, 15213, USA
Spyros N. Pandis
CORRESPONDING AUTHOR
Institute of Chemical Engineering Sciences (FORTH/ICE-HT), 26504,
Patras, Greece
Department of Chemical Engineering, University of Patras, 26500,
Patras, Greece
Related authors
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Georgia A. Argyropoulou, Kalliopi Florou, and Spyros N. Pandis
EGUsphere, https://doi.org/10.5194/egusphere-2025-1147, https://doi.org/10.5194/egusphere-2025-1147, 2025
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
Ultrafine particles (diameter 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.
Ioannis Kioutsioukis, Christian Hogrefe, Paul A. Makar, Ummugulsun Alyuz, Jessy O. Bash, Roberto Bellasio, Roberto Bianconi, Tim Buttler, Olivia E. Clifton, Philippe Cheung, Alma Hodzic, Richard Kranenburg, Aurelia Lupascu, Kester Momoh, Juan Luis Perez-Camaño, John Pleim, Young-Hee Ryu, Robero San Jose, Donna Schwede, Ranjeet Sokhi, and Stefano Galmarini
EGUsphere, https://doi.org/10.5194/egusphere-2025-1091, https://doi.org/10.5194/egusphere-2025-1091, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Deposition is a key in air quality modelling. An evaluation of the AQMEII4 models is performed prior to analysing the different deposition schemes in relation to the LULC used. Such analysis is unprecedented. Among the results, LULC masks have to be harmonised and up-to-date information used in place of outdated and too course masks. Alternatively LULC masks should be evaluated and intercom pared when multiple model results are analysed.
Paul A. Makar, Philip Cheung, Christian Hogrefe, Ayodeji Akingunola, Ummugulsum Alyuz, Jesse O. Bash, Michael D. Bell, Roberto Bellasio, Roberto Bianconi, Tim Butler, Hazel Cathcart, Olivia E. Clifton, Alma Hodzic, Ioannis Kioutsioukis, Richard Kranenburg, Aurelia Lupascu, Jason A. Lynch, Kester Momoh, Juan L. Perez-Camanyo, Jonathan Pleim, Young-Hee Ryu, Roberto San Jose, Donna Schwede, Thomas Scheuschner, Mark W. Shephard, Ranjeet S. Sokhi, and Stefano Galmarini
Atmos. Chem. Phys., 25, 3049–3107, https://doi.org/10.5194/acp-25-3049-2025, https://doi.org/10.5194/acp-25-3049-2025, 2025
Short summary
Short summary
The large range of sulfur and nitrogen deposition estimates from air quality models results in a large range of predicted impacts. We used models and deposition diagnostics to identify the processes controlling atmospheric sulfur and nitrogen deposition variability. Controlling factors included the uptake of gases and aerosols by hydrometeors, aerosol inorganic chemistry, particle dry deposition, ammonia bidirectional fluxes, gas deposition via plant cuticles and soil, and land use data.
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
Short summary
Short summary
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.
Christian Hogrefe, Stefano Galmarini, Paul A. Makar, Ioannis Kioutsioukis, Olivia E. Clifton, Ummugulsum Alyuz, Jesse O. Bash, Roberto Bellasio, Roberto Bianconi, Tim Butler, Philip Cheung, Alma Hodzic, Richard Kranenburg, Aurelia Lupascu, Kester Momoh, Juan Luis Perez-Camanyo, Jonathan E. Pleim, Young-Hee Ryu, Roberto San Jose, Martijn Schaap, Donna B. Schwede, and Ranjeet Sokhi
EGUsphere, https://doi.org/10.5194/egusphere-2025-225, https://doi.org/10.5194/egusphere-2025-225, 2025
Short summary
Short summary
Performed under the umbrella of the fourth phase of the Air Quality Model Evaluation International Initiative (AQMEII4), this study applies AQMEII4 diagnostic tools to better characterize how dry deposition removes pollutants from the atmosphere in regional-scale models. The results also strongly suggest that improvement and harmonization of the representation of land use in these models would serve the community in their future development efforts.
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
Short summary
Short summary
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.
Konstantinos Mataras, Evangelia Siouti, David Patoulias, and Spyros Pandis
EGUsphere, https://doi.org/10.5194/egusphere-2024-3357, https://doi.org/10.5194/egusphere-2024-3357, 2024
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Stylianos Kakavas, Spyros N. Pandis, and Athanasios Nenes
Atmos. Chem. Phys., 23, 13555–13564, https://doi.org/10.5194/acp-23-13555-2023, https://doi.org/10.5194/acp-23-13555-2023, 2023
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Iason Markantonis, Diamando Vlachogiannis, Athanasios Sfetsos, Ioannis Kioutsioukis, and Nadia Politi
Adv. Sci. Res., 19, 145–158, https://doi.org/10.5194/asr-19-145-2023, https://doi.org/10.5194/asr-19-145-2023, 2023
Short summary
Short summary
This paper examines the simulataneous exceedance of daily accumulated precipitation (RR) and minimum (TN) temperature thresholds in Greece for the period 1980–2004 and for each month in the period November to April. Available data from observations and projection simulations are used to calculate the probabilities of extreme wet-cold compound events at the past. Models are validated by the observational data.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Iason Markantonis, Diamando Vlachogiannis, Athanasios Sfetsos, and Ioannis Kioutsioukis
Earth Syst. Dynam., 13, 1491–1504, https://doi.org/10.5194/esd-13-1491-2022, https://doi.org/10.5194/esd-13-1491-2022, 2022
Short summary
Short summary
This work focuses on the study of daily wet–cold compound events in Greece in the period November–April. We firstly study the historic period 1980–2004 in which we validate projection models with observations. Then we compare the model results with future period 2025–2049 RCP4.5 and RCP8.5 scenarios. The aim of the study is to calculate the probability of the events and to locate the areas where those are higher and how the probabilities will change at the future.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Stefano Galmarini, Paul Makar, Olivia E. Clifton, Christian Hogrefe, Jesse O. Bash, Roberto Bellasio, Roberto Bianconi, Johannes Bieser, Tim Butler, Jason Ducker, Johannes Flemming, Alma Hodzic, Christopher D. Holmes, Ioannis Kioutsioukis, Richard Kranenburg, Aurelia Lupascu, Juan Luis Perez-Camanyo, Jonathan Pleim, Young-Hee Ryu, Roberto San Jose, Donna Schwede, Sam Silva, and Ralf Wolke
Atmos. Chem. Phys., 21, 15663–15697, https://doi.org/10.5194/acp-21-15663-2021, https://doi.org/10.5194/acp-21-15663-2021, 2021
Short summary
Short summary
This technical note presents the research protocols for phase 4 of the Air Quality Model Evaluation International Initiative (AQMEII4). This initiative has three goals: (i) to define the state of wet and dry deposition in regional models, (ii) to evaluate how dry deposition influences air concentration and flux predictions, and (iii) to identify the causes for prediction differences. The evaluation compares LULC-specific dry deposition and effective conductances and fluxes.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Dana L. McGuffin, Yuanlong Huang, Richard C. Flagan, Tuukka Petäjä, B. Erik Ydstie, and Peter J. Adams
Geosci. Model Dev., 14, 1821–1839, https://doi.org/10.5194/gmd-14-1821-2021, https://doi.org/10.5194/gmd-14-1821-2021, 2021
Short summary
Short summary
Atmospheric particle formation, emissions, and growth process rates are significant sources of uncertainty in predicting climate change. We aim to reduce that uncertainty by using measurements from several ground-based sites across Europe. We developed an estimation technique to adapt the governing process rates so model–measurement bias decays. The estimation framework developed has potential to improve model predictions while providing insight into the underlying atmospheric particle physics.
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
Short summary
Short summary
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.
Antonios Tasoglou, Evangelos Louvaris, Kalliopi Florou, Aikaterini Liangou, Eleni Karnezi, Christos Kaltsonoudis, Ningxin Wang, and Spyros N. Pandis
Atmos. Chem. Phys., 20, 11625–11637, https://doi.org/10.5194/acp-20-11625-2020, https://doi.org/10.5194/acp-20-11625-2020, 2020
Short summary
Short summary
A month-long set of summertime measurements in a remote area in the Mediterranean is used to quantify aerosol absorption. The measured light absorption was two or more times higher than that of fresh black carbon. The absorption enhancement due to the coating of black carbon cores by other aerosol components could explain only part of this absorption enhancement. The rest was due to brown carbon, mostly in the form of extremely low volatility organic compounds.
Quanyang Lu, Benjamin N. Murphy, Momei Qin, Peter J. Adams, Yunliang Zhao, Havala O. T. Pye, Christos Efstathiou, Chris Allen, and Allen L. Robinson
Atmos. Chem. Phys., 20, 4313–4332, https://doi.org/10.5194/acp-20-4313-2020, https://doi.org/10.5194/acp-20-4313-2020, 2020
Short summary
Short summary
This research work investigates organic aerosol formation in California during the CalNex study. We update the chemical transport model with the most recent mobile-source emission data and introduce a simple parameterization for secondary organic aerosol formed from intermediate-volatility organic compounds. Our results highlight the important contribution of IVOCs to SOA production in the Los Angeles region but underscore that other uncertainties must be addressed to close the SOA mass balance.
Athanasios Nenes, Spyros N. Pandis, Rodney J. Weber, and Armistead Russell
Atmos. Chem. Phys., 20, 3249–3258, https://doi.org/10.5194/acp-20-3249-2020, https://doi.org/10.5194/acp-20-3249-2020, 2020
Short summary
Short summary
We show that aerosol acidity (pH) and liquid water content naturally emerge as previously ignored parameters that drive particulate matter formation in the atmosphere, and its sensitivity to emissions of ammonia and nitric acid. The simple framework presented is easily applied to ambient measurements or model output, and it provides the
chemical regimeof PM sensitivity to ammonia and nitric acid availability.
Weiqi Xu, Conghui Xie, Eleni Karnezi, Qi Zhang, Junfeng Wang, Spyros N. Pandis, Xinlei Ge, Jingwei Zhang, Junling An, Qingqing Wang, Jian Zhao, Wei Du, Yanmei Qiu, Wei Zhou, Yao He, Ying Li, Jie Li, Pingqing Fu, Zifa Wang, Douglas R. Worsnop, and Yele Sun
Atmos. Chem. Phys., 19, 10205–10216, https://doi.org/10.5194/acp-19-10205-2019, https://doi.org/10.5194/acp-19-10205-2019, 2019
Short summary
Short summary
We present the first aerosol volatility measurements in Beijing in summer using a thermodenuder coupled with aerosol mass spectrometers. Our results showed that organic aerosol (OA) comprised mainly semi-volatile organic compounds in summer, and the freshly oxidized secondary OA was the most volatile component. We also found quite different volatility distributions in black-carbon-containing primary and secondary OA, ambient OA, ambient secondary OA and the WRF-Chem model.
Christos Kaltsonoudis, Spiro D. Jorga, Evangelos Louvaris, Kalliopi Florou, and Spyros N. Pandis
Atmos. Meas. Tech., 12, 2733–2743, https://doi.org/10.5194/amt-12-2733-2019, https://doi.org/10.5194/amt-12-2733-2019, 2019
Short summary
Short summary
A portable dual-smog-chamber system was developed using two identical pillow-shaped smog chambers surrounded by UV lamps. The system has been designed to use ambient air as the starting point of the experiments. It can be easily disassembled and transported, enabling the study of various atmospheric environments and it can be used with natural sunlight. The results of test experiments using ambient air are discussed as examples of applications of this system.
Katerina S. Karadima, Vlasis G. Mavrantzas, and Spyros N. Pandis
Atmos. Chem. Phys., 19, 5571–5587, https://doi.org/10.5194/acp-19-5571-2019, https://doi.org/10.5194/acp-19-5571-2019, 2019
Short summary
Short summary
We explore the morphologies of multicomponent nanoparticles through atomistic molecular dynamics simulations under atmospherically relevant conditions. Phase separation is predicted for almost all simulated nanoparticles either between organics and inorganics or between hydrophobic and hydrophilic constituents. Three main particle types were identified: organic islands at the surface, inorganic core-organic shell morphologies and complex structures with hydrophobic and hydrophilic domains.
Georgia N. Theodoritsi and Spyros N. Pandis
Atmos. Chem. Phys., 19, 5403–5415, https://doi.org/10.5194/acp-19-5403-2019, https://doi.org/10.5194/acp-19-5403-2019, 2019
Short summary
Short summary
The chemical transport model PMCAMx was extended to investigate the effects of partitioning and photochemical aging of biomass burning emissions on organic aerosol (OA) concentrations and was applied in Europe. During the summer, the contribution of biomass burning to total OA levels over continental Europe was 16 % and during winter 47 %. Intermediate volatility organic compounds are predicted to be important precursors of secondary OA from biomass burning.
Anthoula D. Drosatou, Ksakousti Skyllakou, Georgia N. Theodoritsi, and Spyros N. Pandis
Atmos. Chem. Phys., 19, 973–986, https://doi.org/10.5194/acp-19-973-2019, https://doi.org/10.5194/acp-19-973-2019, 2019
Short summary
Short summary
The ability of positive matrix factorization (PMF) factor analysis to identify and quantify the organic aerosol (OA) sources accurately is tested in this modeling study. The estimated uncertainty of the contribution of fresh biomass burning is less than 30 % and of the other primary sources is less than 40 %, when these sources contribute more than 20 % to the OA. Τhe first oxygenated OA factor includes mainly highly aged OA, while the second oxygenated OA factor contains fresher secondary OA.
Ningxin Wang, Spiro D. Jorga, Jeffery R. Pierce, Neil M. Donahue, and Spyros N. Pandis
Atmos. Meas. Tech., 11, 6577–6588, https://doi.org/10.5194/amt-11-6577-2018, https://doi.org/10.5194/amt-11-6577-2018, 2018
Short summary
Short summary
The interaction of particles with the chamber walls has been a significant source of uncertainty when analyzing results of secondary organic aerosol formation experiments performed in Teflon chambers. We evaluated the performance of several particle wall-loss correction methods for aging experiments of α-pinene ozonolysis products. Experimental procedures are proposed for the characterization of particle losses during different stages of these experiments.
Marina Astitha, Ioannis Kioutsioukis, Ghezae Araya Fisseha, Roberto Bianconi, Johannes Bieser, Jesper H. Christensen, Owen R. Cooper, Stefano Galmarini, Christian Hogrefe, Ulas Im, Bryan Johnson, Peng Liu, Uarporn Nopmongcol, Irina Petropavlovskikh, Efisio Solazzo, David W. Tarasick, and Greg Yarwood
Atmos. Chem. Phys., 18, 13925–13945, https://doi.org/10.5194/acp-18-13925-2018, https://doi.org/10.5194/acp-18-13925-2018, 2018
Short summary
Short summary
This work is unique in the detailed analyses of modeled ozone vertical profiles from sites in North America through the collaboration of four research groups from the US and EU. We assess the air quality models' performance and model inter-comparison for ozone vertical profiles and stratospheric ozone intrusions. Lastly, we designate the important role of lateral boundary conditions in the ozone vertical profiles using chemically inert tracers.
David Patoulias, Christos Fountoukis, Ilona Riipinen, Ari Asmi, Markku Kulmala, and Spyros N. Pandis
Atmos. Chem. Phys., 18, 13639–13654, https://doi.org/10.5194/acp-18-13639-2018, https://doi.org/10.5194/acp-18-13639-2018, 2018
Short summary
Short summary
PMCAMx-UF, a 3-D chemical transport model focusing on the simulation of ultrafine particles, has been extended with the addition of the volatility basis set (VBS) approach for the simulation of organic aerosol. The model was applied in Europe and its predictions were evaluated against field observations collected during the PEGASOS 2012 campaign. The condensation of organics led to an increase (50–120 %) in the larger particles but the total number concentration decreased by 10–30 %.
Alexandra P. Tsimpidi, Vlassis A. Karydis, Andrea Pozzer, Spyros N. Pandis, and Jos Lelieveld
Geosci. Model Dev., 11, 3369–3389, https://doi.org/10.5194/gmd-11-3369-2018, https://doi.org/10.5194/gmd-11-3369-2018, 2018
Short summary
Short summary
A new module, ORACLE 2-D, that calculates the concentrations of surrogate organic species in two-dimensional space defined by volatility and oxygen-to-carbon ratio has been developed and evaluated. ORACLE 2-D uses a simple photochemical aging scheme that efficiently simulates the net effects of fragmentation and functionalization. ORACLE 2-D can be used to compute the ability of organic particles to act as cloud condensation nuclei and serves as a tool to quantify their climatic impact.
Eleni Karnezi, Benjamin N. Murphy, Laurent Poulain, Hartmut Herrmann, Alfred Wiedensohler, Florian Rubach, Astrid Kiendler-Scharr, Thomas F. Mentel, and Spyros N. Pandis
Atmos. Chem. Phys., 18, 10759–10772, https://doi.org/10.5194/acp-18-10759-2018, https://doi.org/10.5194/acp-18-10759-2018, 2018
Short summary
Short summary
Different parameterizations of the organic aerosol (OA) formation and evolution are evaluated using ground and airborne measurements collected in the 2012 PEGASOS field campaign in the Po Valley (Italy). Total OA concentration and O : C ratios were reproduced within experimental error by a number of schemes. Anthropogenic secondary OA (SOA) contributed 15–25 % of the total OA, 20–35 % of SOA from intermediate volatility compounds oxidation, and 15–45 % of biogenic SOA depending on the scheme.
Stefano Galmarini, Ioannis Kioutsioukis, Efisio Solazzo, Ummugulsum Alyuz, Alessandra Balzarini, Roberto Bellasio, Anna M. K. Benedictow, Roberto Bianconi, Johannes Bieser, Joergen Brandt, Jesper H. Christensen, Augustin Colette, Gabriele Curci, Yanko Davila, Xinyi Dong, Johannes Flemming, Xavier Francis, Andrea Fraser, Joshua Fu, Daven K. Henze, Christian Hogrefe, Ulas Im, Marta Garcia Vivanco, Pedro Jiménez-Guerrero, Jan Eiof Jonson, Nutthida Kitwiroon, Astrid Manders, Rohit Mathur, Laura Palacios-Peña, Guido Pirovano, Luca Pozzoli, Marie Prank, Martin Schultz, Rajeet S. Sokhi, Kengo Sudo, Paolo Tuccella, Toshihiko Takemura, Takashi Sekiya, and Alper Unal
Atmos. Chem. Phys., 18, 8727–8744, https://doi.org/10.5194/acp-18-8727-2018, https://doi.org/10.5194/acp-18-8727-2018, 2018
Short summary
Short summary
An ensemble of model results relating to ozone concentrations in Europe in 2010 has been produced and studied. The novelty consists in the fact that the ensemble is made of results of models working at two different scales (regional and global), therefore contributing in detail two different parts of the atmospheric spectrum. The ensemble defined as a hybrid has been studied in detail and shown to bring additional value to the assessment of air quality.
Ulas Im, Jørgen Brandt, Camilla Geels, Kaj Mantzius Hansen, Jesper Heile Christensen, Mikael Skou Andersen, Efisio Solazzo, Ioannis Kioutsioukis, Ummugulsum Alyuz, Alessandra Balzarini, Rocio Baro, Roberto Bellasio, Roberto Bianconi, Johannes Bieser, Augustin Colette, Gabriele Curci, Aidan Farrow, Johannes Flemming, Andrea Fraser, Pedro Jimenez-Guerrero, Nutthida Kitwiroon, Ciao-Kai Liang, Uarporn Nopmongcol, Guido Pirovano, Luca Pozzoli, Marje Prank, Rebecca Rose, Ranjeet Sokhi, Paolo Tuccella, Alper Unal, Marta Garcia Vivanco, Jason West, Greg Yarwood, Christian Hogrefe, and Stefano Galmarini
Atmos. Chem. Phys., 18, 5967–5989, https://doi.org/10.5194/acp-18-5967-2018, https://doi.org/10.5194/acp-18-5967-2018, 2018
Short summary
Short summary
The impacts of air pollution on human health and their costs in Europe and the United States for the year 2010 ared modeled by a multi-model ensemble. In Europe, the number of premature deaths is calculated to be 414 000, while in the US it is estimated to be 160 000. Health impacts estimated by individual models can vary up to a factor of 3. Results show that the domestic emissions have the largest impact on premature deaths, compared to foreign sources.
Evangelia Kostenidou, Eleni Karnezi, James R. Hite Jr., Aikaterini Bougiatioti, Kate Cerully, Lu Xu, Nga L. Ng, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 18, 5799–5819, https://doi.org/10.5194/acp-18-5799-2018, https://doi.org/10.5194/acp-18-5799-2018, 2018
Short summary
Short summary
The volatility distribution of organic aerosol (OA) and its sources during the Southern Oxidant and Aerosol Study (SOAS) was estimated. The volatility distribution of all components covered a wide range including both semi-volatile and low-volatility components. The oxygen content of the factors can be combined with their estimated volatility and hygroscopicity to provide a better view of their physical properties.
Ningxin Wang, Evangelia Kostenidou, Neil M. Donahue, and Spyros N. Pandis
Atmos. Chem. Phys., 18, 3589–3601, https://doi.org/10.5194/acp-18-3589-2018, https://doi.org/10.5194/acp-18-3589-2018, 2018
Short summary
Short summary
This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. After an equivalent of 2–4 days of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase in the organic aerosol concentration and an increase in aerosol O : C by up to 0.04. The relative humidity in the 5–50 % range had a minimum effect on aging.
Kerrigan P. Cain and Spyros N. Pandis
Atmos. Meas. Tech., 10, 4865–4876, https://doi.org/10.5194/amt-10-4865-2017, https://doi.org/10.5194/amt-10-4865-2017, 2017
Short summary
Short summary
Hygroscopicity, oxidation level, and volatility of organic pollutants are three crucial properties that determine their fate in the atmosphere. This study assesses the feasibility of a novel measurement and analysis technique to determine these properties of organic aerosol
components at the same time and to establish their relationship.
Evangelos E. Louvaris, Eleni Karnezi, Evangelia Kostenidou, Christos Kaltsonoudis, and Spyros N. Pandis
Atmos. Meas. Tech., 10, 3909–3918, https://doi.org/10.5194/amt-10-3909-2017, https://doi.org/10.5194/amt-10-3909-2017, 2017
Short summary
Short summary
A method for the determination of the organic aerosol volatility distribution combining thermodenuder and isothermal dilution measurements is developed. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol produced during meat charbroiling. Addition of the dilution measurements to the thermodenuder data results in a lower uncertainty of the estimated vaporization enthalpy as well as the semivolatile content of the aerosol.
Alexandra P. Tsimpidi, Vlassis A. Karydis, Spyros N. Pandis, and Jos Lelieveld
Atmos. Chem. Phys., 17, 7345–7364, https://doi.org/10.5194/acp-17-7345-2017, https://doi.org/10.5194/acp-17-7345-2017, 2017
Short summary
Short summary
We analyzed the sensitivity of model-predicted global-scale OA to parameters and assumptions that control primary emissions, photochemical aging, and the scavenging efficiency of LVOCs, SVOCs, and IVOCs. The simulated OA concentrations were evaluated against a global dataset of AMS measurements. According to our analysis, a combination of increased IVOCs and decreased hygroscopicity of the freshly emitted IVOCs can help reduce discrepancies between simulated SOA and observed OOA concentrations.
Christos Kaltsonoudis, Evangelia Kostenidou, Evangelos Louvaris, Magda Psichoudaki, Epameinondas Tsiligiannis, Kalliopi Florou, Aikaterini Liangou, and Spyros N. Pandis
Atmos. Chem. Phys., 17, 7143–7155, https://doi.org/10.5194/acp-17-7143-2017, https://doi.org/10.5194/acp-17-7143-2017, 2017
Short summary
Short summary
Cooking emissions can be a significant source of particulate matter in urban areas. In this study the aerosol- and gas-phase emissions from meat charbroiling were characterized. More than 99% of the aerosol emitted was composed of organic compounds. The fresh particles were similar to the cooking organic aerosol over Greek cities during the winter, while the reacted particles were similar to those found in the atmosphere during the summer.
Kalliopi Florou, Dimitrios K. Papanastasiou, Michael Pikridas, Christos Kaltsonoudis, Evangelos Louvaris, Georgios I. Gkatzelis, David Patoulias, Nikolaos Mihalopoulos, and Spyros N. Pandis
Atmos. Chem. Phys., 17, 3145–3163, https://doi.org/10.5194/acp-17-3145-2017, https://doi.org/10.5194/acp-17-3145-2017, 2017
Short summary
Short summary
The composition of fine particulate matter (PM) in two major Greek cities (Athens and Patras) was measured during two wintertime campaigns in 2012 and 2013. Residential wood burning has dramatically increased due to the Greek financial crisis, contributing around 50 % of the fine PM on average and more than 80 % during nighttime. Cooking is also an important source during both midday and evening, while transportation dominates only during the morning rush hour.
Ioannis Kioutsioukis, Ulas Im, Efisio Solazzo, Roberto Bianconi, Alba Badia, Alessandra Balzarini, Rocío Baró, Roberto Bellasio, Dominik Brunner, Charles Chemel, Gabriele Curci, Hugo Denier van der Gon, Johannes Flemming, Renate Forkel, Lea Giordano, Pedro Jiménez-Guerrero, Marcus Hirtl, Oriol Jorba, Astrid Manders-Groot, Lucy Neal, Juan L. Pérez, Guidio Pirovano, Roberto San Jose, Nicholas Savage, Wolfram Schroder, Ranjeet S. Sokhi, Dimiter Syrakov, Paolo Tuccella, Johannes Werhahn, Ralf Wolke, Christian Hogrefe, and Stefano Galmarini
Atmos. Chem. Phys., 16, 15629–15652, https://doi.org/10.5194/acp-16-15629-2016, https://doi.org/10.5194/acp-16-15629-2016, 2016
Short summary
Short summary
Four ensemble methods are applied to two annual AQMEII datasets and their performance is compared for O3, NO2 and PM10. The goal of the study is to quantify to what extent we can extract predictable signals from an ensemble with superior skill at each station over the single models and the ensemble mean. The promotion of the right amount of accuracy and diversity within the ensemble results in an average additional skill of up to 31 % compared to using the full ensemble in an unconditional way.
Christos Kaltsonoudis, Evangelia Kostenidou, Kalliopi Florou, Magda Psichoudaki, and Spyros N. Pandis
Atmos. Chem. Phys., 16, 14825–14842, https://doi.org/10.5194/acp-16-14825-2016, https://doi.org/10.5194/acp-16-14825-2016, 2016
Short summary
Short summary
Volatile organic compounds (VOCs) were monitored in urban backgrounds sites, in Athens and Patras in Greece. In summer most of the measured VOCs were due to biogenic and traffic emissions. Winter measurements in Athens revealed that biomass burning used for residential heating was the dominant VOC source. The biomass burning VOC emission ratios and emission factors were estimated.
Antigoni Panagiotopoulou, Panagiotis Charalampidis, Christos Fountoukis, Christodoulos Pilinis, and Spyros N. Pandis
Geosci. Model Dev., 9, 4257–4272, https://doi.org/10.5194/gmd-9-4257-2016, https://doi.org/10.5194/gmd-9-4257-2016, 2016
Short summary
Short summary
The ability of chemical transport model PMCAMx to reproduce ground and satellite aerosol optical depth (AOD) measurements over Europe is evaluated. PMCAMx reproduces AOD values over Spain, the UK, central Europe, and Russia with a fractional bias of less than 15 % and a fractional error of less than 30 %. The model overestimates the AOD over northern Europe probably due to an overestimation of organic aerosol and sulfates, and underestimates over the Balkans due to an underestimation of sulfates.
Elham Baranizadeh, Benjamin N. Murphy, Jan Julin, Saeed Falahat, Carly L. Reddington, Antti Arola, Lars Ahlm, Santtu Mikkonen, Christos Fountoukis, David Patoulias, Andreas Minikin, Thomas Hamburger, Ari Laaksonen, Spyros N. Pandis, Hanna Vehkamäki, Kari E. J. Lehtinen, and Ilona Riipinen
Geosci. Model Dev., 9, 2741–2754, https://doi.org/10.5194/gmd-9-2741-2016, https://doi.org/10.5194/gmd-9-2741-2016, 2016
Short summary
Short summary
The molecular mechanisms through which new ultrafine (< 100 nm) aerosol particles are formed in the atmosphere have puzzled the scientific community for decades. In the past few years, however, significant progress has been made in unraveling these processes through laboratory studies and computational efforts. In this work we have implemented these new developments to an air quality model and study the implications of anthropogenically driven particle formation for European air quality.
Alexandra P. Tsimpidi, Vlassis A. Karydis, Spyros N. Pandis, and Jos Lelieveld
Atmos. Chem. Phys., 16, 8939–8962, https://doi.org/10.5194/acp-16-8939-2016, https://doi.org/10.5194/acp-16-8939-2016, 2016
Short summary
Short summary
In this work we use a global chemistry climate model together with a comprehensive global AMS data set in order to provide valuable insights into the temporal and geographical variability of the contribution of the emitted particles and the chemically processed organic material from combustion sources to total OA. This study reveals the high importance of SOA from anthropogenic sources on global OA concentrations and identifies plausible sources of discrepancy between models and measurements.
Christos Fountoukis, Athanasios G. Megaritis, Ksakousti Skyllakou, Panagiotis E. Charalampidis, Hugo A. C. Denier van der Gon, Monica Crippa, André S. H. Prévôt, Friederike Fachinger, Alfred Wiedensohler, Christodoulos Pilinis, and Spyros N. Pandis
Atmos. Chem. Phys., 16, 3727–3741, https://doi.org/10.5194/acp-16-3727-2016, https://doi.org/10.5194/acp-16-3727-2016, 2016
Short summary
Short summary
We use PMCAMx with high grid resolution over Paris to simulate carbonaceous aerosol during the summer and winter MEGAPOLI campaigns. PMCAMx reproduces BC observations well. Addition of cooking organic aerosol emissions of 80 mg per day per capita is needed to reproduce the corresponding observations. While the oxygenated organic aerosol predictions during the summer are encouraging a major wintertime source appears to be missing.
Andrea Paciga, Eleni Karnezi, Evangelia Kostenidou, Lea Hildebrandt, Magda Psichoudaki, Gabriella J. Engelhart, Byong-Hyoek Lee, Monica Crippa, André S. H. Prévôt, Urs Baltensperger, and Spyros N. Pandis
Atmos. Chem. Phys., 16, 2013–2023, https://doi.org/10.5194/acp-16-2013-2016, https://doi.org/10.5194/acp-16-2013-2016, 2016
Short summary
Short summary
We estimate the volatility distribution for the organic aerosol (OA) components during summer and winter field campaigns in Paris, France as part of the collaborative project MEGAPOLI. The OA factors (hydrocarbon like OA, cooking OA, marine OA, oxygenated OA) had a broad spectrum of volatilities with no direct link between the average volatility and average oxygen to carbon of the OA components.
G. I. Gkatzelis, D. K. Papanastasiou, K. Florou, C. Kaltsonoudis, E. Louvaris, and S. N. Pandis
Atmos. Meas. Tech., 9, 103–114, https://doi.org/10.5194/amt-9-103-2016, https://doi.org/10.5194/amt-9-103-2016, 2016
Short summary
Short summary
A method for the measurement of the nonvolatile atmospheric particle size distribution is developed and tested. The tests include laboratory experiments with biogenic and anthropogenic secondary organic aerosol as well as nucleation experiments with ambient air. The method is then further tested during an ambient campaign.
E. Kostenidou, K. Florou, C. Kaltsonoudis, M. Tsiflikiotou, S. Vratolis, K. Eleftheriadis, and S. N. Pandis
Atmos. Chem. Phys., 15, 11355–11371, https://doi.org/10.5194/acp-15-11355-2015, https://doi.org/10.5194/acp-15-11355-2015, 2015
Short summary
Short summary
The concentration and chemical composition of fine particulate matter were measured during the summer of 2012 in two Greek cities, Patras and Athens. The composition of PM1 was surprisingly similar in both areas, demonstrating the importance of regional sources. Analysis of the Aerosol Mass Spectrometer data suggested that the contribution of the primary sources to organic aerosol was important (22% in Patras and 35% in Athens) but not dominant.
M. Pikridas, J. Sciare, F. Freutel, S. Crumeyrolle, S.-L. von der Weiden-Reinmüller, A. Borbon, A. Schwarzenboeck, M. Merkel, M. Crippa, E. Kostenidou, M. Psichoudaki, L. Hildebrandt, G. J. Engelhart, T. Petäjä, A. S. H. Prévôt, F. Drewnick, U. Baltensperger, A. Wiedensohler, M. Kulmala, M. Beekmann, and S. N. Pandis
Atmos. Chem. Phys., 15, 10219–10237, https://doi.org/10.5194/acp-15-10219-2015, https://doi.org/10.5194/acp-15-10219-2015, 2015
Short summary
Short summary
Aerosol size distribution measurements from three ground sites, two mobile laboratories, and one airplane are combined to investigate the spatial and temporal variability of ultrafine particles in and around Paris during the summer and winter MEGAPOLI campaigns. The role of nucleation as a particle source and the influence of Paris emissions on their surroundings are examined.
M. Beekmann, A. S. H. Prévôt, F. Drewnick, J. Sciare, S. N. Pandis, H. A. C. Denier van der Gon, M. Crippa, F. Freutel, L. Poulain, V. Ghersi, E. Rodriguez, S. Beirle, P. Zotter, S.-L. von der Weiden-Reinmüller, M. Bressi, C. Fountoukis, H. Petetin, S. Szidat, J. Schneider, A. Rosso, I. El Haddad, A. Megaritis, Q. J. Zhang, V. Michoud, J. G. Slowik, S. Moukhtar, P. Kolmonen, A. Stohl, S. Eckhardt, A. Borbon, V. Gros, N. Marchand, J. L. Jaffrezo, A. Schwarzenboeck, A. Colomb, A. Wiedensohler, S. Borrmann, M. Lawrence, A. Baklanov, and U. Baltensperger
Atmos. Chem. Phys., 15, 9577–9591, https://doi.org/10.5194/acp-15-9577-2015, https://doi.org/10.5194/acp-15-9577-2015, 2015
Short summary
Short summary
A detailed characterization of air quality in the Paris (France) agglomeration, a megacity, during two summer and winter intensive campaigns and from additional 1-year observations, revealed that about 70% of the fine particulate matter (PM) at urban background is transported into the megacity from upwind regions. Unexpectedly, a major part of organic PM is of modern origin (woodburning and cooking activities, secondary formation from biogenic VOC).
S. Fuzzi, U. Baltensperger, K. Carslaw, S. Decesari, H. Denier van der Gon, M. C. Facchini, D. Fowler, I. Koren, B. Langford, U. Lohmann, E. Nemitz, S. Pandis, I. Riipinen, Y. Rudich, M. Schaap, J. G. Slowik, D. V. Spracklen, E. Vignati, M. Wild, M. Williams, and S. Gilardoni
Atmos. Chem. Phys., 15, 8217–8299, https://doi.org/10.5194/acp-15-8217-2015, https://doi.org/10.5194/acp-15-8217-2015, 2015
Short summary
Short summary
Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last 2 decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and the effects of PM on human health and the environment.
L. Hildebrandt Ruiz, A. L. Paciga, K. M. Cerully, A. Nenes, N. M. Donahue, and S. N. Pandis
Atmos. Chem. Phys., 15, 8301–8313, https://doi.org/10.5194/acp-15-8301-2015, https://doi.org/10.5194/acp-15-8301-2015, 2015
Short summary
Short summary
Secondary organic aerosol (SOA) is transformed after its initial formation. We explored the effects of this chemical aging on the composition, mass yield, volatility, and hygroscopicity of SOA formed from the photo-oxidation of small aromatic volatile organic compounds. Higher exposure to the hydroxyl radical resulted in different SOA composition, average carbon oxidation state, and mass yield. The vapor pressure of SOA formed under different conditions varied by as much as a factor of 30.
D. Patoulias, C. Fountoukis, I. Riipinen, and S. N. Pandis
Atmos. Chem. Phys., 15, 6337–6350, https://doi.org/10.5194/acp-15-6337-2015, https://doi.org/10.5194/acp-15-6337-2015, 2015
Short summary
Short summary
A new aerosol dynamics model (DMANx) describing the organic vapor condensation on nanoparticles based on the volatility basis set framework is used to simulate typical nucleation events in two contrasting environments in Hyytiälä (Finland) and Finokalia (Greece). The role of semivolatile, low, and extremely low volatility organics and the corresponding surface energies is investigated.
I. Riipinen, N. Rastak, and S. N. Pandis
Atmos. Chem. Phys., 15, 6305–6322, https://doi.org/10.5194/acp-15-6305-2015, https://doi.org/10.5194/acp-15-6305-2015, 2015
Short summary
Short summary
Atmospheric organic aerosol is complex and thus a challenge to model. We introduce a theoretical framework (solubility distributions) to represent the solubility of multicomponent mixtures. Using the framework, we evaluate the commonly made assumptions about the cloud condensation nucleus (CCN) activity of organic mixtures. We find that material with water solubilities larger than 0.1-100 g/L can usually be treated as completely soluble, which simplifies the treatment of organic CCN.
A. Tasoglou and S. N. Pandis
Atmos. Chem. Phys., 15, 6035–6046, https://doi.org/10.5194/acp-15-6035-2015, https://doi.org/10.5194/acp-15-6035-2015, 2015
A. P. Tsimpidi, V. A. Karydis, A. Pozzer, S. N. Pandis, and J. Lelieveld
Geosci. Model Dev., 7, 3153–3172, https://doi.org/10.5194/gmd-7-3153-2014, https://doi.org/10.5194/gmd-7-3153-2014, 2014
Short summary
Short summary
A computationally efficient module for the description of OA composition and evolution in the atmosphere has been developed. This module subdivides OA into several compounds based on their source of origin and volatility, allowing the quantification of POA vs. SOA as well as biogenic vs. anthropogenic contributions to OA concentrations. Such fundamental information can shed light on long-term changes in OA abundance, and hence project the effects of OA on future air quality and climate.
I. Kioutsioukis and S. Galmarini
Atmos. Chem. Phys., 14, 11791–11815, https://doi.org/10.5194/acp-14-11791-2014, https://doi.org/10.5194/acp-14-11791-2014, 2014
A. G. Megaritis, C. Fountoukis, P. E. Charalampidis, H. A. C. Denier van der Gon, C. Pilinis, and S. N. Pandis
Atmos. Chem. Phys., 14, 10283–10298, https://doi.org/10.5194/acp-14-10283-2014, https://doi.org/10.5194/acp-14-10283-2014, 2014
E. Karnezi, I. Riipinen, and S. N. Pandis
Atmos. Meas. Tech., 7, 2953–2965, https://doi.org/10.5194/amt-7-2953-2014, https://doi.org/10.5194/amt-7-2953-2014, 2014
C. Fountoukis, A. G. Megaritis, K. Skyllakou, P. E. Charalampidis, C. Pilinis, H. A. C. Denier van der Gon, M. Crippa, F. Canonaco, C. Mohr, A. S. H. Prévôt, J. D. Allan, L. Poulain, T. Petäjä, P. Tiitta, S. Carbone, A. Kiendler-Scharr, E. Nemitz, C. O'Dowd, E. Swietlicki, and S. N. Pandis
Atmos. Chem. Phys., 14, 9061–9076, https://doi.org/10.5194/acp-14-9061-2014, https://doi.org/10.5194/acp-14-9061-2014, 2014
M. Crippa, F. Canonaco, V. A. Lanz, M. Äijälä, J. D. Allan, S. Carbone, G. Capes, D. Ceburnis, M. Dall'Osto, D. A. Day, P. F. DeCarlo, M. Ehn, A. Eriksson, E. Freney, L. Hildebrandt Ruiz, R. Hillamo, J. L. Jimenez, H. Junninen, A. Kiendler-Scharr, A.-M. Kortelainen, M. Kulmala, A. Laaksonen, A. A. Mensah, C. Mohr, E. Nemitz, C. O'Dowd, J. Ovadnevaite, S. N. Pandis, T. Petäjä, L. Poulain, S. Saarikoski, K. Sellegri, E. Swietlicki, P. Tiitta, D. R. Worsnop, U. Baltensperger, and A. S. H. Prévôt
Atmos. Chem. Phys., 14, 6159–6176, https://doi.org/10.5194/acp-14-6159-2014, https://doi.org/10.5194/acp-14-6159-2014, 2014
B. N. Murphy, N. M. Donahue, A. L. Robinson, and S. N. Pandis
Atmos. Chem. Phys., 14, 5825–5839, https://doi.org/10.5194/acp-14-5825-2014, https://doi.org/10.5194/acp-14-5825-2014, 2014
A. Bougiatioti, I. Stavroulas, E. Kostenidou, P. Zarmpas, C. Theodosi, G. Kouvarakis, F. Canonaco, A. S. H. Prévôt, A. Nenes, S. N. Pandis, and N. Mihalopoulos
Atmos. Chem. Phys., 14, 4793–4807, https://doi.org/10.5194/acp-14-4793-2014, https://doi.org/10.5194/acp-14-4793-2014, 2014
K. Skyllakou, B. N. Murphy, A. G. Megaritis, C. Fountoukis, and S. N. Pandis
Atmos. Chem. Phys., 14, 2343–2352, https://doi.org/10.5194/acp-14-2343-2014, https://doi.org/10.5194/acp-14-2343-2014, 2014
L. Ahlm, J. Julin, C. Fountoukis, S. N. Pandis, and I. Riipinen
Atmos. Chem. Phys., 13, 10271–10283, https://doi.org/10.5194/acp-13-10271-2013, https://doi.org/10.5194/acp-13-10271-2013, 2013
E. Kostenidou, C. Kaltsonoudis, M. Tsiflikiotou, E. Louvaris, L. M. Russell, and S. N. Pandis
Atmos. Chem. Phys., 13, 8797–8811, https://doi.org/10.5194/acp-13-8797-2013, https://doi.org/10.5194/acp-13-8797-2013, 2013
E. Solazzo, A. Riccio, I. Kioutsioukis, and S. Galmarini
Atmos. Chem. Phys., 13, 8315–8333, https://doi.org/10.5194/acp-13-8315-2013, https://doi.org/10.5194/acp-13-8315-2013, 2013
S. Galmarini, I. Kioutsioukis, and E. Solazzo
Atmos. Chem. Phys., 13, 7153–7182, https://doi.org/10.5194/acp-13-7153-2013, https://doi.org/10.5194/acp-13-7153-2013, 2013
Q. J. Zhang, M. Beekmann, F. Drewnick, F. Freutel, J. Schneider, M. Crippa, A. S. H. Prevot, U. Baltensperger, L. Poulain, A. Wiedensohler, J. Sciare, V. Gros, A. Borbon, A. Colomb, V. Michoud, J.-F. Doussin, H. A. C. Denier van der Gon, M. Haeffelin, J.-C. Dupont, G. Siour, H. Petetin, B. Bessagnet, S. N. Pandis, A. Hodzic, O. Sanchez, C. Honoré, and O. Perrussel
Atmos. Chem. Phys., 13, 5767–5790, https://doi.org/10.5194/acp-13-5767-2013, https://doi.org/10.5194/acp-13-5767-2013, 2013
E. Athanasopoulou, H. Vogel, B. Vogel, A. P. Tsimpidi, S. N. Pandis, C. Knote, and C. Fountoukis
Atmos. Chem. Phys., 13, 625–645, https://doi.org/10.5194/acp-13-625-2013, https://doi.org/10.5194/acp-13-625-2013, 2013
V.-M. Kerminen, M. Paramonov, T. Anttila, I. Riipinen, C. Fountoukis, H. Korhonen, E. Asmi, L. Laakso, H. Lihavainen, E. Swietlicki, B. Svenningsson, A. Asmi, S. N. Pandis, M. Kulmala, and T. Petäjä
Atmos. Chem. Phys., 12, 12037–12059, https://doi.org/10.5194/acp-12-12037-2012, https://doi.org/10.5194/acp-12-12037-2012, 2012
Related subject area
Subject: Aerosols | Research Activity: Atmospheric Modelling and Data Analysis | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)
Dimethyl sulfide chemistry over the industrial era: comparison of key oxidation mechanisms and long-term observations
Driving factors of aerosol acidity: a new hierarchical quantitative analysis framework and its application in Changzhou, China
Understanding the long-term trend of organic aerosol and the influences from anthropogenic emission and regional climate change in China
Population exposure to outdoor NO2, black carbon, and ultrafine and fine particles over Paris with multi-scale modelling down to the street scale
Predicted impacts of heterogeneous chemical pathways on particulate sulfur over Fairbanks (Alaska), the Northern Hemisphere, and the Contiguous United States
Critical load exceedances for North America and Europe using an ensemble of models and an investigation of causes of environmental impact estimate variability: an AQMEII4 study
Impacts of meteorology and emission reductions on haze pollution during the lockdown in the North China Plain
Impact of mineral dust on the global nitrate aerosol direct and indirect radiative effect
The surface tension and cloud condensation nuclei (CCN) activation of sea spray aerosol particles
Exploring the processes controlling secondary inorganic aerosol: evaluating the global GEOS-Chem simulation using a suite of aircraft campaigns
Influence of land cover change on atmospheric organic gases, aerosols, and radiative effects
Quantifying the impacts of marine aerosols over the southeast Atlantic Ocean using a chemical transport model: implications for aerosol–cloud interactions
Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NOx
Rapid oxidation of phenolic compounds by O3 and HO●: effects of the air–water interface and mineral dust in tropospheric chemical processes
Uncertainties in the effects of organic aerosol coatings on polycyclic aromatic hydrocarbon concentrations and their estimated health effects
Modeling the contribution of leads to sea spray aerosol in the high Arctic
Trends and Drivers of Soluble Iron Deposition from East Asian Dust to the Northwest Pacific: A Springtime Analysis (2001–2017)
Impacts of Sea Ice Leads on Sea Salt Aerosols and Atmospheric Chemistry in the Arctic
Implications of Reduced-Complexity Aerosol Thermodynamics on Organic Aerosol Mass Concentration and Composition over North America
Importance of aerosol composition and aerosol vertical profiles in global spatial variation in the relationship between PM2.5 and aerosol optical depth
The co-benefits of a low-carbon future for PM2.5 and O3 air pollution in Europe
Assessing the effectiveness of SO2, NOx, and NH3 emission reductions in mitigating winter PM2.5 in Taiwan using CMAQ
Modelling of atmospheric concentrations of fungal spores: a 2-year simulation over France using CHIMERE
Cluster-dynamics-based parameterization for sulfuric acid–dimethylamine nucleation: comparison and selection through box and three-dimensional modeling
A Comprehensive Global Modelling Assessment of Nitrate Heterogeneous Formation on Desert Dust
Modelling of atmospheric variability of gas and aerosols during the ACROSS campaign 2022 in the greater Paris area: evaluation of the meteorology, dynamics and chemistry
Observed and CMIP6-model-simulated organic aerosol response to drought in the contiguous United States during summertime
Long-term trends in aerosol properties derived from AERONET measurements
Cooling radiative forcing effect enhancement of atmospheric amines and mineral particles caused by heterogeneous uptake and oxidation
Source-resolved atmospheric metal emissions, concentrations, and deposition fluxes into the East Asian seas
Analysis of secondary inorganic aerosols over the greater Athens area using the EPISODE–CityChem source dispersion and photochemistry model
Global estimates of ambient reactive nitrogen components during 2000–2100 based on the multi-stage model
The role of naphthalene and its derivatives in the formation of secondary organic aerosol in the Yangtze River Delta region, China
Unveiling the optimal regression model for source apportionment of the oxidative potential of PM10
AERO-MAP: A data compilation and modelling approach to understand spatial variability in fine and coarse mode aerosol composition
Investigating the contribution of grown new particles to cloud condensation nuclei with largely varying preexisting particles – Part 2: Modeling chemical drivers and 3-D new particle formation occurrence
Technical note: Influence of different averaging metrics and temporal resolutions on the aerosol pH calculated by thermodynamic modeling
Dual roles of the inorganic aqueous phase on secondary organic aerosol growth from benzene and phenol
Global source apportionment of aerosols into major emission regions and sectors over 1850–2017
Modeling atmospheric brown carbon in the GISS ModelE Earth system model
Observation-constrained kinetic modeling of isoprene SOA formation in the atmosphere
Significant impact of urban tree biogenic emissions on air quality estimated by a bottom-up inventory and chemistry transport modeling
Secondary organic aerosols derived from intermediate-volatility n-alkanes adopt low-viscous phase state
Spatial-temporal patterns of anthropogenic and biomass burning contributions on air pollution and mortality burden changes in India from 1995 to 2014
Modeling the drivers of fine PM pollution over Central Europe: impacts and contributions of emissions from different sources
Reaction of SO3 with H2SO4 and its implications for aerosol particle formation in the gas phase and at the air–water interface
Weakened aerosol–radiation interaction exacerbating ozone pollution in eastern China since China's clean air actions
Uncertainties from biomass burning aerosols in air quality models obscure public health impacts in Southeast Asia
Oxidative potential apportionment of atmospheric PM1: a new approach combining high-sensitive online analysers for chemical composition and offline OP measurement technique
Aqueous-phase chemistry of glyoxal with multifunctional reduced nitrogen compounds: a potential missing route for secondary brown carbon
Ursula A. Jongebloed, Jacob I. Chalif, Linia Tashmim, William C. Porter, Kelvin H. Bates, Qianjie Chen, Erich C. Osterberg, Bess G. Koffman, Jihong Cole-Dai, Dominic A. Winski, David G. Ferris, Karl J. Kreutz, Cameron P. Wake, and Becky Alexander
Atmos. Chem. Phys., 25, 4083–4106, https://doi.org/10.5194/acp-25-4083-2025, https://doi.org/10.5194/acp-25-4083-2025, 2025
Short summary
Short summary
Marine phytoplankton emit dimethyl sulfide (DMS), which forms methanesulfonic acid (MSA) and sulfate. MSA concentrations in ice cores decreased over the industrial era, which has been attributed to pollution-driven changes in DMS chemistry. We use a model to investigate DMS chemistry compared to observations of DMS, MSA, and sulfate. We find that modeled DMS, MSA, and sulfate are influenced by pollution-sensitive oxidant concentrations, characterization of DMS chemistry, and other variables.
Xiaolin Duan, Guangjie Zheng, Chuchu Chen, Qiang Zhang, and Kebin He
Atmos. Chem. Phys., 25, 3919–3928, https://doi.org/10.5194/acp-25-3919-2025, https://doi.org/10.5194/acp-25-3919-2025, 2025
Short summary
Short summary
Aerosol acidity is an important parameter in atmospheric chemistry, while its driving factors, especially chemical profiles versus meteorological conditions, are not yet fully understood. Here, we established a hierarchical quantitative analysis framework to understand the driving factors of aerosol acidity on different timescales. Its application in Changzhou, China, revealed distinct driving factors and corresponding mechanisms of aerosol acidity from annual trends to random residuals.
Wenxin Zhang, Yaman Liu, Man Yue, Xinyi Dong, Kan Huang, and Minghuai Wang
Atmos. Chem. Phys., 25, 3857–3872, https://doi.org/10.5194/acp-25-3857-2025, https://doi.org/10.5194/acp-25-3857-2025, 2025
Short summary
Short summary
Understanding long-term organic aerosol (OA) trends and their driving factors is important for air quality management. Our modeling revealed that OA in China increased by 5.6 % from 1990 to 2019, primarily due to a 32.3 % increase in secondary organic aerosols (SOAs) and an 8.1 % decrease in primary organic aerosols (POAs), both largely driven by changes in anthropogenic emissions. Biogenic SOA increased due to warming but showed little response to changes in anthropogenic nitrogen oxide emissions.
Soo-Jin Park, Lya Lugon, Oscar Jacquot, Youngseob Kim, Alexia Baudic, Barbara D'Anna, Ludovico Di Antonio, Claudia Di Biagio, Fabrice Dugay, Olivier Favez, Véronique Ghersi, Aline Gratien, Julien Kammer, Jean-Eudes Petit, Olivier Sanchez, Myrto Valari, Jérémy Vigneron, and Karine Sartelet
Atmos. Chem. Phys., 25, 3363–3387, https://doi.org/10.5194/acp-25-3363-2025, https://doi.org/10.5194/acp-25-3363-2025, 2025
Short summary
Short summary
To accurately represent the population exposure to outdoor concentrations of pollutants of interest to health (NO2, PM2.5, black carbon, and ultrafine particles), multi-scale modelling down to the street scale is set up and evaluated using measurements from field campaigns. An exposure scaling factor is defined, allowing regional-scale simulations to be corrected to evaluate population exposure. Urban heterogeneities strongly influence NO2, black carbon, and ultrafine particles but less strongly PM2.5.
Sara L. Farrell, Havala O. T. Pye, Robert Gilliam, George Pouliot, Deanna Huff, Golam Sarwar, William Vizuete, Nicole Briggs, Fengkui Duan, Tao Ma, Shuping Zhang, and Kathleen Fahey
Atmos. Chem. Phys., 25, 3287–3312, https://doi.org/10.5194/acp-25-3287-2025, https://doi.org/10.5194/acp-25-3287-2025, 2025
Short summary
Short summary
In this work we implement heterogeneous sulfur chemistry into the Community Multiscale Air Quality (CMAQ) model. This new chemistry accounts for the formation of sulfate via aqueous oxidation of SO2 in aerosol liquid water and the formation of hydroxymethanesulfonate (HMS) – often confused by measurement techniques as sulfate. Model performance in predicting sulfur PM2.5 in Fairbanks, Alaska, and other places that experience dark and cold winters is improved.
Paul A. Makar, Philip Cheung, Christian Hogrefe, Ayodeji Akingunola, Ummugulsum Alyuz, Jesse O. Bash, Michael D. Bell, Roberto Bellasio, Roberto Bianconi, Tim Butler, Hazel Cathcart, Olivia E. Clifton, Alma Hodzic, Ioannis Kioutsioukis, Richard Kranenburg, Aurelia Lupascu, Jason A. Lynch, Kester Momoh, Juan L. Perez-Camanyo, Jonathan Pleim, Young-Hee Ryu, Roberto San Jose, Donna Schwede, Thomas Scheuschner, Mark W. Shephard, Ranjeet S. Sokhi, and Stefano Galmarini
Atmos. Chem. Phys., 25, 3049–3107, https://doi.org/10.5194/acp-25-3049-2025, https://doi.org/10.5194/acp-25-3049-2025, 2025
Short summary
Short summary
The large range of sulfur and nitrogen deposition estimates from air quality models results in a large range of predicted impacts. We used models and deposition diagnostics to identify the processes controlling atmospheric sulfur and nitrogen deposition variability. Controlling factors included the uptake of gases and aerosols by hydrometeors, aerosol inorganic chemistry, particle dry deposition, ammonia bidirectional fluxes, gas deposition via plant cuticles and soil, and land use data.
Lang Liu, Xin Long, Yi Li, Zengliang Zang, Fengwen Wang, Yan Han, Zhier Bao, Yang Chen, Tian Feng, and Jinxin Yang
Atmos. Chem. Phys., 25, 1569–1585, https://doi.org/10.5194/acp-25-1569-2025, https://doi.org/10.5194/acp-25-1569-2025, 2025
Short summary
Short summary
This study uses WRF-Chem to assess how meteorological conditions and emission reductions affected fine particulate matter (PM2.5) in the North China Plain (NCP). It highlights regional disparities: in the northern NCP, adverse weather negated emission reduction effects. In contrast, the southern NCP featured a PM2.5 decrease due to favorable weather and emission reductions. The research highlighted the interaction between emissions, meteorology, and PM2.5.
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
Short summary
Short summary
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.
Judith Kleinheins, Nadia Shardt, Ulrike Lohmann, and Claudia Marcolli
Atmos. Chem. Phys., 25, 881–903, https://doi.org/10.5194/acp-25-881-2025, https://doi.org/10.5194/acp-25-881-2025, 2025
Short summary
Short summary
We model the cloud condensation nuclei (CCN) activation of sea spray aerosol particles with classical Köhler theory and with a new model approach that takes surface tension lowering into account. We categorize organic compounds into weak, intermediate, and strong surfactants, and we outline for which composition surface tension lowering is important. The results suggest that surface tension lowering allows sea spray aerosol particles in the Aitken mode to be a source of CCN in marine updraughts.
Olivia G. Norman, Colette L. Heald, Solomon Bililign, Pedro Campuzano-Jost, Hugh Coe, Marc N. Fiddler, Jaime R. Green, Jose L. Jimenez, Katharina Kaiser, Jin Liao, Ann M. Middlebrook, Benjamin A. Nault, John B. Nowak, Johannes Schneider, and André Welti
Atmos. Chem. Phys., 25, 771–795, https://doi.org/10.5194/acp-25-771-2025, https://doi.org/10.5194/acp-25-771-2025, 2025
Short summary
Short summary
This study finds that one component of secondary inorganic aerosols, nitrate, is greatly overestimated by a global atmospheric chemistry model compared to observations from 11 flight campaigns. None of the loss and production pathways explored can explain the nitrate bias alone. The model’s inability to capture the variability in the observations remains and requires future investigation to avoid biases in policy-related studies (i.e., air quality, health, climate impacts of these aerosols).
Ryan Vella, Matthew Forrest, Andrea Pozzer, Alexandra P. Tsimpidi, Thomas Hickler, Jos Lelieveld, and Holger Tost
Atmos. Chem. Phys., 25, 243–262, https://doi.org/10.5194/acp-25-243-2025, https://doi.org/10.5194/acp-25-243-2025, 2025
Short summary
Short summary
This study examines how land cover changes influence biogenic volatile organic compound (BVOC) emissions and atmospheric states. Using a coupled chemistry–climate–vegetation model, we compare present-day land cover (deforested for crops and grazing) with natural vegetation and an extreme reforestation scenario. We find that vegetation changes significantly impact global BVOC emissions and organic aerosols but have a relatively small effect on total aerosols, clouds, and radiative effects.
Mashiat Hossain, Rebecca M. Garland, and Hannah M. Horowitz
Atmos. Chem. Phys., 24, 14123–14143, https://doi.org/10.5194/acp-24-14123-2024, https://doi.org/10.5194/acp-24-14123-2024, 2024
Short summary
Short summary
Our research examines aerosol dynamics over the southeast Atlantic, a region with significant uncertainties in aerosol radiative forcings. Using the GEOS-Chem model, we find that at cloud altitudes, organic aerosols dominate during the biomass burning season, while sulfate aerosols, driven by marine emissions, prevail during peak primary production. These findings highlight the need for accurate representation of marine aerosols in models to improve climate predictions and reduce uncertainties.
Ashok K. Luhar, Anthony C. Jones, and Jonathan M. Wilkinson
Atmos. Chem. Phys., 24, 14005–14028, https://doi.org/10.5194/acp-24-14005-2024, https://doi.org/10.5194/acp-24-14005-2024, 2024
Short summary
Short summary
Nitrate aerosol is often omitted in global chemistry–climate models, partly due to the chemical complexity of its formation process. Using a global model, we show that including nitrate aerosol significantly impacts tropospheric composition fields, such as ozone, and radiation. Additionally, lightning-generated oxides of nitrogen influence both nitrate aerosol mass concentrations and aerosol size distribution, which has important implications for radiative fluxes and indirect aerosol effects.
Yanru Huo, Mingxue Li, Xueyu Wang, Jianfei Sun, Yuxin Zhou, Yuhui Ma, and Maoxia He
Atmos. Chem. Phys., 24, 12409–12423, https://doi.org/10.5194/acp-24-12409-2024, https://doi.org/10.5194/acp-24-12409-2024, 2024
Short summary
Short summary
This work found that the air–water (A–W) interface and TiO2 clusters promote the oxidation of phenolic compounds (PhCs) to varying degrees compared with the gas phase and bulk water. Some byproducts are more harmful than their parent compounds. This work provides important evidence for the rapid oxidation observed in O3/HO• + PhC experiments at the A–W interface and in mineral dust.
Sijia Lou, Manish Shrivastava, Alexandre Albinet, Sophie Tomaz, Deepchandra Srivastava, Olivier Favez, Huizhong Shen, and Aijun Ding
EGUsphere, https://doi.org/10.5194/egusphere-2024-3269, https://doi.org/10.5194/egusphere-2024-3269, 2024
Short summary
Short summary
PAHs, emitted from incomplete combustion, pose serious health risks due to their carcinogenic properties. This research demonstrates that viscous organic aerosol coatings significantly hinder PAH oxidation, with spatial distributions sensitive to the degradation modelling approach. Our findings underscore the importance of accurately modelling these processes for risk assessments, highlighting the need to consider both fresh and oxidized PAHs in evaluating human exposure and health risks.
Rémy Lapere, Louis Marelle, Pierre Rampal, Laurent Brodeau, Christian Melsheimer, Gunnar Spreen, and Jennie L. Thomas
Atmos. Chem. Phys., 24, 12107–12132, https://doi.org/10.5194/acp-24-12107-2024, https://doi.org/10.5194/acp-24-12107-2024, 2024
Short summary
Short summary
Elongated open-water areas in sea ice, called leads, can release marine aerosols into the atmosphere. In the Arctic, this source of atmospheric particles could play an important role for climate. However, the amount, seasonality and spatial distribution of such emissions are all mostly unknown. Here, we propose a first parameterization for sea spray aerosols emitted through leads in sea ice and quantify their impact on aerosol populations in the high Arctic.
Hanzheng Zhu, Yaman Liu, Man Yue, Shihui Feng, Pingqing Fu, Kan Huang, Xinyi Dong, and Minghuai Wang
EGUsphere, https://doi.org/10.5194/egusphere-2024-2293, https://doi.org/10.5194/egusphere-2024-2293, 2024
Short summary
Short summary
Dust soluble iron deposition from East Asia plays an important role in the marine ecology of the Northwest Pacific. Using the developed model, our findings highlight a dual trend: a decrease in the overall deposition of soluble iron from dust, but an increase in the solubility of the iron itself due to the enhanced atmospheric processing. It underscores the critical roles of both dust emission and atmospheric processing in soluble iron deposition and marine ecology.
Erin Emme and Hannah Horowitz
EGUsphere, https://doi.org/10.5194/egusphere-2024-3147, https://doi.org/10.5194/egusphere-2024-3147, 2024
Short summary
Short summary
There is uncertainty in the sources of Arctic cold season (November-April) sea salt aerosols. Using a chemical transport model and satellite observations, we quantify Arctic-wide sea salt aerosol emissions from fractures in sea ice, called open sea ice leads, and their atmospheric chemistry impacts for the cold season. We show sea ice leads contribute to Arctic sea salt aerosols and bromine, especially in under-observed regions.
Camilo Serrano Damha, Kyle Gorkowski, and Andreas Zuend
EGUsphere, https://doi.org/10.5194/egusphere-2024-2712, https://doi.org/10.5194/egusphere-2024-2712, 2024
Short summary
Short summary
Organic aerosol water content impacts the gas–particle partitioning of semivolatile organics. We used an aerosol thermodynamic model in the GEOS-Chem chemical transport model to efficiently account for organic aerosol water uptake and nonideal mixing. This led to a substantial enhancement in mean organic aerosol mass concentration with respect to GEOS-Chem's most advanced scheme. The water-sensitive scheme could be a valuable tool for reconciling model estimations and field measurements.
Haihui Zhu, Randall V. Martin, Aaron van Donkelaar, Melanie S. Hammer, Chi Li, Jun Meng, Christopher R. Oxford, Xuan Liu, Yanshun Li, Dandan Zhang, Inderjeet Singh, and Alexei Lyapustin
Atmos. Chem. Phys., 24, 11565–11584, https://doi.org/10.5194/acp-24-11565-2024, https://doi.org/10.5194/acp-24-11565-2024, 2024
Short summary
Short summary
Ambient fine particulate matter (PM2.5) contributes to 4 million deaths globally each year. Satellite remote sensing of aerosol optical depth (AOD), coupled with a simulated PM2.5–AOD relationship (η), can provide global PM2.5 estimations. This study aims to understand the spatial patterns and driving factors of η to guide future measurement and modeling efforts. We quantified η globally and regionally and found that its spatial variation is strongly influenced by aerosol composition.
Connor J. Clayton, Daniel R. Marsh, Steven T. Turnock, Ailish M. Graham, Kirsty J. Pringle, Carly L. Reddington, Rajesh Kumar, and James B. McQuaid
Atmos. Chem. Phys., 24, 10717–10740, https://doi.org/10.5194/acp-24-10717-2024, https://doi.org/10.5194/acp-24-10717-2024, 2024
Short summary
Short summary
We demonstrate that strong climate mitigation could improve air quality in Europe; however, less ambitious mitigation does not result in these co-benefits. We use a high-resolution atmospheric chemistry model. This allows us to demonstrate how this varies across European countries and analyse the underlying chemistry. This may help policy-facing researchers understand which sectors and regions need to be prioritised to achieve strong air quality co-benefits of climate mitigation.
Ping-Chieh Huang, Hui-Ming Hung, Hsin-Chih Lai, and Charles C.-K. Chou
Atmos. Chem. Phys., 24, 10759–10772, https://doi.org/10.5194/acp-24-10759-2024, https://doi.org/10.5194/acp-24-10759-2024, 2024
Short summary
Short summary
Models were used to study ways to reduce particulate matter (PM) pollution in Taiwan during winter. After considering various factors, such as physical processes and chemical reactions, we found that reducing NOx or NH3 emissions is more effective at mitigating PM2.5 than reducing SO2 emissions. When considering both efficiency and cost, reducing NH3 emissions seems to be a more suitable policy for the studied environment in Taiwan.
Matthieu Vida, Gilles Foret, Guillaume Siour, Florian Couvidat, Olivier Favez, Gaelle Uzu, Arineh Cholakian, Sébastien Conil, Matthias Beekmann, and Jean-Luc Jaffrezo
Atmos. Chem. Phys., 24, 10601–10615, https://doi.org/10.5194/acp-24-10601-2024, https://doi.org/10.5194/acp-24-10601-2024, 2024
Short summary
Short summary
We simulate 2 years of atmospheric fungal spores over France and use observations of polyols and primary biogenic factors from positive matrix factorisation. The representation of emissions taking into account a proxy for vegetation surface and specific humidity enables us to reproduce very accurately the seasonal cycle of fungal spores. Furthermore, we estimate that fungal spores can account for 20 % of PM10 and 40 % of the organic fraction of PM10 over vegetated areas in summer.
Jiewen Shen, Bin Zhao, Shuxiao Wang, An Ning, Yuyang Li, Runlong Cai, Da Gao, Biwu Chu, Yang Gao, Manish Shrivastava, Jingkun Jiang, Xiuhui Zhang, and Hong He
Atmos. Chem. Phys., 24, 10261–10278, https://doi.org/10.5194/acp-24-10261-2024, https://doi.org/10.5194/acp-24-10261-2024, 2024
Short summary
Short summary
We extensively compare various cluster-dynamics-based parameterizations for sulfuric acid–dimethylamine nucleation and identify a newly developed parameterization derived from Atmospheric Cluster Dynamic Code (ACDC) simulations as being the most reliable one. This study offers a valuable reference for developing parameterizations of other nucleation systems and is meaningful for the accurate quantification of the environmental and climate impacts of new particle formation.
Rubén Soussé-Villa, Oriol Jorba, María Gonçalves Ageitos, Dene Bowdalo, Marc Guevara, and Carlos Pérez García-Pando
EGUsphere, https://doi.org/10.5194/egusphere-2024-2310, https://doi.org/10.5194/egusphere-2024-2310, 2024
Short summary
Short summary
Desert dust forms nitrate coatings as it travels through the atmosphere. However, current models that predict this process vary greatly due to different methods and inaccuracies. We examined how nitrate forms in a global model, focusing on how gases condense on dust, the lifespan of different particles, and the impact of alkalinity. Our findings show that models work best when they consider reversible gas condensation with alkalinity. This should lead to better estimates of climate impacts.
Ludovico Di Antonio, Matthias Beekmann, Guillaume Siour, Vincent Michoud, Christopher Cantrell, Astrid Bauville, Antonin Bergé, Mathieu Cazaunau, Servanne Chevaillier, Manuela Cirtog, Joel F. de Brito, Paola Formenti, Cecile Gaimoz, Olivier Garret, Aline Gratien, Valérie Gros, Martial Haeffelin, Lelia N. Hawkins, Simone Kotthaus, Gael Noyalet, Diana Pereira, Jean-Eudes Petit, Eva Drew Pronovost, Véronique Riffault, Chenjie Yu, Gilles Foret, Jean-François Doussin, and Claudia Di Biagio
EGUsphere, https://doi.org/10.5194/egusphere-2024-2175, https://doi.org/10.5194/egusphere-2024-2175, 2024
Short summary
Short summary
Summer 2022 has been considered a proxy for future climate scenarios, given the registered hot and dry conditions. In this paper, we used the measurements from the ACROSS campaign, occurred over the Paris area in June–July 2022, in addition to observations from existing networks, to evaluate the WRF–CHIMERE model simulation over France and the Ile-de-France regions. Results over the Ile–de–France show to be satisfactory, allowing to explain the gas and aerosol variability at the ACROSS sites.
Wei Li and Yuxuan Wang
Atmos. Chem. Phys., 24, 9339–9353, https://doi.org/10.5194/acp-24-9339-2024, https://doi.org/10.5194/acp-24-9339-2024, 2024
Short summary
Short summary
Droughts immensely increased organic aerosol (OA) in the contiguous United States in summer (1998–2019), notably in the Pacific Northwest (PNW) and Southeast (SEUS). The OA rise in the SEUS is driven by the enhanced formation of epoxydiol-derived secondary organic aerosol due to the increase in biogenic volatile organic compounds and sulfate, while in the PNW, it is caused by wildfires. A total of 10 climate models captured the OA increase in the PNW yet greatly underestimated it in the SEUS.
Zhenyu Zhang, Jing Li, Huizheng Che, Yueming Dong, Oleg Dubovik, Thomas Eck, Pawan Gupta, Brent Holben, Jhoon Kim, Elena Lind, Trailokya Saud, Sachchida Nand Tripathi, and Tong Ying
EGUsphere, https://doi.org/10.5194/egusphere-2024-2533, https://doi.org/10.5194/egusphere-2024-2533, 2024
Short summary
Short summary
We used ground-based remote sensing data from the Aerosol Robotic Network to examine long-term trends in aerosol characteristics. We found aerosol loadings generally decreased globally, and aerosols became more scattering. These changes are closely related to variations in aerosol compositions, such as decreased anthropogenic emissions over East Asia, Europe, and North America, increased anthropogenic source over North India, increased dust activities over the Arabian Peninsula, etc.
Weina Zhang, Jianhua Mai, Zhichao Fan, Yongpeng Ji, Yuemeng Ji, Guiying Li, Yanpeng Gao, and Taicheng An
Atmos. Chem. Phys., 24, 9019–9030, https://doi.org/10.5194/acp-24-9019-2024, https://doi.org/10.5194/acp-24-9019-2024, 2024
Short summary
Short summary
This study reveals heterogeneous oxidation causes further radiative forcing effect (RFE) enhancement of amine–mineral mixed particles. Note that RFE increment is higher under clean conditions than that under polluted conditions, which is contributed to high-oxygen-content products. The enhanced RFE of amine–mineral particles caused by heterogenous oxidation is expected to alleviate warming effects.
Shenglan Jiang, Yan Zhang, Guangyuan Yu, Zimin Han, Junri Zhao, Tianle Zhang, and Mei Zheng
Atmos. Chem. Phys., 24, 8363–8381, https://doi.org/10.5194/acp-24-8363-2024, https://doi.org/10.5194/acp-24-8363-2024, 2024
Short summary
Short summary
This study aims to provide gridded data on sea-wide concentrations, deposition fluxes, and soluble deposition fluxes with detailed source categories of metals using the modified CMAQ model. We developed a monthly emission inventory of six metals – Fe, Al, V, Ni, Zn, and Cu – from terrestrial anthropogenic, ship, and dust sources in East Asia in 2017. Our results reveal the contribution of each source to the emissions, concentrations, and deposition fluxes of metals in the East Asian seas.
Stelios Myriokefalitakis, Matthias Karl, Kim A. Weiss, Dimitris Karagiannis, Eleni Athanasopoulou, Anastasia Kakouri, Aikaterini Bougiatioti, Eleni Liakakou, Iasonas Stavroulas, Georgios Papangelis, Georgios Grivas, Despina Paraskevopoulou, Orestis Speyer, Nikolaos Mihalopoulos, and Evangelos Gerasopoulos
Atmos. Chem. Phys., 24, 7815–7835, https://doi.org/10.5194/acp-24-7815-2024, https://doi.org/10.5194/acp-24-7815-2024, 2024
Short summary
Short summary
A state-of-the-art thermodynamic model has been coupled with the city-scale chemistry transport model EPISODE–CityChem to investigate the equilibrium between the inorganic gas and aerosol phases over the greater Athens area, Greece. The simulations indicate that the formation of nitrates in an urban environment is significantly affected by local nitrogen oxide emissions, as well as ambient temperature, relative humidity, photochemical activity, and the presence of non-volatile cations.
Rui Li, Yining Gao, Lijia Zhang, Yubing Shen, Tianzhao Xu, Wenwen Sun, and Gehui Wang
Atmos. Chem. Phys., 24, 7623–7636, https://doi.org/10.5194/acp-24-7623-2024, https://doi.org/10.5194/acp-24-7623-2024, 2024
Short summary
Short summary
A three-stage model was developed to obtain the global maps of reactive nitrogen components during 2000–2100. The results implied that cross-validation R2 values of four species showed satisfactory performance (R2 > 0.55). Most reactive nitrogen components, except NH3, in China showed increases during 2000–2013. In the future scenarios, SSP3-7.0 (traditional-energy scenario) and SSP1-2.6 (carbon neutrality scenario) showed the highest and lowest reactive nitrogen component concentrations.
Fei Ye, Jingyi Li, Yaqin Gao, Hongli Wang, Jingyu An, Cheng Huang, Song Guo, Keding Lu, Kangjia Gong, Haowen Zhang, Momei Qin, and Jianlin Hu
Atmos. Chem. Phys., 24, 7467–7479, https://doi.org/10.5194/acp-24-7467-2024, https://doi.org/10.5194/acp-24-7467-2024, 2024
Short summary
Short summary
Naphthalene (Nap) and methylnaphthalene (MN) are key precursors of secondary organic aerosol (SOA), yet their sources and sinks are often inadequately represented in air quality models. In this study, we incorporated detailed emissions, gas-phase chemistry, and SOA parameterization of Nap and MN into CMAQ to address this issue. The findings revealed remarkably high SOA formation potentials for these compounds despite their low emissions in the Yangtze River Delta region during summer.
Vy Dinh Ngoc Thuy, Jean-Luc Jaffrezo, Ian Hough, Pamela A. Dominutti, Guillaume Salque Moreton, Grégory Gille, Florie Francony, Arabelle Patron-Anquez, Olivier Favez, and Gaëlle Uzu
Atmos. Chem. Phys., 24, 7261–7282, https://doi.org/10.5194/acp-24-7261-2024, https://doi.org/10.5194/acp-24-7261-2024, 2024
Short summary
Short summary
The capacity of particulate matter (PM) to generate reactive oxygen species in vivo is represented by oxidative potential (OP). This study focuses on finding the appropriate model to evaluate the oxidative character of PM sources in six sites using the PM sources and OP. Eight regression techniques are introduced to assess the OP of PM. The study highlights the importance of selecting a model according to the input data characteristics and establishes some recommendations for the procedure.
Natalie M. Mahowald, Longlei Li, Julius Vira, Marje Prank, Douglas S. Hamilton, Hitoshi Matsui, Ron L. Miller, Louis Lu, Ezgi Akyuz, Daphne Meidan, Peter G. Hess, Heikki Lihavainen, Christine Wiedinmyer, Jenny Hand, Maria Grazia Alaimo, Célia Alves, Andres Alastuey, Paulo Artaxo, Africa Barreto, Francisco Barraza, Silvia Becagli, Giulia Calzolai, Shankararaman Chellam, Ying Chen, Patrick Chuang, David D. Cohen, Cristina Colombi, Evangelia Diapouli, Gaetano Dongarra, Konstantinos Eleftheriadis, Johann Engelbrecht, Corinne Galy-Lacaux, Cassandra Gaston, Dario Gomez, Yenny González Ramos, Roy M. Harrison, Chris Heyes, Barak Herut, Philip Hopke, Christoph Hüglin, Maria Kanakidou, Zsofia Kertesz, Zbigniew Klimont, Katriina Kyllönen, Fabrice Lambert, Xiaohong Liu, Remi Losno, Franco Lucarelli, Willy Maenhaut, Beatrice Marticorena, Randall V. Martin, Nikolaos Mihalopoulos, Yasser Morera-Gomez, Adina Paytan, Joseph Prospero, Sergio Rodríguez, Patricia Smichowski, Daniela Varrica, Brenna Walsh, Crystal Weagle, and Xi Zhao
EGUsphere, https://doi.org/10.5194/egusphere-2024-1617, https://doi.org/10.5194/egusphere-2024-1617, 2024
Short summary
Short summary
Aerosol particles are an important part of the Earth system, but their concentrations are spatially and temporally heterogeneous, as well as variable in size and composition. Here we present a new compilation of PM2.5 and PM10 aerosol observations, focusing on the spatial variability across different observational stations, including composition, and demonstrate a method for comparing the datasets to model output.
Ming Chu, Xing Wei, Shangfei Hai, Yang Gao, Huiwang Gao, Yujiao Zhu, Biwu Chu, Nan Ma, Juan Hong, Yele Sun, and Xiaohong Yao
Atmos. Chem. Phys., 24, 6769–6786, https://doi.org/10.5194/acp-24-6769-2024, https://doi.org/10.5194/acp-24-6769-2024, 2024
Short summary
Short summary
We used a 20-bin WRF-Chem model to simulate NPF events in the NCP during a three-week observational period in the summer of 2019. The model was able to reproduce the observations during June 29–July 6, which was characterized by a high frequency of NPF occurrence.
Haoqi Wang, Xiao Tian, Wanting Zhao, Jiacheng Li, Haoyu Yu, Yinchang Feng, and Shaojie Song
Atmos. Chem. Phys., 24, 6583–6592, https://doi.org/10.5194/acp-24-6583-2024, https://doi.org/10.5194/acp-24-6583-2024, 2024
Short summary
Short summary
pH is a key property of ambient aerosols, which affect many atmospheric processes. As aerosol pH is a non-conservative parameter, diverse averaging metrics and temporal resolutions may influence the pH values calculated by thermodynamic models. This technical note seeks to quantitatively evaluate the average pH using varied metrics and resolutions. The ultimate goal is to establish standardized reporting practices in future research endeavors.
Jiwon Choi, Myoseon Jang, and Spencer Blau
Atmos. Chem. Phys., 24, 6567–6582, https://doi.org/10.5194/acp-24-6567-2024, https://doi.org/10.5194/acp-24-6567-2024, 2024
Short summary
Short summary
Persistent phenoxy radical (PPR), formed by phenol gas oxidation and its aqueous reaction, catalytically destroys O3 and retards secondary organic aerosol (SOA) growth. Explicit gas mechanisms including the formation of PPR and low-volatility products from the oxidation of phenol or benzene are applied to the UNIPAR model to predict SOA mass via multiphase reactions of precursors. Aqueous reactions of reactive organics increase SOA mass but retard SOA growth via heterogeneously formed PPR.
Yang Yang, Shaoxuan Mou, Hailong Wang, Pinya Wang, Baojie Li, and Hong Liao
Atmos. Chem. Phys., 24, 6509–6523, https://doi.org/10.5194/acp-24-6509-2024, https://doi.org/10.5194/acp-24-6509-2024, 2024
Short summary
Short summary
The variations in anthropogenic aerosol concentrations and source contributions and their subsequent radiative impact in major emission regions during historical periods are quantified based on an aerosol-tagging system in E3SMv1. Due to the industrial development and implementation of economic policies, sources of anthropogenic aerosols show different variations, which has important implications for pollution prevention and control measures and decision-making for global collaboration.
Maegan A. DeLessio, Kostas Tsigaridis, Susanne E. Bauer, Jacek Chowdhary, and Gregory L. Schuster
Atmos. Chem. Phys., 24, 6275–6304, https://doi.org/10.5194/acp-24-6275-2024, https://doi.org/10.5194/acp-24-6275-2024, 2024
Short summary
Short summary
This study presents the first explicit representation of brown carbon aerosols in the GISS ModelE Earth system model (ESM). Model sensitivity to a range of brown carbon parameters and model performance compared to AERONET and MODIS retrievals of total aerosol properties were assessed. A summary of best practices for incorporating brown carbon into ModelE is also included.
Chuanyang Shen, Xiaoyan Yang, Joel Thornton, John Shilling, Chenyang Bi, Gabriel Isaacman-VanWertz, and Haofei Zhang
Atmos. Chem. Phys., 24, 6153–6175, https://doi.org/10.5194/acp-24-6153-2024, https://doi.org/10.5194/acp-24-6153-2024, 2024
Short summary
Short summary
In this work, a condensed multiphase isoprene oxidation mechanism was developed to simulate isoprene SOA formation from chamber and field studies. Our results show that the measured isoprene SOA mass concentrations can be reasonably reproduced. The simulation results indicate that multifunctional low-volatility products contribute significantly to total isoprene SOA. Our findings emphasize that the pathways to produce these low-volatility species should be considered in models.
Alice Maison, Lya Lugon, Soo-Jin Park, Alexia Baudic, Christopher Cantrell, Florian Couvidat, Barbara D'Anna, Claudia Di Biagio, Aline Gratien, Valérie Gros, Carmen Kalalian, Julien Kammer, Vincent Michoud, Jean-Eudes Petit, Marwa Shahin, Leila Simon, Myrto Valari, Jérémy Vigneron, Andrée Tuzet, and Karine Sartelet
Atmos. Chem. Phys., 24, 6011–6046, https://doi.org/10.5194/acp-24-6011-2024, https://doi.org/10.5194/acp-24-6011-2024, 2024
Short summary
Short summary
This study presents the development of a bottom-up inventory of urban tree biogenic emissions. Emissions are computed for each tree based on their location and characteristics and are integrated in the regional air quality model WRF-CHIMERE. The impact of these biogenic emissions on air quality is quantified for June–July 2022. Over Paris city, urban trees increase the concentrations of particulate organic matter by 4.6 %, of PM2.5 by 0.6 %, and of ozone by 1.0 % on average over 2 months.
Tommaso Galeazzo, Bernard Aumont, Marie Camredon, Richard Valorso, Yong B. Lim, Paul J. Ziemann, and Manabu Shiraiwa
Atmos. Chem. Phys., 24, 5549–5565, https://doi.org/10.5194/acp-24-5549-2024, https://doi.org/10.5194/acp-24-5549-2024, 2024
Short summary
Short summary
Secondary organic aerosol (SOA) derived from n-alkanes is a major component of anthropogenic particulate matter. We provide an analysis of n-alkane SOA by chemistry modeling, machine learning, and laboratory experiments, showing that n-alkane SOA adopts low-viscous semi-solid or liquid states. Our results indicate few kinetic limitations of mass accommodation in SOA formation, supporting the application of equilibrium partitioning for simulating n-alkane SOA in large-scale atmospheric models.
Bin Luo, Yuqiang Zhang, Tao Tang, Hongliang Zhang, Jianlin Hu, Jiangshan Mu, Wenxing Wang, and Likun Xue
EGUsphere, https://doi.org/10.5194/egusphere-2024-974, https://doi.org/10.5194/egusphere-2024-974, 2024
Short summary
Short summary
India is facing a severe air pollution crisis that poses significant health risks, particularly from PM2.5 and O3. Our study reveals rising levels of both pollutants from 1995 to 2014, leading to increased premature mortality. While anthropogenic emissions play a significant role, biomass burning also impacts air quality, in particular seasons and regions in India. This study highlights the urgent need for localized policies to protect public health amid escalating environmental challenges.
Lukáš Bartík, Peter Huszár, Jan Karlický, Ondřej Vlček, and Kryštof Eben
Atmos. Chem. Phys., 24, 4347–4387, https://doi.org/10.5194/acp-24-4347-2024, https://doi.org/10.5194/acp-24-4347-2024, 2024
Short summary
Short summary
The presented study deals with the attribution of fine particulate matter (PM2.5) concentrations to anthropogenic emissions over Central Europe using regional-scale models. It calculates the present-day contributions of different emissions sectors to concentrations of PM2.5 and its secondary components. Moreover, the study investigates the effect of chemical nonlinearities by using multiple source attribution methods and secondary organic aerosol calculation methods.
Rui Wang, Yang Cheng, Shasha Chen, Rongrong Li, Yue Hu, Xiaokai Guo, Tianlei Zhang, Fengmin Song, and Hao Li
Atmos. Chem. Phys., 24, 4029–4046, https://doi.org/10.5194/acp-24-4029-2024, https://doi.org/10.5194/acp-24-4029-2024, 2024
Short summary
Short summary
We used quantum chemical calculations, Born–Oppenheimer molecular dynamics simulations, and the ACDC kinetic model to characterize SO3–H2SO4 interaction in the gas phase and at the air–water interface and to study the effect of H2S2O7 on H2SO4–NH3-based clusters. The work expands our understanding of new pathways for the loss of SO3 in acidic polluted areas and helps reveal some missing sources of NPF in metropolitan industrial regions and understand the atmospheric organic–sulfur cycle better.
Hao Yang, Lei Chen, Hong Liao, Jia Zhu, Wenjie Wang, and Xin Li
Atmos. Chem. Phys., 24, 4001–4015, https://doi.org/10.5194/acp-24-4001-2024, https://doi.org/10.5194/acp-24-4001-2024, 2024
Short summary
Short summary
The present study quantifies the response of aerosol–radiation interaction (ARI) to anthropogenic emission reduction from 2013 to 2017, with the main focus on the contribution to changed O3 concentrations over eastern China both in summer and winter using the WRF-Chem model. The weakened ARI due to decreased anthropogenic emission aggravates the summer (winter) O3 pollution by +0.81 ppb (+0.63 ppb), averaged over eastern China.
Margaret R. Marvin, Paul I. Palmer, Fei Yao, Mohd Talib Latif, and Md Firoz Khan
Atmos. Chem. Phys., 24, 3699–3715, https://doi.org/10.5194/acp-24-3699-2024, https://doi.org/10.5194/acp-24-3699-2024, 2024
Short summary
Short summary
We use an atmospheric chemistry model to investigate aerosols emitted from fire activity across Southeast Asia. We find that the limited nature of measurements in this region leads to large uncertainties that significantly hinder the model representation of these aerosols and their impacts on air quality. As a result, the number of monthly attributable deaths is underestimated by as many as 4500, particularly in March at the peak of the mainland burning season.
Julie Camman, Benjamin Chazeau, Nicolas Marchand, Amandine Durand, Grégory Gille, Ludovic Lanzi, Jean-Luc Jaffrezo, Henri Wortham, and Gaëlle Uzu
Atmos. Chem. Phys., 24, 3257–3278, https://doi.org/10.5194/acp-24-3257-2024, https://doi.org/10.5194/acp-24-3257-2024, 2024
Short summary
Short summary
Fine particle (PM1) pollution is a major health issue in the city of Marseille, which is subject to numerous pollution sources. Sampling carried out during the summer enabled a fine characterization of the PM1 sources and their oxidative potential, a promising new metric as a proxy for health impact. PM1 came mainly from combustion sources, secondary ammonium sulfate, and organic nitrate, while the oxidative potential of PM1 came from these sources and from resuspended dust in the atmosphere.
Yuemeng Ji, Zhang Shi, Wenjian Li, Jiaxin Wang, Qiuju Shi, Yixin Li, Lei Gao, Ruize Ma, Weijun Lu, Lulu Xu, Yanpeng Gao, Guiying Li, and Taicheng An
Atmos. Chem. Phys., 24, 3079–3091, https://doi.org/10.5194/acp-24-3079-2024, https://doi.org/10.5194/acp-24-3079-2024, 2024
Short summary
Short summary
The formation mechanisms for secondary brown carbon (SBrC) contributed by multifunctional reduced nitrogen compounds (RNCs) remain unclear. Hence, from combined laboratory experiments and quantum chemical calculations, we investigated the heterogeneous reactions of glyoxal (GL) with multifunctional RNCs, which are driven by four-step indirect nucleophilic addition reactions. Our results show a possible missing source for SBrC formation on urban, regional, and global scales.
Cited articles
Anand, S.: The concern for equity in health, J. Epidemiol. Commun. H., 56, 485–487, 2002.
Arunachalam, S., Holland, A., Do, B., and Abraczinskas, M.: A
quantitative assessment of the influence of grid resolution on predictions of
future-year air quality in North Carolina, USA, Atmos. Environ., 40, 5010–5026, 2006.
Carter, W. P. L.: Documentation of the SAPRC-99 chemical mechanism for VOC reactivity assessment, Final Report to California Air Resources Board Contract 92-329 and Contract 95-308, Air Pollution Research Center and College of Engineering Center for Environmental Research and Technology, University of California Riverside, California, 2000.
Day, M., Pouliot, G., Hunt, S., Baker, K. R., Beardsley, M., Frost, G.,
Mobley, D., Simon, H., Henderson, B., Yelverton, T., and Rao, V.: Reflecting on progress since the 2005 NARSTO emissions inventory report, J. Air Waste Manage., 69, 1025–1050, 2019.
Dinkelacker, B. T., Garcia Rivera, P., Kioutsioukis, I., Adams, P., and Pandis, S. N.: Source Code for PMCAMx-v2.0: High-resolution modeling of fine particulate matter in an urban area using PMCAMx-v2.0, Zenodo [code], https://doi.org/10.5281/zenodo.5094477, 2021.
Dockery, D. W. and Pope, C. A.: Acute respiratory effects of particulate air pollution, Annu. Rev. Publ. Health, 15, 107–132, 1994.
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.
Elessa Etuman, A. and Coll, I.: OLYMPUS v1.0: development of an integrated air
pollutant and GHG urban emissions model – methodology and calibration over greater Paris, Geosci. Model Dev., 11, 5085–5111, https://doi.org/10.5194/gmd-11-5085-2018, 2018.
ENVIRON: CAMx (Comprehensive Air Quality Model with Extensions) User's Guide Version 4.20, 2005.
Eyth, A. and Vukovich, J.: Technical Support Document (TSD) Preparation of Emissions Inventories for the Version 6.3, 2011 Emissions Modeling Platform. US Environmental Protection Agency, Office of Air Quality Planning and Standards, 2016.
Fahey, K. M. and Pandis, S. N.: Optimizing model performance: variable size resolution in cloud chemistry modeling, Atmos. Environ., 35, 4471–4478, 2001.
Fountoukis, C., Racherla, P. N., Denier van der Gon, H. A. C., Polymeneas, P., Charalampidis, P. E., Pilinis, C., Wiedensohler, A., Dall'Osto, M., O'Dowd, C., and Pandis, S. N.: Evaluation of a three-dimensional chemical transport model (PMCAMx) in the European domain during the EUCAARI May 2008 campaign, Atmos. Chem. Phys., 11, 10331–10347, https://doi.org/10.5194/acp-11-10331-2011, 2011.
Fountoukis, C., Koraj, D., Denier van der Gon, H. A. C.,
Charalampidis, P. E., Pilinis, C., and Pandis, S. N.: Impact of grid resolution on
the predicted fine PM by a regional 3-D chemical transport model,
Atmos. Environ., 68, 24–32, 2013.
Gilliam, R. C. and Pleim, J. E.: Performance assessment of new land
surface and planetary boundary layer physics in the
WRF-ARW, J. Appl. Meteorol. Clim., 49, 760–774, 2010.
Gu, P., Li, H. Z., Ye, Q., Robinson, E. S., Apte, J. S.,
Robinson, A. L., and Presto, A. A.: Intracity variability of particulate matter
exposure is driven by carbonaceous sources and correlated with land-use
variables, Environ. Sci. Technol., 52, 11545–11554, 2018.
Hogrefe, C., Pouliot, G., Wong, D., Torian, A., Roselle, S.,
Pleim, J., and Mathur, R.: Annual application and evaluation of the online coupled
WRF-CMAQ system over North America under AQMEII phase 2, Atmos. Environ., 115, 683–694, 2015.
Karydis, V. A., Tsimpidi, A. P., Fountoukis, C., Nenes, A.,
Zavala, M., Lei, W., Molina, L. T., and Pandis, S. N.: Simulating the fine and
coarse inorganic particulate matter concentrations in a polluted
megacity, Atmos. Environ., 44, 608–620, 2010.
Kumar, N. and Russell, A. G.: Multiscale air quality modeling of the
Northeastern United States, Atmos. Environ., 30, 1099–1116, 1996.
Lane, T. E., Donahue, N. M., and Pandis, S. N.: Effect of NOx on
secondary organic aerosol concentrations, Environ. Sci. Technol., 42, 6022–6027, 2008.
Ma, W., Pi, X., and Qian, S.: Estimating multi-class dynamic origin-destination demand through a forward-backward algorithm on computational graphs, Transport. Res. C-Emer., 119, 102747, https://doi.org/10.1016/j.trc.2020.102747, 2020.
McDonald, B. and McBride, Z.: High-resolution mapping of motor vehicle carbon dioxide emissions, J. Geophys. Res., 119, 5283–5298, 2014.
Murphy, B. N. and Pandis, S. N.: Simulating the formation of semivolatile primary and secondary organic aerosol in a regional chemical transport model, Environ. Sci. Technol., 43, 4722–4728, 2009.
Nenes A., Pandis, S. N., and Pilinis, C.: ISORROPIA: A new thermodynamic equilibrium model for multiphase multicomponent inorganic aerosols, Aquat. Geochem., 4, 123–152, 1998.
Pan, S., Choi, Y., Roy, A., and Jeon, W.: Allocating emissions to
4 km and 1 km horizontal spatial resolutions and its impact on
simulated NOx and O3 in Houston, TX, Atmos. Environ., 164, 398–415, 2017.
Pandis, S. N., Wexler, A. S., and Seinfeld, J. H.: Secondary organic aerosol formation and transport – II. Predicting the ambient secondary organic aerosol size distribution, Atmos. Environ., 27, 2403–2416, 1993.
Robinson, E. S., Gu, P., Ye, Q., Li, H. Z., Shah, R. U.,
Apte, J. S., Robinson, A. L., and Presto, A. A.: Restaurant impacts on outdoor air
quality: Elevated organic aerosol mass from restaurant cooking with
neighborhood-scale plume extents, Environ. Sci. Technol., 52, 9285–9294, 2018.
Rogers, R. E., Deng, A., Stauffer, D. R., Gaudet, B. J., Jia, Y.,
Soong, S. T., and Tanrikulu, S.: Application of the weather research and
forecasting model for air quality modeling in the San Francisco bay
area, J. Appl. Meteorol. Clim., 52, 1953–1973, 2013.
Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 2nd edn., John Wiley and Sons, Inc., Hoboken, ISBN: 978-0471720188, 2006.
Stroud, C. A., Makar, P. A., Moran, M. D., Gong, W., Gong, S., Zhang, J., Hayden, K., Mihele, C., Brook, J. R., Abbatt, J. P. D., and Slowik, J. G.: Impact of model grid spacing on regional- and urban-scale air quality predictions of organic aerosol, Atmos. Chem. Phys., 11, 3107–3118, https://doi.org/10.5194/acp-11-3107-2011, 2011.
Tsimpidi, A. P., Karydis, V. A., Zavala, M., Lei, W., Molina, L., Ulbrich, I. M., Jimenez, J. L., and Pandis, S. N.: Evaluation of the volatility basis-set approach for the simulation of organic aerosol formation in the Mexico City metropolitan area, Atmos. Chem. Phys., 10, 525–546, https://doi.org/10.5194/acp-10-525-2010, 2010.
US Environmental Protection Agency: 2011 National Emissions Inventory, version 2: technical support document, US Environmental Protection Agency, Washington, DC, https://www.epa.gov/sites/production/files/2015-10/documents/nei2011v2 (last access: 5 February 2022), 2015.
Ye, Q., Gu, P., Li, H. Z., Robinson, E. S., Lipsky, E., Kaltsounoudis, C.,
Lee, A. K. Y., Apte, J. S., Robinson, A. L., Sullivan, R. C., Presto, A. A.,
and Donahue, N. M.: Spatial variability of sources and mixing state of atmospheric particles in a metropolitan area, Environ. Sci. Technol., 52, 6807–6815, 2018.
Zakoura, M. and Pandis, S. N.:. Overprediction of aerosol nitrate by
chemical transport models: The role of grid resolution, Atmos. Environ., 187, 390–400, 2018.
Zakoura, M. and Pandis, S. N.: Improving fine aerosol nitrate
predictions using a Plume-in-Grid modeling approach, Atmos. Environ., 215, 116887, https://doi.org/10.1016/j.atmosenv.2019.116887, 2019.
Short summary
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.
The contribution of various pollution sources to the variability of fine PM in an urban area was...
Altmetrics
Final-revised paper
Preprint