Articles | Volume 24, issue 23
https://doi.org/10.5194/acp-24-13317-2024
© Author(s) 2024. This work is distributed under
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the Creative Commons Attribution 4.0 License.
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https://doi.org/10.5194/acp-24-13317-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Opinion
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02 Dec 2024
Opinion | Highlight paper |
| 02 Dec 2024
| 02 Dec 2024
Opinion: Challenges and needs of tropospheric chemical mechanism development
Institute of Chemistry, University Clermont Auvergne, CNRS, 63000 Clermont-Ferrand, France
Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
National Centre for Atmospheric Science, University of York, Heslington, York, YO10 5DD, United Kingdom
Bernard Aumont
Univ Paris Est Créteil and Université Paris Cité, CNRS, LISA, 94010 Créteil, France
William P. L. Carter
College of Engineering Center for Environmental Research and Technology (CE-CERT), University of California, Riverside, CA 92521, USA
Max McGillen
Institut de Combustion, Aérothermique, Réactivité Environnement (ICARE), CNRS, 1C Avenue de la Recherche Scientifique, CEDEX 2, 45071 Orléans, France
Abdelwahid Mellouki
Institut de Combustion, Aérothermique, Réactivité Environnement (ICARE), CNRS, 1C Avenue de la Recherche Scientifique, CEDEX 2, 45071 Orléans, France
University Mohammed VI Polytechnic (UM6P), Lot 660, Hay Moulay Rachid Ben Guerir, 43150, Morocco
John Orlando
Atmospheric Chemistry Observations and Modeling Lab, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA
Bénédicte Picquet-Varrault
Univ Paris Est Créteil and Université Paris Cité, CNRS, LISA, 94010 Créteil, France
Paul Seakins
School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
William R. Stockwell
Department of Physics, University of Texas at El Paso, El Paso, TX, USA
Luc Vereecken
Institute of Climate and Energy Systems ICE-3: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
Timothy J. Wallington
Center for Sustainable Systems, School for Environment and Sustainability, University of Michigan, Ann Arbor MI 48109, USA
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Clouds cool our atmosphere. The role of small aerosol particles in affecting them represents one of the largest uncertainties in current estimates of climate change. Traditionally it is assumed that cloud droplets only form particles of diameters ~ 100 nm (
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accumulation mode). Previous studies suggest that this can also occur in smaller particles (
Aitken mode). Our study provides a general framework to estimate under which aerosol and cloud conditions Aitken mode particles affect clouds.
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This article is included in the Encyclopedia of Geosciences
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This work outlines an investigation into an understudied atmospheric chemical reaction pathway with the potential to form particulate pollution that has important impacts on air quality and climate. It suggests that this chemical pathway is responsible for a large fraction of the atmospheric particulate matter observed in tropical forested regions, but also highlights the need for further ambient and lab investigations to inform an accurate representation of this process in atmospheric models.
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Atmos. Chem. Phys., 25, 15715–15740, https://doi.org/10.5194/acp-25-15715-2025, https://doi.org/10.5194/acp-25-15715-2025, 2025
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This article is included in the Encyclopedia of Geosciences
William P. L. Carter, Jia Jiang, Zhizhao Wang, and Kelley C. Barsanti
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The SAPRC Atmospheric Chemical Mechanism Generation System (MechGen) generates explicit chemical reaction mechanisms for organic compounds. MechGen has been used for decades in the development of the widely used SAPRC mechanisms. This paper, detailing the software system, and a companion paper, detailing the chemical basis, represent the first complete documentation of MechGen. This paper includes examples and instructions for generating explicit and reduced mechanisms.
This article is included in the Encyclopedia of Geosciences
Barbara Ervens, Ken S. Carslaw, Thomas Koop, and Ulrich Pöschl
Atmos. Chem. Phys., 25, 13903–13952, https://doi.org/10.5194/acp-25-13903-2025, https://doi.org/10.5194/acp-25-13903-2025, 2025
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Over 25 years, the European Geosciences Union (EGU) has demonstrated the success, viability and benefits of interactive open-access (OA) publishing with public peer review in its journals, its publishing platform EGUsphere and virtual compilations. The article summarizes the evolution of the EGU/Copernicus publications and of OA publishing with interactive public peer review at large by placing the EGU/Copernicus publications in the context of current and future global open science.
This article is included in the Encyclopedia of Geosciences
Simone T. Andersen, Rolf Sander, Patrick Dewald, Laura Wüst, Tobias Seubert, Gunther N. T. E. Türk, Jan Schuladen, Max R. McGillen, Chaoyang Xue, Abdelwahid Mellouki, Alexandre Kukui, Vincent Michoud, Manuela Cirtog, Mathieu Cazaunau, Astrid Bauville, Hichem Bouzidi, Paola Formenti, Cyrielle Denjean, Jean-Claude Etienne, Olivier Garrouste, Christopher Cantrell, Jos Lelieveld, and John N. Crowley
Atmos. Chem. Phys., 25, 5893–5909, https://doi.org/10.5194/acp-25-5893-2025, https://doi.org/10.5194/acp-25-5893-2025, 2025
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Measurements and modelling of reactive nitrogen gases observed in a suburban temperate forest in Rambouillet, France, circa 50 km southwest of Paris in 2022 indicate that the biosphere rapidly scavenges organic nitrates of mixed biogenic and anthropogenic origin, resulting in short lifetimes for, for example, alkyl nitrates and peroxy nitrates.
This article is included in the Encyclopedia of Geosciences
Rhianna L. Evans, Daniel J. Bryant, Aristeidis Voliotis, Dawei Hu, Huihui Wu, Sara Aisyah Syafira, Osayomwanbor E. Oghama, Gordon McFiggans, Jacqueline F. Hamilton, and Andrew R. Rickard
Atmos. Chem. Phys., 25, 4367–4389, https://doi.org/10.5194/acp-25-4367-2025, https://doi.org/10.5194/acp-25-4367-2025, 2025
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The chemical composition of organic aerosol derived from wood-burning emissions under different burning conditions was characterised. Fresh emissions from flaming and smouldering were largely aromatic in nature, whereas upon aging the aromatic content decreased. This decrease was greater for smouldering due to the loss of toxic polyaromatic species, whereas under flaming conditions highly toxic polyaromatic species were produced. These differences present an important challenge for future policy.
This article is included in the Encyclopedia of Geosciences
Raphaëlle Péguilhan, Florent Rossi, Muriel Joly, Engy Nasr, Bérénice Batut, François Enault, Barbara Ervens, and Pierre Amato
Biogeosciences, 22, 1257–1275, https://doi.org/10.5194/bg-22-1257-2025, https://doi.org/10.5194/bg-22-1257-2025, 2025
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Using comparative metagenomics and metatranscriptomics, we examined the functioning of airborne microorganisms in clouds and a clear atmosphere. Clouds are atmospheric masses where multiple microbial processes are promoted compared with a clear atmosphere. Overrepresented microbial functions of interest include the processing of chemical compounds, biomass production, and regulation of oxidants. This has implications for biogeochemical cycles and microbial ecology.
This article is included in the Encyclopedia of Geosciences
Barbara Ervens, Pierre Amato, Kifle Aregahegn, Muriel Joly, Amina Khaled, Tiphaine Labed-Veydert, Frédéric Mathonat, Leslie Nuñez López, Raphaëlle Péguilhan, and Minghui Zhang
Biogeosciences, 22, 243–256, https://doi.org/10.5194/bg-22-243-2025, https://doi.org/10.5194/bg-22-243-2025, 2025
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Atmospheric microorganisms are a small fraction of Earth's microbiome, with bacteria being a significant part. Aerosolized bacteria are airborne for a few days, encountering unique chemical and physical conditions affecting stress levels and survival. We explore chemical and microphysical conditions bacteria encounter, highlighting potential nutrient and oxidant limitations and diverse effects by pollutants, which may ultimately impact the microbiome's role in global ecosystems and biodiversity.
This article is included in the Encyclopedia of Geosciences
William P. L. Carter, Jia Jiang, John J. Orlando, and Kelley C. Barsanti
Atmos. Chem. Phys., 25, 199–242, https://doi.org/10.5194/acp-25-199-2025, https://doi.org/10.5194/acp-25-199-2025, 2025
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This paper describes the scientific basis for gas-phase atmospheric chemical mechanisms derived using the SAPRC mechanism generation system, MechGen. It can derive mechanisms for most organic compounds with C, H, O, or N atoms, including initial reactions of organics with OH, O3, NO3, and O3P or by photolysis, as well as the reactions of the various types of intermediates that are formed. The paper includes a description of areas of uncertainty where additional research and updates are needed.
This article is included in the Encyclopedia of Geosciences
Christopher Lawrence, Mary Barth, John Orlando, Paul Casson, Richard Brandt, Daniel Kelting, Elizabeth Yerger, and Sara Lance
Atmos. Chem. Phys., 24, 13693–13713, https://doi.org/10.5194/acp-24-13693-2024, https://doi.org/10.5194/acp-24-13693-2024, 2024
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This work uses chemical transport and box modeling to study the gas- and aqueous-phase production of organic acid concentrations measured in cloud water at the summit of Whiteface Mountain on 1 July 2018. Isoprene was the major source of formic, acetic, and oxalic acid. Gas-phase chemistry greatly underestimated formic and acetic acid, indicating missing sources, while cloud chemistry was a key source of oxalic acid. More studies of organic acids are required to better constrain their sources.
This article is included in the Encyclopedia of Geosciences
Lauri Franzon, Marie Camredon, Richard Valorso, Bernard Aumont, and Theo Kurtén
Atmos. Chem. Phys., 24, 11679–11699, https://doi.org/10.5194/acp-24-11679-2024, https://doi.org/10.5194/acp-24-11679-2024, 2024
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In this article we investigate the formation of large, sticky molecules from various organic compounds entering the atmosphere as primary emissions and the degree to which these processes may contribute to organic aerosol particle mass. More specifically, we qualitatively investigate a recently discovered chemical reaction channel for one of the most important short-lived radical compounds, peroxy radicals, and discover which of these reactions are most atmospherically important.
This article is included in the Encyclopedia of Geosciences
Simone T. Andersen, Max R. McGillen, Chaoyang Xue, Tobias Seubert, Patrick Dewald, Gunther N. T. E. Türk, Jan Schuladen, Cyrielle Denjean, Jean-Claude Etienne, Olivier Garrouste, Marina Jamar, Sergio Harb, Manuela Cirtog, Vincent Michoud, Mathieu Cazaunau, Antonin Bergé, Christopher Cantrell, Sebastien Dusanter, Bénédicte Picquet-Varrault, Alexandre Kukui, Abdelwahid Mellouki, Lucy J. Carpenter, Jos Lelieveld, and John N. Crowley
Atmos. Chem. Phys., 24, 11603–11618, https://doi.org/10.5194/acp-24-11603-2024, https://doi.org/10.5194/acp-24-11603-2024, 2024
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Using measurements of various trace gases in a suburban forest near Paris in the summer of 2022, we were able to gain insight into the sources and sinks of NOx (NO+NO2) with a special focus on their nighttime chemical and physical loss processes. NO was observed as a result of nighttime soil emissions when O3 levels were strongly depleted by deposition. NO oxidation products were not observed at night, indicating that soil and/or foliar surfaces are an efficient sink of reactive N.
This article is included in the Encyclopedia of Geosciences
Beth S. Nelson, Zhenze Liu, Freya A. Squires, Marvin Shaw, James R. Hopkins, Jacqueline F. Hamilton, Andrew R. Rickard, Alastair C. Lewis, Zongbo Shi, and James D. Lee
Atmos. Chem. Phys., 24, 9031–9044, https://doi.org/10.5194/acp-24-9031-2024, https://doi.org/10.5194/acp-24-9031-2024, 2024
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The impact of combined air quality and carbon neutrality policies on O3 formation in Beijing was investigated. Emissions inventory data were used to estimate future pollutant mixing ratios relative to ground-level observations. O3 production was found to be most sensitive to changes in alkenes, but large reductions in less reactive compounds led to larger reductions in future O3 production. This study highlights the importance of understanding the emissions of organic pollutants.
This article is included in the Encyclopedia of Geosciences
Patrick Dewald, Tobias Seubert, Simone T. Andersen, Gunther N. T. E. Türk, Jan Schuladen, Max R. McGillen, Cyrielle Denjean, Jean-Claude Etienne, Olivier Garrouste, Marina Jamar, Sergio Harb, Manuela Cirtog, Vincent Michoud, Mathieu Cazaunau, Antonin Bergé, Christopher Cantrell, Sebastien Dusanter, Bénédicte Picquet-Varrault, Alexandre Kukui, Chaoyang Xue, Abdelwahid Mellouki, Jos Lelieveld, and John N. Crowley
Atmos. Chem. Phys., 24, 8983–8997, https://doi.org/10.5194/acp-24-8983-2024, https://doi.org/10.5194/acp-24-8983-2024, 2024
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In the scope of a field campaign in a suburban forest near Paris in the summer of 2022, we measured the reactivity of the nitrate radical NO3 towards biogenic volatile organic compounds (BVOCs; e.g. monoterpenes) mainly below but also above the canopy. NO3 reactivity was the highest during nights with strong temperature inversions and decreased strongly with height. Reactions with BVOCs were the main removal process of NO3 throughout the diel cycle below the canopy.
This article is included in the Encyclopedia of Geosciences
David P. Edwards, Sara Martínez-Alonso, Duseong S. Jo, Ivan Ortega, Louisa K. Emmons, John J. Orlando, Helen M. Worden, Jhoon Kim, Hanlim Lee, Junsung Park, and Hyunkee Hong
Atmos. Chem. Phys., 24, 8943–8961, https://doi.org/10.5194/acp-24-8943-2024, https://doi.org/10.5194/acp-24-8943-2024, 2024
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Until recently, satellite observations of atmospheric pollutants at any location could only be obtained once a day. New geostationary satellites stare at a region of the Earth to make hourly measurements, and the Geostationary Environment Monitoring Spectrometer is the first looking at Asia. These data and model simulations show how the change seen for one important pollutant that determines air quality depends on a combination of pollution emissions, atmospheric chemistry, and meteorology.
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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
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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.
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Leslie Nuñez López, Pierre Amato, and Barbara Ervens
Atmos. Chem. Phys., 24, 5181–5198, https://doi.org/10.5194/acp-24-5181-2024, https://doi.org/10.5194/acp-24-5181-2024, 2024
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Living bacteria comprise a small particle fraction in the atmosphere. Our model study shows that atmospheric bacteria in clouds may efficiently biodegrade formic and acetic acids that affect the acidity of rain. We conclude that current atmospheric models underestimate losses of these acids as they only consider chemical processes. We suggest that biodegradation can affect atmospheric concentration not only of formic and acetic acids but also of other volatile, moderately soluble organics.
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Ernst-Peter Röth and Luc Vereecken
Atmos. Chem. Phys., 24, 2625–2638, https://doi.org/10.5194/acp-24-2625-2024, https://doi.org/10.5194/acp-24-2625-2024, 2024
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The paper presents the radical and molecular product quantum yields in the photolysis reaction of CHDO at wavelengths above 300 nm. Two different approaches based on literature data are used, with results falling within both approaches' uncertainty ranges. Simple functional forms are presented for use in photochemical models of the atmosphere.
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Frank A. F. Winiberg, William J. Warman, Charlotte A. Brumby, Graham Boustead, Iustinian G. Bejan, Thomas H. Speak, Dwayne E. Heard, Daniel Stone, and Paul W. Seakins
Atmos. Meas. Tech., 16, 4375–4390, https://doi.org/10.5194/amt-16-4375-2023, https://doi.org/10.5194/amt-16-4375-2023, 2023
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OH and HO2 are key reactive intermediates in the Earth's atmosphere. Accurate measurements in either the field or simulation chambers provide a good test for chemical mechanisms. Fluorescence techniques have the appropriate sensitivity for detection but require calibration. This paper compares different methods of calibration and specifically how calibration factors vary across a temperature range relevant to atmospheric and chamber determinations.
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Bryan K. Place, William T. Hutzell, K. Wyat Appel, Sara Farrell, Lukas Valin, Benjamin N. Murphy, Karl M. Seltzer, Golam Sarwar, Christine Allen, Ivan R. Piletic, Emma L. D'Ambro, Emily Saunders, Heather Simon, Ana Torres-Vasquez, Jonathan Pleim, Rebecca H. Schwantes, Matthew M. Coggon, Lu Xu, William R. Stockwell, and Havala O. T. Pye
Atmos. Chem. Phys., 23, 9173–9190, https://doi.org/10.5194/acp-23-9173-2023, https://doi.org/10.5194/acp-23-9173-2023, 2023
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Ground-level ozone is a pollutant with adverse human health and ecosystem effects. Air quality models allow scientists to understand the chemical production of ozone and demonstrate impacts of air quality management plans. In this work, the role of multiple systems in ozone production was investigated for the northeastern US in summer. Model updates to chemical reaction rates and monoterpene chemistry were most influential in decreasing predicted ozone and improving agreement with observations.
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Caterina Mapelli, James K. Donnelly, Úna E. Hogan, Andrew R. Rickard, Abbie T. Robinson, Fergal Byrne, Con Rob McElroy, Basile F. E. Curchod, Daniel Hollas, and Terry J. Dillon
Atmos. Chem. Phys., 23, 7767–7779, https://doi.org/10.5194/acp-23-7767-2023, https://doi.org/10.5194/acp-23-7767-2023, 2023
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Solvents are chemical compounds with countless uses in the chemical industry, and they also represent one of the main sources of pollution in the chemical sector. Scientists are trying to develop new
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greensafer solvents which present favourable advantages when compared to traditional solvents. Since the assessment of these green solvents often lacks air quality considerations, this study aims to understand the behaviour of these compounds, investigating their reactivity in the troposphere.
Hao Luo, Luc Vereecken, Hongru Shen, Sungah Kang, Iida Pullinen, Mattias Hallquist, Hendrik Fuchs, Andreas Wahner, Astrid Kiendler-Scharr, Thomas F. Mentel, and Defeng Zhao
Atmos. Chem. Phys., 23, 7297–7319, https://doi.org/10.5194/acp-23-7297-2023, https://doi.org/10.5194/acp-23-7297-2023, 2023
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Oxidation of limonene, an element emitted by trees and chemical products, by OH, a daytime oxidant, forms many highly oxygenated organic molecules (HOMs), including C10-20 compounds. HOMs play an important role in new particle formation and growth. HOM formation can be explained by the chemistry of peroxy radicals. We found that a minor branching ratio initial pathway plays an unexpected, significant role. Considering this pathway enables accurate simulations of HOMs and other concentrations.
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Havala O. T. Pye, Bryan K. Place, Benjamin N. Murphy, Karl M. Seltzer, Emma L. D'Ambro, Christine Allen, Ivan R. Piletic, Sara Farrell, Rebecca H. Schwantes, Matthew M. Coggon, Emily Saunders, Lu Xu, Golam Sarwar, William T. Hutzell, Kristen M. Foley, George Pouliot, Jesse Bash, and William R. Stockwell
Atmos. Chem. Phys., 23, 5043–5099, https://doi.org/10.5194/acp-23-5043-2023, https://doi.org/10.5194/acp-23-5043-2023, 2023
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Chemical mechanisms describe how emissions from vehicles, vegetation, and other sources are chemically transformed in the atmosphere to secondary products including criteria and hazardous air pollutants. The Community Regional Atmospheric Chemistry Multiphase Mechanism integrates gas-phase radical chemistry with pathways to fine-particle mass. New species were implemented, resulting in a bottom-up representation of organic aerosol, which is required for accurate source attribution of pollutants.
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Philip T. M. Carlsson, Luc Vereecken, Anna Novelli, François Bernard, Steven S. Brown, Bellamy Brownwood, Changmin Cho, John N. Crowley, Patrick Dewald, Peter M. Edwards, Nils Friedrich, Juliane L. Fry, Mattias Hallquist, Luisa Hantschke, Thorsten Hohaus, Sungah Kang, Jonathan Liebmann, Alfred W. Mayhew, Thomas Mentel, David Reimer, Franz Rohrer, Justin Shenolikar, Ralf Tillmann, Epameinondas Tsiligiannis, Rongrong Wu, Andreas Wahner, Astrid Kiendler-Scharr, and Hendrik Fuchs
Atmos. Chem. Phys., 23, 3147–3180, https://doi.org/10.5194/acp-23-3147-2023, https://doi.org/10.5194/acp-23-3147-2023, 2023
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The investigation of the night-time oxidation of the most abundant hydrocarbon, isoprene, in chamber experiments shows the importance of reaction pathways leading to epoxy products, which could enhance particle formation, that have so far not been accounted for. The chemical lifetime of organic nitrates from isoprene is long enough for the majority to be further oxidized the next day by daytime oxidants.
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Nakul N. Karle, Ricardo K. Sakai, Rosa M. Fitzgerald, Charles Ichoku, Fernando Mercado, and William R. Stockwell
Atmos. Meas. Tech., 16, 1073–1085, https://doi.org/10.5194/amt-16-1073-2023, https://doi.org/10.5194/amt-16-1073-2023, 2023
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Extensive virga research is uncommon, even though it is a common phenomenon. A systematic method was developed to characterize virga using available datasets. In total, 50 virga events were observed, appearing only during a specific time of the year, revealing a seasonal pattern. These virga events were identified and classified, and their impact on surface PM measurements was investigated. A more detailed examination of the selected events reveals that virga impacts regional air quality.
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Daniel J. Bryant, Beth S. Nelson, Stefan J. Swift, Sri Hapsari Budisulistiorini, Will S. Drysdale, Adam R. Vaughan, Mike J. Newland, James R. Hopkins, James M. Cash, Ben Langford, Eiko Nemitz, W. Joe F. Acton, C. Nicholas Hewitt, Tuhin Mandal, Bhola R. Gurjar, Shivani, Ranu Gadi, James D. Lee, Andrew R. Rickard, and Jacqueline F. Hamilton
Atmos. Chem. Phys., 23, 61–83, https://doi.org/10.5194/acp-23-61-2023, https://doi.org/10.5194/acp-23-61-2023, 2023
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This paper investigates the sources of isoprene and monoterpene compounds and their particulate-phase oxidation products in Delhi, India. This was done to improve our understanding of the sources, concentrations, and fate of volatile emissions in megacities. By studying the chemical composition of offline filter samples, we report that a significant share of the oxidised organic aerosol in Delhi is from isoprene and monoterpenes. This has implications for human health and policy development.
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Alfred W. Mayhew, Ben H. Lee, Joel A. Thornton, Thomas J. Bannan, James Brean, James R. Hopkins, James D. Lee, Beth S. Nelson, Carl Percival, Andrew R. Rickard, Marvin D. Shaw, Peter M. Edwards, and Jaqueline F. Hamilton
Atmos. Chem. Phys., 22, 14783–14798, https://doi.org/10.5194/acp-22-14783-2022, https://doi.org/10.5194/acp-22-14783-2022, 2022
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Isoprene nitrates are chemical species commonly found in the atmosphere that are important for their impacts on air quality and climate. This paper compares 3 different representations of the chemistry of isoprene nitrates in computational models highlighting cases where the choice of chemistry included has significant impacts on the concentration and composition of the modelled nitrates. Calibration of mass spectrometers is also shown to be an important factor when analysing isoprene nitrates.
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Yindong Guo, Hongru Shen, Iida Pullinen, Hao Luo, Sungah Kang, Luc Vereecken, Hendrik Fuchs, Mattias Hallquist, Ismail-Hakki Acir, Ralf Tillmann, Franz Rohrer, Jürgen Wildt, Astrid Kiendler-Scharr, Andreas Wahner, Defeng Zhao, and Thomas F. Mentel
Atmos. Chem. Phys., 22, 11323–11346, https://doi.org/10.5194/acp-22-11323-2022, https://doi.org/10.5194/acp-22-11323-2022, 2022
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The oxidation of limonene, a common volatile emitted by trees and chemical products, by NO3, a nighttime oxidant, forms many highly oxygenated organic molecules (HOM), including C10-30 compounds. Most of the HOM are second-generation organic nitrates, in which carbonyl-substituted C10 nitrates accounted for a major fraction. Their formation can be explained by chemistry of peroxy radicals. HOM, especially low-volatile ones, play an important role in nighttime new particle formation and growth.
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Emily B. Franklin, Lindsay D. Yee, Bernard Aumont, Robert J. Weber, Paul Grigas, and Allen H. Goldstein
Atmos. Meas. Tech., 15, 3779–3803, https://doi.org/10.5194/amt-15-3779-2022, https://doi.org/10.5194/amt-15-3779-2022, 2022
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The composition of atmospheric aerosols are extremely complex, containing hundreds of thousands of estimated individual compounds. The majority of these compounds have never been catalogued in widely used databases, making them extremely difficult for atmospheric chemists to identify and analyze. In this work, we present Ch3MS-RF, a machine-learning-based model to enable characterization of complex mixtures and prediction of structure-specific properties of unidentifiable organic compounds.
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Mike J. Newland, Camille Mouchel-Vallon, Richard Valorso, Bernard Aumont, Luc Vereecken, Michael E. Jenkin, and Andrew R. Rickard
Atmos. Chem. Phys., 22, 6167–6195, https://doi.org/10.5194/acp-22-6167-2022, https://doi.org/10.5194/acp-22-6167-2022, 2022
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Alkene ozonolysis produces Criegee intermediates, which can act as oxidants or decompose to give a range of closed-shell and radical products, including OH. Therefore it is essential to accurately represent the chemistry of Criegee intermediates in atmospheric models in order to understand their impacts on atmospheric composition. Here we provide a mechanism construction protocol by which the central features of alkene ozonolysis chemistry can be included in an automatic mechanism generator.
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Zara S. Mir, Matthew Jamieson, Nicholas R. Greenall, Paul W. Seakins, Mark A. Blitz, and Daniel Stone
Atmos. Meas. Tech., 15, 2875–2887, https://doi.org/10.5194/amt-15-2875-2022, https://doi.org/10.5194/amt-15-2875-2022, 2022
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In this work we describe the development and characterisation of an experiment using laser flash photolysis coupled with time-resolved mid-infrared (mid-IR) quantum cascade laser (QCL) absorption spectroscopy, with initial results reported for measurements of the infrared spectrum, kinetics, and product yields for the reaction of the CH2OO Criegee intermediate with SO2. This work has significance for the identification and measurement of reactive trace species in complex systems.
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Lucien Froidevaux, Douglas E. Kinnison, Michelle L. Santee, Luis F. Millán, Nathaniel J. Livesey, William G. Read, Charles G. Bardeen, John J. Orlando, and Ryan A. Fuller
Atmos. Chem. Phys., 22, 4779–4799, https://doi.org/10.5194/acp-22-4779-2022, https://doi.org/10.5194/acp-22-4779-2022, 2022
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We analyze satellite-derived distributions of chlorine monoxide (ClO) and hypochlorous acid (HOCl) in the upper atmosphere. For 2005–2020, from 50°S to 50°N and over ~30 to 45 km, ClO and HOCl decreased by −0.7 % and −0.4 % per year, respectively. A detailed model of chemistry and dynamics agrees with the results. These decreases confirm the effectiveness of the 1987 Montreal Protocol, which limited emissions of chlorine- and bromine-containing source gases, in order to protect the ozone layer.
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Chaoyang Xue, Can Ye, Jörg Kleffmann, Chenglong Zhang, Valéry Catoire, Fengxia Bao, Abdelwahid Mellouki, Likun Xue, Jianmin Chen, Keding Lu, Yong Zhao, Hengde Liu, Zhaoxin Guo, and Yujing Mu
Atmos. Chem. Phys., 22, 3149–3167, https://doi.org/10.5194/acp-22-3149-2022, https://doi.org/10.5194/acp-22-3149-2022, 2022
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Summertime measurements of nitrous acid (HONO) and related parameters were conducted at the foot and the summit of Mt. Tai (1534 m above sea level). We proposed a rapid vertical air mass exchange between the foot and the summit level, which enhances the role of HONO in the oxidizing capacity of the upper boundary layer. Kinetics for aerosol-derived HONO sources were constrained. HONO formation from different paths was quantified and discussed.
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Amina Khaled, Minghui Zhang, and Barbara Ervens
Atmos. Chem. Phys., 22, 1989–2009, https://doi.org/10.5194/acp-22-1989-2022, https://doi.org/10.5194/acp-22-1989-2022, 2022
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Chemical reactions with iron in clouds and aerosol form and cycle reactive oxygen species (ROS). Previous model studies assumed that all cloud droplets (particles) contain iron, while single-particle analyses showed otherwise. By means of a model, we explore the bias in predicted ROS budgets by distributing a given iron mass to either all or only a few droplets (particles). Implications for oxidation potential, radical loss and iron oxidation state are discussed.
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Mike J. Newland, Yangang Ren, Max R. McGillen, Lisa Michelat, Véronique Daële, and Abdelwahid Mellouki
Atmos. Chem. Phys., 22, 1761–1772, https://doi.org/10.5194/acp-22-1761-2022, https://doi.org/10.5194/acp-22-1761-2022, 2022
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Wildfires are increasing in extent and severity, driven by climate change. Such fires emit large amounts of volatile organic compounds (VOCs) to the atmosphere. Many of these, such as the furans studied here, are very reactive and are rapidly converted to other VOCs, which are expected to have negative health effects and to further impact the climate. Here, we establish the importance of the nitrate radical for removing these compounds both during the night and during the day.
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Chaoyang Xue, Can Ye, Jörg Kleffmann, Wenjin Zhang, Xiaowei He, Pengfei Liu, Chenglong Zhang, Xiaoxi Zhao, Chengtang Liu, Zhuobiao Ma, Junfeng Liu, Jinhe Wang, Keding Lu, Valéry Catoire, Abdelwahid Mellouki, and Yujing Mu
Atmos. Chem. Phys., 22, 1035–1057, https://doi.org/10.5194/acp-22-1035-2022, https://doi.org/10.5194/acp-22-1035-2022, 2022
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Nitrous acid (HONO) and related parameters were measured at the foot and the summit of Mt. Tai in the summer of 2018. Based on measurements at the foot station, we utilized a box model to explore the roles of different sources in the HONO budget. We also studied radical chemistry in this high-ozone region.
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Ramon Campos Braga, Barbara Ervens, Daniel Rosenfeld, Meinrat O. Andreae, Jan-David Förster, Daniel Fütterer, Lianet Hernández Pardo, Bruna A. Holanda, Tina Jurkat-Witschas, Ovid O. Krüger, Oliver Lauer, Luiz A. T. Machado, Christopher Pöhlker, Daniel Sauer, Christiane Voigt, Adrian Walser, Manfred Wendisch, Ulrich Pöschl, and Mira L. Pöhlker
Atmos. Chem. Phys., 21, 17513–17528, https://doi.org/10.5194/acp-21-17513-2021, https://doi.org/10.5194/acp-21-17513-2021, 2021
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Interactions of aerosol particles with clouds represent a large uncertainty in estimates of climate change. Properties of aerosol particles control their ability to act as cloud condensation nuclei. Using aerosol measurements in the Amazon, we performed model studies to compare predicted and measured cloud droplet number concentrations at cloud bases. Our results confirm previous estimates of particle hygroscopicity in this region.
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Zhe Peng, Julia Lee-Taylor, Harald Stark, John J. Orlando, Bernard Aumont, and Jose L. Jimenez
Atmos. Chem. Phys., 21, 14649–14669, https://doi.org/10.5194/acp-21-14649-2021, https://doi.org/10.5194/acp-21-14649-2021, 2021
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We use the fully explicit GECKO-A model to study the OH reactivity (OHR) evolution in the NO-free photooxidation of several volatile organic compounds. Oxidation progressively produces more saturated and functionalized species, then breaks them into small species. OHR per C atom evolution is similar for different precursors once saturated multifunctional species are formed. We also find that partitioning of these species to chamber walls leads to large deviations in chambers from the atmosphere.
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Philipp G. Eger, Luc Vereecken, Rolf Sander, Jan Schuladen, Nicolas Sobanski, Horst Fischer, Einar Karu, Jonathan Williams, Ville Vakkari, Tuukka Petäjä, Jos Lelieveld, Andrea Pozzer, and John N. Crowley
Atmos. Chem. Phys., 21, 14333–14349, https://doi.org/10.5194/acp-21-14333-2021, https://doi.org/10.5194/acp-21-14333-2021, 2021
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We determine the impact of pyruvic acid photolysis on the formation of acetaldehyde and peroxy radicals during summer and autumn in the Finnish boreal forest using a data-constrained box model. Our results are dependent on the chosen scenario in which the overall quantum yield and the photolysis products are varied. We highlight that pyruvic acid photolysis can be an important contributor to acetaldehyde and peroxy radical formation in remote, forested regions.
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Ramon Campos Braga, Daniel Rosenfeld, Ovid O. Krüger, Barbara Ervens, Bruna A. Holanda, Manfred Wendisch, Trismono Krisna, Ulrich Pöschl, Meinrat O. Andreae, Christiane Voigt, and Mira L. Pöhlker
Atmos. Chem. Phys., 21, 14079–14088, https://doi.org/10.5194/acp-21-14079-2021, https://doi.org/10.5194/acp-21-14079-2021, 2021
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Quantifying the precipitation within clouds is crucial for our understanding of the Earth's hydrological cycle. Using in situ measurements of cloud and rain properties over the Amazon Basin and Atlantic Ocean, we show here a linear relationship between the effective radius (re) and precipitation water content near the tops of convective clouds for different pollution states and temperature levels. Our results emphasize the role of re to determine both initiation and amount of precipitation.
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Beth S. Nelson, Gareth J. Stewart, Will S. Drysdale, Mike J. Newland, Adam R. Vaughan, Rachel E. Dunmore, Pete M. Edwards, Alastair C. Lewis, Jacqueline F. Hamilton, W. Joe Acton, C. Nicholas Hewitt, Leigh R. Crilley, Mohammed S. Alam, Ülkü A. Şahin, David C. S. Beddows, William J. Bloss, Eloise Slater, Lisa K. Whalley, Dwayne E. Heard, James M. Cash, Ben Langford, Eiko Nemitz, Roberto Sommariva, Sam Cox, Shivani, Ranu Gadi, Bhola R. Gurjar, James R. Hopkins, Andrew R. Rickard, and James D. Lee
Atmos. Chem. Phys., 21, 13609–13630, https://doi.org/10.5194/acp-21-13609-2021, https://doi.org/10.5194/acp-21-13609-2021, 2021
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Ozone production at an urban site in Delhi is sensitive to volatile organic compound (VOC) concentrations, particularly those of the aromatic, monoterpene, and alkene VOC classes. The change in ozone production by varying atmospheric pollutants according to their sources, as defined in an emissions inventory, is investigated. The study suggests that reducing road transport emissions alone does not reduce reactive VOCs in the atmosphere enough to perturb an increase in ozone production.
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Yangang Ren, Li Zhou, Abdelwahid Mellouki, Véronique Daële, Mahmoud Idir, Steven S. Brown, Branko Ruscic, Robert S. Paton, Max R. McGillen, and A. R. Ravishankara
Atmos. Chem. Phys., 21, 13537–13551, https://doi.org/10.5194/acp-21-13537-2021, https://doi.org/10.5194/acp-21-13537-2021, 2021
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Aromatic aldehydes are a family of compounds emitted into the atmosphere from both anthropogenic and biogenic sources that are formed from the degradation of aromatic hydrocarbons. Their atmospheric degradation may impact air quality. We report on their atmospheric degradation through reaction with NO3, which is useful to estimate their atmospheric lifetimes. We have also attempted to elucidate the mechanism of these reactions via studies of isotopic substitution and quantum chemistry.
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R. Anthony Cox, Markus Ammann, John N. Crowley, Paul T. Griffiths, Hartmut Herrmann, Erik H. Hoffmann, Michael E. Jenkin, V. Faye McNeill, Abdelwahid Mellouki, Christopher J. Penkett, Andreas Tilgner, and Timothy J. Wallington
Atmos. Chem. Phys., 21, 13011–13018, https://doi.org/10.5194/acp-21-13011-2021, https://doi.org/10.5194/acp-21-13011-2021, 2021
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The term open-air factor was coined in the 1960s, establishing that rural air had powerful germicidal properties possibly resulting from immediate products of the reaction of ozone with alkenes, unsaturated compounds ubiquitously present in natural and polluted environments. We have re-evaluated those early experiments, applying the recently substantially improved knowledge, and put them into the context of the lifetime of aerosol-borne pathogens that are so important in the Covid-19 pandemic.
This article is included in the Encyclopedia of Geosciences
Mira L. Pöhlker, Minghui Zhang, Ramon Campos Braga, Ovid O. Krüger, Ulrich Pöschl, and Barbara Ervens
Atmos. Chem. Phys., 21, 11723–11740, https://doi.org/10.5194/acp-21-11723-2021, https://doi.org/10.5194/acp-21-11723-2021, 2021
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Clouds cool our atmosphere. The role of small aerosol particles in affecting them represents one of the largest uncertainties in current estimates of climate change. Traditionally it is assumed that cloud droplets only form particles of diameters ~ 100 nm (
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accumulation mode). Previous studies suggest that this can also occur in smaller particles (
Aitken mode). Our study provides a general framework to estimate under which aerosol and cloud conditions Aitken mode particles affect clouds.
Isaac Kwadjo Afreh, Bernard Aumont, Marie Camredon, and Kelley Claire Barsanti
Atmos. Chem. Phys., 21, 11467–11487, https://doi.org/10.5194/acp-21-11467-2021, https://doi.org/10.5194/acp-21-11467-2021, 2021
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This is the first mechanistic modeling study of secondary organic aerosol (SOA) from the understudied monoterpene, camphene. The semi-explicit chemical model GECKO-A predicted camphene SOA yields that were ~2 times α-pinene. Using 50/50 α-pinene + limonene as a surrogate for camphene increased predicted SOA mass from biomass burning fuels by up to ~100 %. The accurate representation of camphene in air quality models can improve predictions of SOA when camphene is a dominant monoterpene.
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Yingnan Zhang, Likun Xue, William P. L. Carter, Chenglei Pei, Tianshu Chen, Jiangshan Mu, Yujun Wang, Qingzhu Zhang, and Wenxing Wang
Atmos. Chem. Phys., 21, 11053–11068, https://doi.org/10.5194/acp-21-11053-2021, https://doi.org/10.5194/acp-21-11053-2021, 2021
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We developed the localized incremental reactivity (IR) for VOCs in a Chinese megacity and elucidated their applications in calculating the ozone formation potential (OFP). The IR scales showed a strong dependence on chemical mechanisms. Both emission- and observation-based inputs are suitable for the MIR calculation but not the case under mixed-limited or NOx-limited O3 formation regimes. We provide suggestions for the application of IR and OFP scales to aid in VOC control in China.
This article is included in the Encyclopedia of Geosciences
Caterina Mogno, Paul I. Palmer, Christoph Knote, Fei Yao, and Timothy J. Wallington
Atmos. Chem. Phys., 21, 10881–10909, https://doi.org/10.5194/acp-21-10881-2021, https://doi.org/10.5194/acp-21-10881-2021, 2021
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We use a 3-D atmospheric chemistry model to investigate how seasonal emissions sources and meteorological conditions affect the surface distribution of fine particulate matter (PM2.5) and organic aerosol (OA) over the Indo-Gangetic Plain. We find that all seasonal mean values of PM2.5 still exceed safe air quality levels, with human emissions contributing to PM2.5 all year round, open fires during post- and pre-monsoon, and biogenic emissions during monsoon. OA contributes up to 30 % to PM2.5.
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Esther Borrás, Luis A. Tortajada-Genaro, Milagro Ródenas, Teresa Vera, Thomas Speak, Paul Seakins, Marvin D. Shaw, Alastair C. Lewis, and Amalia Muñoz
Atmos. Meas. Tech., 14, 4989–4999, https://doi.org/10.5194/amt-14-4989-2021, https://doi.org/10.5194/amt-14-4989-2021, 2021
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This work presents promising results in the characterization of specific atmospheric pollutants (oxygenated VOCs) present at very low but highly relevant concentrations.
We carried out this research at EUPHORE facilities within the framework of the EUROCHAMP project. A new analytical method, with high robustness and precision, also clean in the use of solvents, low cost, and easily adaptable for use in mobile laboratories for air quality monitoring, is presented.
This article is included in the Encyclopedia of Geosciences
Rongrong Wu, Luc Vereecken, Epameinondas Tsiligiannis, Sungah Kang, Sascha R. Albrecht, Luisa Hantschke, Defeng Zhao, Anna Novelli, Hendrik Fuchs, Ralf Tillmann, Thorsten Hohaus, Philip T. M. Carlsson, Justin Shenolikar, François Bernard, John N. Crowley, Juliane L. Fry, Bellamy Brownwood, Joel A. Thornton, Steven S. Brown, Astrid Kiendler-Scharr, Andreas Wahner, Mattias Hallquist, and Thomas F. Mentel
Atmos. Chem. Phys., 21, 10799–10824, https://doi.org/10.5194/acp-21-10799-2021, https://doi.org/10.5194/acp-21-10799-2021, 2021
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Isoprene is the biogenic volatile organic compound with the largest emissions rates. The nighttime reaction of isoprene with the NO3 radical has a large potential to contribute to SOA. We classified isoprene nitrates into generations and proposed formation pathways. Considering the potential functionalization of the isoprene nitrates we propose that mainly isoprene dimers contribute to SOA formation from the isoprene NO3 reactions with at least a 5 % mass yield.
This article is included in the Encyclopedia of Geosciences
Tommaso Galeazzo, Richard Valorso, Ying Li, Marie Camredon, Bernard Aumont, and Manabu Shiraiwa
Atmos. Chem. Phys., 21, 10199–10213, https://doi.org/10.5194/acp-21-10199-2021, https://doi.org/10.5194/acp-21-10199-2021, 2021
Short summary
Short summary
We simulate SOA viscosity with explicit modeling of gas-phase oxidation of isoprene and α-pinene. While the viscosity dependence on relative humidity and mass loadings is captured well by simulations, the model underestimates measured viscosity, indicating missing processes. Kinetic limitations and reduction in mass accommodation may cause an increase in viscosity. The developed model is powerful for investigation of the interplay among gas reactions, chemical composition and phase state.
This article is included in the Encyclopedia of Geosciences
Defeng Zhao, Iida Pullinen, Hendrik Fuchs, Stephanie Schrade, Rongrong Wu, Ismail-Hakki Acir, Ralf Tillmann, Franz Rohrer, Jürgen Wildt, Yindong Guo, Astrid Kiendler-Scharr, Andreas Wahner, Sungah Kang, Luc Vereecken, and Thomas F. Mentel
Atmos. Chem. Phys., 21, 9681–9704, https://doi.org/10.5194/acp-21-9681-2021, https://doi.org/10.5194/acp-21-9681-2021, 2021
Short summary
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The reaction of isoprene, a biogenic volatile organic compound with the globally largest emission rates, with NO3, an nighttime oxidant influenced heavily by anthropogenic emissions, forms a large number of highly oxygenated organic molecules (HOM). These HOM are formed via one or multiple oxidation steps, followed by autoxidation. Their total yield is much higher than that in the daytime oxidation of isoprene. They may play an important role in nighttime organic aerosol formation and growth.
This article is included in the Encyclopedia of Geosciences
Gabriel Isaacman-VanWertz and Bernard Aumont
Atmos. Chem. Phys., 21, 6541–6563, https://doi.org/10.5194/acp-21-6541-2021, https://doi.org/10.5194/acp-21-6541-2021, 2021
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Short summary
There are tens of thousands of different chemical compounds in the atmosphere. To tackle this complexity, there are a wide range of different methods to estimate their physical and chemical properties. We use these methods to understand how much the detailed structure of a molecule impacts its properties, and the extent to which properties can be estimated without knowing this level of detail. We find that structure matters, but methods lacking that level of detail still perform reasonably well.
This article is included in the Encyclopedia of Geosciences
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Editorial statement
This paper is written by experts in the field and addresses new tropospheric chemical mechanism developments. It shows how new analytical methods, instrumentation and cheminformatics methods have led to the identification of key processes and knowledge gaps in our understanding of chemical mechanisms, both in the gas phase and condensed phases. The opinion paper presents a perspective on these developments in the present and future, and outlines new directions. This opinion will be a very valuable contribution for the community and I am convinced it will be frequently read and cited.
This paper is written by experts in the field and addresses new tropospheric chemical mechanism...
Short summary
Chemical mechanisms describe the chemical processes in atmospheric models that are used to describe the changes in the atmospheric composition. Therefore, accurate chemical mechanisms are necessary to predict the evolution of air pollution and climate change. The article describes all steps that are needed to build chemical mechanisms and discusses the advances and needs of experimental and theoretical research activities needed to build reliable chemical mechanisms.
Chemical mechanisms describe the chemical processes in atmospheric models that are used to...
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