Articles | Volume 20, issue 5
Research article 12 Mar 2020
Research article | 12 Mar 2020
A predictive group-contribution model for the viscosity of aqueous organic aerosol
Natalie R. Gervasi et al.
No articles found.
Langwen Huang and David Topping
Geosci. Model Dev., 14, 2187–2203,Short summary
As our knowledge and understanding of atmospheric aerosol particle evolution and impact grows, designing community mechanistic models requires an ability to capture increasing chemical, physical and therefore numerical complexity. As the landscape of computing software and hardware evolves, it is important to profile the usefulness of emerging platforms in tackling this complexity. With this in mind we present JlBox v1.1, written in Julia.
Dalrin Ampritta Amaladhasan, Claudia Heyn, Christopher R. Hoyle, Imad El Haddad, Miriam Elser, Simone M. Pieber, Jay G. Slowik, Antonio Amorim, Jonathan Duplissy, Sebastian Ehrhart, Vladimir Makhmutov, Ugo Molteni, Matti Rissanen, Yuri Stozhkov, Robert Wagner, Armin Hansel, Jasper Kirkby, Neil M. Donahue, Rainer Volkamer, Urs Baltensperger, Martin Gysel-Beer, and Andreas Zuend
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
We employ a combination of models for gas-phase chemical reactions and equilibrium gas-particle partitioning of isoprene-derived secondary organic aerosols (SOA) informed by dark ozonolysis experiments conducted in the CLOUD chamber. Our predictions cover high to low relative humidities (RH) and quantify how SOA mass yields are enhanced at high RH as well as the impact of inorganic seeds of distinct hygroscopicities and acidities on the coupled partitioning of water and semivolatile organics.
Young-Chul Song, Joseph Lilek, Jae Bong Lee, Man Nin Chan, Zhijun Wu, Andreas Zuend, and Mijung Song
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We report viscosity of binary mixtures of organic material/H2O and inorganic salts/H2O, as well as ternary mixtures of organic material/inorganic salts/H2O over the atmospheric relative humidity (RH) range. The viscosity measurements indicate that the studied mixed organic–inorganic particles range in phase state from liquid to semi-solid or even solid across the atmospheric RH range at a temperature of 293 K.
Weigang Wang, Ting Lei, Andreas Zuend, Hang Su, Yafang Cheng, Yajun Shi, Maofa Ge, and Mingyuan Liu
Atmos. Chem. Phys., 21, 2179–2190,Short summary
Aerosol mixing state regulates the interactions between water molecules and particles and thus controls aerosol activation and hygroscopic growth, which thereby influences visibility degradation, cloud formation, and its radiative forcing. However, there are few studies attempting to investigate their interactions with water molecules. Here, we investigated the effect of organic coatings on the hygroscopic behavior of the inorganic core.
Hoi Ki Lam, Rongshuang Xu, Jack Choczynski, James F. Davies, Dongwan Ham, Mijung Song, Andreas Zuend, Wentao Li, Ying-Lung Steve Tse, and Man Nin Chan
Atmos. Chem. Phys., 21, 2053–2066,Short summary
This work demonstrates that organic compounds present at or near the surface of aerosols can be subjected to oxidation initiated by gas-phase oxidants, such as hydroxyl radicals (OH). The heterogeneous reactivity is sensitive to their surface concentrations, which are determined by the phase separation behavior. This results of this work emphasize the effects of phase separation and potentially distinct aerosol morphologies on the chemical transformation of atmospheric aerosols.
Simon Patrick O'Meara, Shuxuan Xu, David Topping, M. Rami Alfarra, Gerard Capes, Douglas Lowe, Yunqi Shao, and Gordon McFiggans
Geosci. Model Dev., 14, 675–702,Short summary
User-friendly and open-source software for simulating aerosol chambers is a valuable tool for research scientists in designing and analysing their experiments. This paper describes a new version of such software and will therefore provide a useful reference for those applying it. Central to the paper is an assessment of the software's accuracy through comparison against previously published simulations.
Douglas Morrison, Ian Crawford, Nicholas Marsden, Michael Flynn, Katie Read, Luis Neves, Virginia Foot, Paul Kaye, Warren Stanley, Hugh Coe, David Topping, and Martin Gallagher
Atmos. Chem. Phys., 20, 14473–14490,Short summary
We provide conservative estimates of the concentrations of bacteria within transatlantic dust clouds, originating from the African continent. We observe significant seasonal differences in the overall concentrations of particles but no seasonal variation in the ratio between bacteria and dust. With bacteria contributing to ice formation at warmer temperatures than dust, our observations should improve the accuracy of climate models.
David Topping, David Watts, Hugh Coe, James Evans, Thomas J. Bannan, Douglas Lowe, Caroline Jay, and Jonathan W. Taylor
Geosci. Model Dev. Discuss.,
Revised manuscript has not been submittedShort summary
Time-series forecasting methods have often been used to mitigate some of the challenges associated with deploying chemical transport models. In this study we deploy and evaluate Facebook’s Prophetmodel v0.6 in predicting hourly concentrations of Nitrogen Dioxide [NO2]. et. Overall we find the Prophet model offers a relatively effective and simple way to make predictions about NO2 at local levels.
Petroc D. Shelley, Thomas J. Bannan, Stephen D. Worrall, M. Rami Alfarra, Ulrich K. Krieger, Carl J. Percival, Arthur Garforth, and David Topping
Atmos. Chem. Phys., 20, 8293–8314,Short summary
The methods used to estimate the vapour pressures of compounds in the atmosphere typically perform poorly when applied to organic compounds found in the atmosphere. New measurements have been made and compared to previous experimental data and estimated values so that the limitations within the estimation methods can be identified and in the future be rectified.
Havala O. T. Pye, Athanasios Nenes, Becky Alexander, Andrew P. Ault, Mary C. Barth, Simon L. Clegg, Jeffrey L. Collett Jr., Kathleen M. Fahey, Christopher J. Hennigan, Hartmut Herrmann, Maria Kanakidou, James T. Kelly, I-Ting Ku, V. Faye McNeill, Nicole Riemer, Thomas Schaefer, Guoliang Shi, Andreas Tilgner, John T. Walker, Tao Wang, Rodney Weber, Jia Xing, Rahul A. Zaveri, and Andreas Zuend
Atmos. Chem. Phys., 20, 4809–4888,Short summary
Acid rain is recognized for its impacts on human health and ecosystems, and programs to mitigate these effects have had implications for atmospheric acidity. Historical measurements indicate that cloud and fog droplet acidity has changed in recent decades in response to controls on emissions from human activity, while the limited trend data for suspended particles indicate acidity may be relatively constant. This review synthesizes knowledge on the acidity of atmospheric particles and clouds.
Parya Broomandi, Xueyu Geng, Weisi Guo, Jong Ryeol Kim, Alessio Pagani, and David Topping
Geosci. Model Dev. Discuss.,
Revised manuscript not acceptedShort summary
As a result of our novel graph-based reduced modeling, we are able to represent high-dimensional knowledge into a causal inference and stability framework.
Kathryn Fowler, Paul Connolly, and David Topping
Atmos. Chem. Phys., 20, 683–698,Short summary
Observations of low–temperature cirrus clouds have found unexpectedly low ice crystal numbers and high supersaturations, suggesting an incomplete understanding of the freezing mechanisms under these conditions. The existence of viscous organic aerosol has offered alternative ice nucleation pathways, which have been observed in laboratory studies. We have developed the first cloud parcel model to investigate the effect of viscosity on ice nucleation.
Kyle Gorkowski, Thomas C. Preston, and Andreas Zuend
Atmos. Chem. Phys., 19, 13383–13407,Short summary
We present the new Binary Activity Thermodynamics (BAT) model, which is a water-sensitive reduced-complexity organic aerosol thermodynamics model. It can use bulk properties like O : C, molar mass, and RH to predict organic activity coefficients and water uptake behavior. We show applications in RH-dependent organic co-condensation, liquid–liquid phase separation, and Kohler curve predictions, and we validate the BAT model against laboratory measurements.
Hoi Ki Lam, Sze Man Shum, James F. Davies, Mijung Song, Andreas Zuend, and Man Nin Chan
Atmos. Chem. Phys., 19, 9581–9593,Short summary
We show the presence of dissolved inorganic salts could reduce the overall heterogeneous reactivity of organic compounds with gas–phase OH radicals at the surface by lowering the surface concentration of organic compounds. Until recently, the kinetic parameters reported in the literature were mostly measured based on experiments with pure organic particles. The lifetime of organic compounds or chemical tracers against heterogeneous OH reaction in the atmosphere could be longer than expected.
James F. Davies, Andreas Zuend, and Kevin R. Wilson
Atmos. Chem. Phys., 19, 2933–2946,Short summary
The formation of cloud droplets involves the condensation of water onto preexisting particles in the atmosphere. The efficiency of this process depends on the nature of the particles, and recent work has shown that organic-rich particles may exhibit a suppressed surface tension that promotes the formation of cloud droplets. In this technical note, we discuss the mechanism for this and highlight the evolution of surface tension as the key factor in the extent of surface effects.
Thomas J. Bannan, Michael Le Breton, Michael Priestley, Stephen D. Worrall, Asan Bacak, Nicholas A. Marsden, Archit Mehra, Julia Hammes, Mattias Hallquist, M. Rami Alfarra, Ulrich K. Krieger, Jonathan P. Reid, John Jayne, Wade Robinson, Gordon McFiggans, Hugh Coe, Carl J. Percival, and Dave Topping
Atmos. Meas. Tech., 12, 1429–1439,Short summary
The Filter Inlet for Gases and AEROsols (FIGAERO) is an inlet designed to be coupled with a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) and provides simultaneous molecular information relating to both the gas- and particle-phase samples. This method has been used to extract vapour pressures of compounds whilst giving quantitative concentrations in the particle phase. Here we detail an ideal set of benchmark compounds for characterization of the FIGAERO.
Elizabeth Forde, Martin Gallagher, Virginia Foot, Roland Sarda-Esteve, Ian Crawford, Paul Kaye, Warren Stanley, and David Topping
Atmos. Chem. Phys., 19, 1665–1684,Short summary
The abundance and diversity of airborne biological particles in different environments remains poorly constrained. Measurements of such particles were conducted at four sites in the United Kingdom, using real-time fluorescence instrumentation. Using local land cover types, sources of suspected particle types were identified and compared. Most sites exhibited a wet-discharged fungal spore dominance, with the exception of one site, which was inferred to be influenced by a local dairy farm.
Simon Ruske, David O. Topping, Virginia E. Foot, Andrew P. Morse, and Martin W. Gallagher
Atmos. Meas. Tech., 11, 6203–6230,Short summary
Pollen, bacteria and fungal spores are common in the environment, can have very important implications for public health and may influence the weather. Biological sensors potentially could be used to monitor quantities of these types of particles. However, it is important to transform the measurements from these instruments into counts of these biological particles. The paper tests a variety of approaches for achieving this aim on data collected in a laboratory.
Dawei Hu, David Topping, and Gordon McFiggans
Atmos. Chem. Phys., 18, 14925–14937,Short summary
Co-condensation of inorganic or organic vapours on growing droplets could significantly enhance both CCN and cloud droplet number concentration, thereby influencing climate. Until now, there has been very few direct observational evidence of this process. We exposed involatile inorganic particles to a moist atmosphere containing a controlled amount of an organic semi-volatile vapour. We measured a much greater growth of the particles than if they had only been exposed to water vapour.
Michael Le Breton, Yujue Wang, Åsa M. Hallquist, Ravi Kant Pathak, Jing Zheng, Yudong Yang, Dongjie Shang, Marianne Glasius, Thomas J. Bannan, Qianyun Liu, Chak K. Chan, Carl J. Percival, Wenfei Zhu, Shengrong Lou, David Topping, Yuchen Wang, Jianzhen Yu, Keding Lu, Song Guo, Min Hu, and Mattias Hallquist
Atmos. Chem. Phys., 18, 10355–10371,Short summary
This paper utilizes a chemical ionisation mass spectrometer measuring gas and particle-phase organosulfates (OS) simultaneously during a field campaign in Beijing, China, and highlights how high time frequency online measurements enable a detailed analysis of dominant production mechanisms. We find that high aerosol acidity, organic precursor concentration and relative humidity promote the production of OS. The thermogram desorption reveals the potential for semi-volatile gas-phase OS.
Stefano Decesari, Simona Kovarich, Manuela Pavan, Arianna Bassan, Andrea Ciacci, and David Topping
Atmos. Chem. Phys., 18, 2329–2340,Short summary
Particulate matter (PM) chemical composition includes thousands of individual organic compounds that have never been tested for their toxicological potential. Computational (in silico) screenings represent a promising approach to identify new target compounds for more in-depth toxicological analyses. We provide here a proof-of-concept evaluation based on ca. 100 aerosol organic compounds. Reliable toxicological predictions were obtained for more than 80 % of them.
Kathryn Fowler, Paul J. Connolly, David O. Topping, and Simon O'Meara
Atmos. Chem. Phys., 18, 1629–1642,Short summary
This is the first time the Maxwell–Stefan framework has been applied to an atmospheric aerosol core–shell model and shows that there is a complex interplay between the viscous and solubility effects on aerosol composition. Understanding aerosol composition is essential to accurately model their interactions within atmospheric systems. We use simple binary systems to demonstrate how viscosity and solubility both play a role in affecting the rate of diffusion through aerosol particles.
Ting Lei, Andreas Zuend, Yafang Cheng, Hang Su, Weigang Wang, and Maofa Ge
Atmos. Chem. Phys., 18, 1045–1064,Short summary
Measurements and thermodynamic equilibrium predictions for organic–inorganic aerosols related to components from biomass burning emissions demonstrate a diversity of hygroscopic growth and shrinking behavior, which we observed using a hygroscopicity tandem differential mobility analyzer (HTDMA). Controlled laboratory experiments with single solutes and/or with mixed organic–inorganic systems of known phase state will be useful to constrain model parameters of thermodynamic equilibrium models.
Havala O. T. Pye, Andreas Zuend, Juliane L. Fry, Gabriel Isaacman-VanWertz, Shannon L. Capps, K. Wyat Appel, Hosein Foroutan, Lu Xu, Nga L. Ng, and Allen H. Goldstein
Atmos. Chem. Phys., 18, 357–370,Short summary
Thermodynamic modeling revealed that some but not all measurements of ammonium-to-sulfate ratios are consistent with theory. The measurement diversity likely explains the previously reported range of results regarding the suitability of thermodynamic modeling. Despite particles being predominantly phase separated, organic–inorganic interactions resulted in increased aerosol pH and partitioning towards the particle phase for highly oxygenated organic compounds compared to traditional methods.
Ulrich K. Krieger, Franziska Siegrist, Claudia Marcolli, Eva U. Emanuelsson, Freya M. Gøbel, Merete Bilde, Aleksandra Marsh, Jonathan P. Reid, Andrew J. Huisman, Ilona Riipinen, Noora Hyttinen, Nanna Myllys, Theo Kurtén, Thomas Bannan, Carl J. Percival, and David Topping
Atmos. Meas. Tech., 11, 49–63,Short summary
Vapor pressures of low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique, which is generally reported to be smaller than a factor of 2. We determined saturation vapor pressures for the homologous series of polyethylene glycols ranging in vapor pressure at 298 K from 1E−7 Pa to 5E−2 Pa as a reference set.
Man Mei Chim, Chiu Tung Cheng, James F. Davies, Thomas Berkemeier, Manabu Shiraiwa, Andreas Zuend, and Man Nin Chan
Atmos. Chem. Phys., 17, 14415–14431,Short summary
In this work, we report that methyl-substituted succinic acid present at or near the surface of aqueous organic droplets can be efficiently oxidized by gas-phase OH radicals. The alkoxy radical chemistry appears to be an important reaction pathway. In addition, our model simulations reveal the relative importance of functionalization and fragmentation processes, alongside volatilization, in the evolution of the particle-phase reaction, which is largely dependent on the extent of oxidation.
Simon O'Meara, David O. Topping, Rahul A. Zaveri, and Gordon McFiggans
Atmos. Chem. Phys., 17, 10477–10494,Short summary
To simulate particle-phase diffusion, an analytical expression is desired because it takes less calculation time than a differential equation. Here a correction is found for the analytical solution for when diffusivity is dependent on composition, thereby making it more widely applicable than before. Consequently, we are able to more realistically evaluate the rate limitation (if any) imposed by particle-phase diffusion on component partitioning between the gas and particle phase.
David O. Topping, James Allan, M. Rami Alfarra, and Bernard Aumont
Geosci. Model Dev., 10, 2365–2377,Short summary
Our ability to model the chemical and thermodynamic processes that lead to secondary organic aerosol (SOA) formation is thought to be hampered by the complexity of the system. In this proof of concept study, the ability to train supervised methods to predict electron impact ionisation (EI) mass spectra for the AMS is evaluated to facilitate improved model evaluation. The study demonstrates the use of a methodology that would be improved with more training data and data from simple mixed systems.
Simon Ruske, David O. Topping, Virginia E. Foot, Paul H. Kaye, Warren R. Stanley, Ian Crawford, Andrew P. Morse, and Martin W. Gallagher
Atmos. Meas. Tech., 10, 695–708,Short summary
Particles such as bacteria, pollen and fungal spores have important implications within the environment and public health sectors. Here we evaluate the performance of various different methods for distinguishing between these different types of particles using a new instrument. We demonstrate that there may be better alternatives to the currently used methods which can be further investigated in future research.
François Benduhn, Graham W. Mann, Kirsty J. Pringle, David O. Topping, Gordon McFiggans, and Kenneth S. Carslaw
Geosci. Model Dev., 9, 3875–3906,Short summary
We present a new mathematical formalism that serves to represent exchanges of inorganic matter between the atmosphere gas phase and the aerosol aqueous phase. In a global modelling framework, taking into account these processes may help represent many important features more accurately, such as the formation of cloud droplets or the radiative properties of the atmosphere. The formalism strives to keep an appropriate balance between accuracy and computation efficiency requirements.
Natasha Hodas, Andreas Zuend, Katherine Schilling, Thomas Berkemeier, Manabu Shiraiwa, Richard C. Flagan, and John H. Seinfeld
Atmos. Chem. Phys., 16, 12767–12792,Short summary
Discontinuities in apparent hygroscopicity below and above water saturation have been observed for organic and mixed organic-inorganic aerosol particles in both laboratory studies and in the ambient atmosphere. This work explores the extent to which such discontinuities are influenced by organic component molecular mass and viscosity, non-ideal thermodynamic interactions between aerosol components, and the combination of these factors.
Matthew Crooks, Paul Connolly, David Topping, and Gordon McFiggans
Geosci. Model Dev., 9, 3617–3637,Short summary
Semi-volatile compounds, like water, can exist in both vapour phases and condensed phases within a system. This paper presents a method of calculating the condensed and vapour phases of semi-volatile compounds at equilibrium, in particular, when the condensed mass occurs within particles of different sizes and chemical composition. The applications of interest to the authors are those of atmospheric importance such as cloud droplet formation and reflection or absorption of solar radiation.
Samuel Lowe, Daniel G. Partridge, David Topping, and Philip Stier
Atmos. Chem. Phys., 16, 10941–10963,Short summary
A novel inverse modelling framework is developed for analysing the sensitivity of cloud condensation nuclei (CCN) concentrations to simultaneous perturbations in multiple model parameters at atmospherically relevant humidities. Many parameter interactions are identified and CCN concentrations are found to be relatively insensitive to bulk–surface partitioning, while aerosol concentration, surface tension, composition and solution ideality exhibit a higher degree of sensitivity.
Simon O'Meara, David O. Topping, and Gordon McFiggans
Atmos. Chem. Phys., 16, 5299–5313,Short summary
To understand the effect of atmospheric particulate matter on climate and human health we need to know how it evolves. We investigate how best to estimate diffusion of components through particles by comparing diffusion times from three approaches to solving Fick's Law and find that they agree. This means that scientists can simulate Fickian diffusion through atmospheric particles using the approach best suited to their requirements and have confidence that their model is mathematically sound.
David Topping, Mark Barley, Michael K. Bane, Nicholas Higham, Bernard Aumont, Nicholas Dingle, and Gordon McFiggans
Geosci. Model Dev., 9, 899–914,Short summary
In this paper we describe the development and application of a new web-based and open-source facility, UManSysProp (http://umansysprop .seaes.manchester.ac.uk), for automating predictions of molecular and atmospheric aerosol properties. Current facilities include pure component vapour pressures, critical properties, and sub-cooled densities of organic molecules; activity coefficient predictions for mixed inorganic-organic liquid systems; hygroscopic growth factors and CCN activation potential.
I. Crawford, S. Ruske, D. O. Topping, and M. W. Gallagher
Atmos. Meas. Tech., 8, 4979–4991,Short summary
HCA analysis methods were evaluated for the purpose of identifying primary biological aerosol sampled with a WIBS. The ward linkage with z-score normalisation could discriminate between five test particles with 98% accuracy. We applied these methods to a previously studied ambient data set, where both methods produced similar results with some minor differences in cluster partitioning. Finally we compared to previous approaches and found our new method offered improved quantification of PBA.
N. Hodas, A. Zuend, W. Mui, R. C. Flagan, and J. H. Seinfeld
Atmos. Chem. Phys., 15, 5027–5045,
G. Ganbavale, A. Zuend, C. Marcolli, and T. Peter
Atmos. Chem. Phys., 15, 447–493,Short summary
This study presents a new, improved parameterisation of the temperature dependence of activity coefficients implemented in the AIOMFAC group-contribution model. The AIOMFAC model with the improved parameterisation is applicable for a large variety of aqueous organic as well as water-free organic solutions of relevance for atmospheric aerosols. The new model parameters were determined based on published and new thermodynamic equilibrium data covering a temperature range from ~190 to 440 K.
T. Lei, A. Zuend, W. G. Wang, Y. H. Zhang, and M. F. Ge
Atmos. Chem. Phys., 14, 11165–11183,
G. Ganbavale, C. Marcolli, U. K. Krieger, A. Zuend, G. Stratmann, and T. Peter
Atmos. Chem. Phys., 14, 9993–10012,
P. J. Connolly, D. O. Topping, F. Malavelle, and G. McFiggans
Atmos. Chem. Phys., 14, 2289–2302,
A. J. Huisman, U. K. Krieger, A. Zuend, C. Marcolli, and T. Peter
Atmos. Chem. Phys., 13, 6647–6662,
Related subject area
Subject: Aerosols | Research Activity: Atmospheric Modelling | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)Insights into seasonal variation of wet deposition over southeast Asia via precipitation adjustment from the findings of MICS-Asia IIIModeling the impact of COVID-19 on air quality in southern California: implications for future control policiesResponses of Arctic black carbon and surface temperature to multi-region emission reductions: a Hemispheric Transport of Air Pollution Phase 2 (HTAP2) ensemble modeling studyAnalysis of secondary organic aerosol simulation bias in the Community Earth System Model (CESM2.1)Future evolution of aerosols and implications for climate change in the Euro-Mediterranean region using the CNRM-ALADIN63 regional climate modelSource apportionment of fine organic carbon at an urban site of Beijing using a chemical mass balance modelModeled changes in source contributions of particulate matter during the 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A multi-model intercomparison study for MICS-Asia IIIEvaluating the impact of blowing-snow sea salt aerosol on springtime BrO and O3 in the ArcticImpacts of water partitioning and polarity of organic compounds on secondary organic aerosol over eastern ChinaMultiphase MCM–CAPRAM modeling of the formation and processing of secondary aerosol constituents observed during the Mt. Tai summer campaign in 2014
Syuichi Itahashi, Baozhu Ge, Keiichi Sato, Zhe Wang, Junichi Kurokawa, Jiani Tan, Kan Huang, Joshua S. Fu, Xuemei Wang, Kazuyo Yamaji, Tatsuya Nagashima, Jie Li, Mizuo Kajino, Gregory R. Carmichael, and Zifa Wang
Atmos. Chem. Phys., 21, 8709–8734,Short summary
This study presents the detailed analysis of acid deposition over southeast Asia based on the Model Inter-Comparison Study for Asia (MICS-Asia) phase III. Simulated wet deposition is evaluated with observation data from the Acid Deposition Monitoring Network in East Asia (EANET). The difficulties of models to capture observations are related to the model performance on precipitation. The precipitation-adjusted approach was applied, and the distribution of wet deposition was successfully revised.
Zhe Jiang, Hongrong Shi, Bin Zhao, Yu Gu, Yifang Zhu, Kazuyuki Miyazaki, Xin Lu, Yuqiang Zhang, Kevin W. Bowman, Takashi Sekiya, and Kuo-Nan Liou
Atmos. Chem. Phys., 21, 8693–8708,Short summary
We use the COVID-19 pandemic as a unique natural experiment to obtain a more robust understanding of the effectiveness of emission reductions toward air quality improvement by combining chemical transport simulations and observations. Our findings imply a shift from current control policies in California: a strengthened control on primary PM2.5 emissions and a well-balanced control on NOx and volatile organic compounds are needed to effectively and sustainably alleviate PM2.5 and O3 pollution.
Na Zhao, Xinyi Dong, Kan Huang, Joshua S. Fu, Marianne Tronstad Lund, Kengo Sudo, Daven Henze, Tom Kucsera, Yun Fat Lam, Mian Chin, and Simone Tilmes
Atmos. Chem. Phys., 21, 8637–8654,Short summary
Black carbon acts as a strong climate forcer, especially in vulnerable pristine regions such as the Arctic. This work utilizes ensemble modeling results from the task force Hemispheric Transport of Air Pollution Phase 2 to investigate the responses of Arctic black carbon and surface temperature to various source emission reductions. East Asia contributed the most to Arctic black carbon. The response of Arctic temperature to black carbon was substantially more sensitive than the global average.
Yaman Liu, Xinyi Dong, Minghuai Wang, Louisa K. Emmons, Yawen Liu, Yuan Liang, Xiao Li, and Manish Shrivastava
Atmos. Chem. Phys., 21, 8003–8021,Short summary
Secondary organic aerosol (SOA) is considered one of the most important uncertainties in climate modeling. We evaluate SOA performance in the Community Earth System Model version 2.1 (CESM2.1) configured with the Community Atmosphere Model version 6 with chemistry (CAM6-Chem) through a long-term simulation (1988–2019) with observations in the United States, which indicates monoterpene-formed SOA contributes most to the overestimation of SOA at the surface and underestimation in the upper air.
Thomas Drugé, Pierre Nabat, Marc Mallet, and Samuel Somot
Atmos. Chem. Phys., 21, 7639–7669,Short summary
This study presents the surface mass concentration and AOD evolution of various aerosols over the Euro-Mediterranean region between the end of the 20th century and the mid-21st century. This study also describes the part of the expected climate change over the Euro-Mediterranean region that can be explained by the evolution of these different aerosols.
Jingsha Xu, Di Liu, Xuefang Wu, Tuan V. Vu, Yanli Zhang, Pingqing Fu, Yele Sun, Weiqi Xu, Bo Zheng, Roy M. Harrison, and Zongbo Shi
Atmos. Chem. Phys., 21, 7321–7341,Short summary
Source apportionment of fine aerosols in an urban site of Beijing used a chemical mass balance (CMB) model. Seven primary sources (industrial/residential coal burning, biomass burning, gasoline/diesel vehicles, cooking and vegetative detritus) explained an average of 75.7 % and 56.1 % of fine OC in winter and summer, respectively. CMB was found to resolve more primary OA sources than AMS-PMF, but the latter apportioned more secondary OA sources.
Jinlong Ma, Juanyong Shen, Peng Wang, Shengqiang Zhu, Yu Wang, Pengfei Wang, Gehui Wang, Jianmin Chen, and Hongliang Zhang
Atmos. Chem. Phys., 21, 7343–7355,Short summary
Due to the reduced anthropogenic emissions during the COVID-19 lockdown, mainly from the transportation and industrial sectors, PM2.5 decreased significantly in the whole Yangtze River Delta (YRD) and its major cities. However, the contributions and relative importance of different source sectors and regions changed differently, indicating that control strategies should be adjusted accordingly for further pollution control.
Janaína P. Nascimento, Megan M. Bela, Bruno B. Meller, Alessandro L. Banducci, Luciana V. Rizzo, Angel Liduvino Vara-Vela, Henrique M. J. Barbosa, Helber Gomes, Sameh A. A. Rafee, Marco A. Franco, Samara Carbone, Glauber G. Cirino, Rodrigo A. F. Souza, Stuart A. McKeen, and Paulo Artaxo
Atmos. Chem. Phys., 21, 6755–6779,
Mingxu Liu and Hitoshi Matsui
Atmos. Chem. Phys., 21, 5965–5982,Short summary
By integrating an advanced global climate model with the latest anthropogenic emission inventory, we quantify the aerosol perturbations to regional radiative budgets due to the changes in anthropogenic emissions in China from 2008–2016. We find that aerosol–radiation interactions lead to a relatively small net radiative forcing at the top of the atmosphere but contribute largely to surface brightening in China over the past few decades.
Yawei Qu, Apostolos Voulgarakis, Tijian Wang, Matthew Kasoar, Chris Wells, Cheng Yuan, Sunil Varma, and Laura Mansfield
Atmos. Chem. Phys., 21, 5705–5718,Short summary
The meteorological effect of aerosols on tropospheric ozone is investigated using global atmospheric modelling. We found that aerosol-induced meteorological effects act to reduce modelled ozone concentrations over China, which brings the simulation closer to observed levels. Our work sheds light on understudied processes affecting the levels of tropospheric gaseous pollutants and provides a basis for evaluating such processes using a combination of observations and model sensitivity experiments.
Minghui Zhang, Amina Khaled, Pierre Amato, Anne-Marie Delort, and Barbara Ervens
Atmos. Chem. Phys., 21, 3699–3724,Short summary
Although primary biological aerosol particles (PBAPs, bioaerosols) represent a small fraction of total atmospheric aerosol burden, they might affect climate and public health. We summarize which PBAP properties are important to affect their inclusion in clouds and interaction with light and might also affect their residence time and transport in the atmosphere. Our study highlights that not only chemical and physical but also biological processes can modify these physicochemical properties.
Duseong S. Jo, Alma Hodzic, Louisa K. Emmons, Simone Tilmes, Rebecca H. Schwantes, Michael J. Mills, Pedro Campuzano-Jost, Weiwei Hu, Rahul A. Zaveri, Richard C. Easter, Balwinder Singh, Zheng Lu, Christiane Schulz, Johannes Schneider, John E. Shilling, Armin Wisthaler, and Jose L. Jimenez
Atmos. Chem. Phys., 21, 3395–3425,Short summary
Secondary organic aerosol (SOA) is a major component of submicron particulate matter, but there are a lot of uncertainties in the future prediction of SOA. We used CESM 2.1 to investigate future IEPOX SOA concentration changes. The explicit chemistry predicted substantial changes in IEPOX SOA depending on the future scenario, but the parameterization predicted weak changes due to simplified chemistry, which shows the importance of correct physicochemical dependencies in future SOA prediction.
Behrooz Roozitalab, Gregory R. Carmichael, and Sarath K. Guttikunda
Atmos. Chem. Phys., 21, 2837–2860,Short summary
We used air quality modeling to study an extreme pollution episode in November 2017 in India. We found both local and regional emissions contribute to high pollution levels. The extreme pollution values were the result of agricultural fires in the northwest of India. Ozone should be considered in future air quality management strategies.
Ling Huang, Yonghui Zhu, Hehe Zhai, Shuhui Xue, Tianyi Zhu, Yun Shao, Ziyi Liu, Chris Emery, Greg Yarwood, Yangjun Wang, Joshua Fu, Kun Zhang, and Li Li
Atmos. Chem. Phys., 21, 2725–2743,Short summary
Numerical air quality models (AQMs) are being applied extensively to address diverse scientific and regulatory compliance associated with deteriorating air quality in China. For any AQM applications, model performance evaluation is a critical step that guarantees the robustness and reliability of the baseline modeling results and subsequent applications. We provided benchmarks for model performance evaluation of AQM applications in China to demonstrate model robustness.
Adriana Bossolasco, Fabrice Jegou, Pasquale Sellitto, Gwenaël Berthet, Corinna Kloss, and Bernard Legras
Atmos. Chem. Phys., 21, 2745–2764,Short summary
Using the Community Earth System Model, we simulate the surface aerosols lifted to the Asian tropopause (the ATAL layer), its composition and trend, covering a long-term period (2000–2015). We identify a
double-peakaerosol vertical profile that we attribute to
convectivecloud-borne aerosols. We find that natural aerosol (mineral dust) is the dominant aerosol type and has no long-term trend. ATAL's anthropogenic fraction, by contrast, shows a marked positive trend.
Youhua Tang, Huisheng Bian, Zhining Tao, Luke D. Oman, Daniel Tong, Pius Lee, Patrick C. Campbell, Barry Baker, Cheng-Hsuan Lu, Li Pan, Jun Wang, Jeffery McQueen, and Ivanka Stajner
Atmos. Chem. Phys., 21, 2527–2550,Short summary
Chemical lateral boundary condition (CLBC) impact is essential for regional air quality prediction during intrusion events. We present a model mapping Goddard Earth Observing System (GEOS) to Community Multi-scale Air Quality (CMAQ) CB05–AERO6 (Carbon Bond 5; version 6 of the aerosol module) species. Influence depends on distance from the inflow boundary and species and their regional characteristics. We use aerosol optical thickness to derive CLBCs, achieving reasonable prediction.
Robin Wollesen de Jonge, Jonas Elm, Bernadette Rosati, Sigurd Christiansen, Noora Hyttinen, Dana Lüdemann, Merete Bilde, and Pontus Roldin
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
This study presents a detailed analysis of the OH-initiated oxidation of dimethyl sulfide (DMS) based on experiments performed in the Aarhus University research on aerosols (AURA) smog chamber and the gas- and particle-phase chemistry kinetic multilayer model (ADCHAM). We capture the formation, growth and chemical composition of aerosols in the chamber setup by an improved multiphase oxidation mechanism, and utilize our results to reproduce the important role of DMS in the marine boundary layer.
Tommaso Galeazzo, Richard Valorso, Ying Li, Marie Camredon, Bernard Aumont, and Manabu Shiraiwa
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort 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 of viscosity. The developed model is powerful for investigation of the interplay among gas reactions, chemical composition and phase state.
Philippe Thunis, Alain Clappier, Matthias Beekmann, Jean Philippe Putaud, Cornelis Cuvelier, Jessie Madrazo, and Alexander de Meij
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
In this work, we use modelling simulations to identify the most efficient emission reduction strategies to reduce PM2.5 concentration levels in Northern Italy. Results show contrasting chemical regimes and important non-linearities during wintertime, with the striking result that PM2.5 levels may increase when NOx reductions are applied in NOx-rich areas. A process that may have contributed to the absence of significant PM2.5 decrease during the COVID-19 lockdowns in many European cities.
Gillian Thornhill, William Collins, Dirk Olivié, Ragnhild B. Skeie, Alex Archibald, Susanne Bauer, Ramiro Checa-Garcia, Stephanie Fiedler, Gerd Folberth, Ada Gjermundsen, Larry Horowitz, Jean-Francois Lamarque, Martine Michou, Jane Mulcahy, Pierre Nabat, Vaishali Naik, Fiona M. O'Connor, Fabien Paulot, Michael Schulz, Catherine E. Scott, Roland Séférian, Chris Smith, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, and James Weber
Atmos. Chem. Phys., 21, 1105–1126,Short summary
We find that increased temperatures affect aerosols and reactive gases by changing natural emissions and their rates of removal from the atmosphere. Changing the composition of these species in the atmosphere affects the radiative budget of the climate system and therefore amplifies or dampens the climate response of climate models of the Earth system. This study found that the largest effect is a dampening of climate change as warmer temperatures increase the emissions of cooling aerosols.
Stylianos Kakavas, David Patoulias, Maria Zakoura, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 799–811,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.
Igor B. Konovalov, Nikolai A. Golovushkin, Matthias Beekmann, and Meinrat O. Andreae
Atmos. Chem. Phys., 21, 357–392,Short summary
A lack of consistent observational constraints on the atmospheric evolution of the optical properties of biomass burning (BB) aerosol limits the accuracy of assessments of the aerosol radiative and climate effects. We show that useful insights into the evolution of the BB aerosol optical properties can be inferred from a combination of satellite observations and 3D modeling. We report major changes that occurred in the optical properties of Siberian BB aerosol during its long-range transport.
Shaojie Song, Tao Ma, Yuzhong Zhang, Lu Shen, Pengfei Liu, Ke Li, Shixian Zhai, Haotian Zheng, Meng Gao, Jonathan M. Moch, Fengkui Duan, Kebin He, and Michael B. McElroy
Atmos. Chem. Phys., 21, 457–481,Short summary
We simulate the atmospheric chemical processes of an important sulfur-containing organic aerosol species, which is produced by the reaction between sulfur dioxide and formaldehyde. We can predict its distribution on a global scale. We find it is particularly rich in East Asia. This aerosol species is more abundant in the colder season partly because of weaker sunlight.
Liqiang Wang, Shaocai Yu, Pengfei Li, Xue Chen, Zhen Li, Yibo Zhang, Mengying Li, Khalid Mehmood, Weiping Liu, Tianfeng Chai, Yannian Zhu, Daniel Rosenfeld, and John H. Seinfeld
Atmos. Chem. Phys., 20, 14787–14800,Short summary
The Chinese government has made major strides in curbing anthropogenic emissions. In this study, we constrain a state-of-the-art CTM by a reliable data assimilation method with extensive chemical and meteorological observations. This comprehensive technical design provides a crucial advance in isolating the influences of emission changes and meteorological perturbations over the Yangtze River Delta (YRD) from 2016 to 2019, thus establishing the first map of the PM2.5 mitigation across the YRD.
Steven T. Turnock, Robert J. Allen, Martin Andrews, Susanne E. Bauer, Makoto Deushi, Louisa Emmons, Peter Good, Larry Horowitz, Jasmin G. John, Martine Michou, Pierre Nabat, Vaishali Naik, David Neubauer, Fiona M. O'Connor, Dirk Olivié, Naga Oshima, Michael Schulz, Alistair Sellar, Sungbo Shim, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, Tongwen Wu, and Jie Zhang
Atmos. Chem. Phys., 20, 14547–14579,Short summary
A first assessment is made of the historical and future changes in air pollutants from models participating in the 6th Coupled Model Intercomparison Project (CMIP6). Substantial benefits to future air quality can be achieved in future scenarios that implement measures to mitigate climate and involve reductions in air pollutant emissions, particularly methane. However, important differences are shown between models in the future regional projection of air pollutants under the same scenario.
Huiying Luo, Marina Astitha, Christian Hogrefe, Rohit Mathur, and S. Trivikrama Rao
Atmos. Chem. Phys., 20, 13801–13815,Short summary
A new method is introduced to evaluate nonlinear, nonstationary modeled PM2.5 time series by decomposing decadal PM2.5 concentrations and its species onto various timescales. It does not require preselection of temporal scales and assumptions of linearity and stationarity. It provides a unique opportunity to assess the influence of each species on total PM2.5. The results reveal a phase shift in modeled EC/OC concentrations, indicating the need for improved model treatment of organic aerosols.
Yiqi Zheng, Joel A. Thornton, Nga Lee Ng, Hansen Cao, Daven K. Henze, Erin E. McDuffie, Weiwei Hu, Jose L. Jimenez, Eloise A. Marais, Eric Edgerton, and Jingqiu Mao
Atmos. Chem. Phys., 20, 13091–13107,Short summary
This study aims to address a challenge in biosphere–atmosphere interactions: to what extent can biogenic organic aerosol (OA) be modified through human activities? From three surface network observations, we show OA is weakly dependent on sulfate and aerosol acidity in the summer southeast US, on both long-term trends and monthly variability. The results are in strong contrast to a global model, GEOS-Chem, suggesting the need to revisit the representation of aqueous-phase secondary OA formation.
Ruqian Miao, Qi Chen, Yan Zheng, Xi Cheng, Yele Sun, Paul I. Palmer, Manish Shrivastava, Jianping Guo, Qiang Zhang, Yuhan Liu, Zhaofeng Tan, Xuefei Ma, Shiyi Chen, Limin Zeng, Keding Lu, and Yuanhang Zhang
Atmos. Chem. Phys., 20, 12265–12284,Short summary
In this study we evaluated the model performances for simulating secondary inorganic aerosol (SIA) and organic aerosol (OA) in PM2.5 in China against comprehensive datasets. The potential biases from factors related to meteorology, emission, chemistry, and atmospheric removal are systematically investigated. This study provides a comprehensive understanding of modeling PM2.5, which is important for studies on the effectiveness of emission control strategies.
Wei Tao, Hang Su, Guangjie Zheng, Jiandong Wang, Chao Wei, Lixia Liu, Nan Ma, Meng Li, Qiang Zhang, Ulrich Pöschl, and Yafang Cheng
Atmos. Chem. Phys., 20, 11729–11746,Short summary
We simulated the thermodynamic and multiphase reactions in aerosol water during a wintertime haze event over the North China Plain. It was found that aerosol pH exhibited a strong spatiotemporal variability, and multiple oxidation pathways were predominant for particulate sulfate formation in different locations. Sensitivity tests further showed that ammonia, crustal particles, and dissolved transition metal ions were important factors for multiphase chemistry during haze episodes.
Ben Silver, Luke Conibear, Carly L. Reddington, Christoph Knote, Steve R. Arnold, and Dominick V. Spracklen
Atmos. Chem. Phys., 20, 11683–11695,Short summary
China suffers from serious air pollution, which is thought to cause millions of early deaths each year. Measurements on the ground show that overall air quality is improving. Air quality is also affected by weather conditions, which can vary from year to year. We conduct computer simulations to show it is the reduction of the amount of pollution emitted, rather than weather conditions, which caused air quality to improve during 2015–2017. We then estimate that 150 000 fewer people die early.
Paul A. Makar, Ayodeji Akingunola, Jack Chen, Balbir Pabla, Wanmin Gong, Craig Stroud, Christopher Sioris, Kerry Anderson, Philip Cheung, Junhua Zhang, and Jason Milbrandt
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We have examined the effects of airborne particles on absorption and scattering of incoming sunlight by the particles themselves via cloud formation. We used an advanced, combined high-resolution weather forecast and chemical transport computer model, for western North America, and simulations with/without the connections between particles and weather enabled. Feedbacks improved weather and air pollution forecasts, and changed cloud behaviour and forest fire pollutant amount and height.
Jan Eiof Jonson, Michael Gauss, Michael Schulz, Jukka-Pekka Jalkanen, and Hilde Fagerli
Atmos. Chem. Phys., 20, 11399–11422,Short summary
We have calculated the effects of air pollution in Europe from shipping on levels of PM2.5 and ozone and depositions of oxidised nitrogen and sulfur from individual sea areas and from all global shipping. Model results are shown for Europe as a whole but also focusing on select, mainly coastal, countries. Calculations are made using 2017 emissions supplemented by calculations reducing sulfur emissions from ships by about 80 % following the implementation of the 2020 global sulfur cap.
Isaac Kwadjo Afreh, Bernard Aumont, Marie Camredon, and Kelley Claire Barsanti
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
This is the first SOA modeling study of the ubiquitous but understudied monoterpene, camphene. The explicit chemical model GECKO-A represented chamber data for two well-studied monoterpenes. The predicted camphene SOA yield was relatively high in comparison, ~2× 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.
Ahmad Jhony Rusumdar, Andreas Tilgner, Ralf Wolke, and Hartmut Herrmann
Atmos. Chem. Phys., 20, 10351–10377,Short summary
In the present study, simulations with the SPACCIM-SpactMod multiphase chemistry model are performed. The investigations aim at assessing the impact of a detailed treatment of non-ideality in multiphase models dealing with aqueous aerosol chemistry. The model studies demonstrate that the inclusion of non-ideality considerably affects the multiphase chemical processing of transition metal ions, oxidants, and related chemical subsystems such as organic chemistry in aqueous aerosols.
Hyun Cheol Kim, Tianfeng Chai, Ariel Stein, and Shobha Kondragunta
Atmos. Chem. Phys., 20, 10259–10277,Short summary
Smoke forecasts have been challenged by high uncertainty in fire emission estimates. We develop an inverse modeling system, the HYSPLIT-based Emissions Inverse Modeling System for wildfires, that estimates wildfire emissions from the transport and dispersion of smoke plumes as measured by satellite observations. Using NOAA HYSPLIT and GOES Aerosol/Smoke Product (GASP), the system resolves smoke source strength as a function of time and vertical level and outperforms current operational system.
Satoru Chatani, Hikari Shimadera, Syuichi Itahashi, and Kazuyo Yamaji
Atmos. Chem. Phys., 20, 10311–10329,Short summary
Source sensitivities and apportionments of PM2.5 and ozone concentrations over Japan for 2016 were evaluated using multiple numerical techniques including BFM, HDDM, and ISAM, embedded in regional chemical transport models. Influences of stringent emission controls recently implemented in Asian countries were reflected. Differences between sensitivities and apportionments greatly helped distinguish various direct and indirect effects of emission sources on PM2.5 and ozone concentrations.
Xiao Han, Lingyun Zhu, Mingxu Liu, Yu Song, and Meigen Zhang
Atmos. Chem. Phys., 20, 9979–9996,Short summary
China is one of the largest agricultural countries in the world. Some of the major PM2.5 particles that cause the atmospheric haze and impact the climate change were converted from agricultural NH3 emission. This paper applied the numerical modeling system, coupled with a high-resolution agricultural NH3 emissions inventory, to investigate the contribution of agricultural NH3 to PM2.5 mass burden in China and obtained some interesting results.
Robert J. Allen, Steven Turnock, Pierre Nabat, David Neubauer, Ulrike Lohmann, Dirk Olivié, Naga Oshima, Martine Michou, Tongwen Wu, Jie Zhang, Toshihiko Takemura, Michael Schulz, Kostas Tsigaridis, Susanne E. Bauer, Louisa Emmons, Larry Horowitz, Vaishali Naik, Twan van Noije, Tommi Bergman, Jean-Francois Lamarque, Prodromos Zanis, Ina Tegen, Daniel M. Westervelt, Philippe Le Sager, Peter Good, Sungbo Shim, Fiona O'Connor, Dimitris Akritidis, Aristeidis K. Georgoulias, Makoto Deushi, Lori T. Sentman, Jasmin G. John, Shinichiro Fujimori, and William J. Collins
Atmos. Chem. Phys., 20, 9641–9663,
Hyun Cheol Kim, Soontae Kim, Mark Cohen, Changhan Bae, Dasom Lee, Rick Saylor, Minah Bae, Eunhye Kim, Byeong-Uk Kim, Jin-Ho Yoon, and Ariel Stein
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Global outbreaks of COVID-19 offer rare opportunities of natural experiments in emission control and corresponding responses of tropospheric chemistry. This study's novel approach investigates (1) isolating pandemic's impact from natural and anthropogenic variations, (2) emission-adjustment to reproduce real-time emissions (3) brute-force modeling to investigate Chinese economic activities. Results provide characteristics of the region's chemistry and emissions.
Rafael A. O. Nunes, Maria C. M. Alvim-Ferraz, Fernando G. Martins, Fátima Calderay-Cayetano, Vanessa Durán-Grados, Juan Moreno-Gutiérrez, Jukka-Pekka Jalkanen, Hanna Hannuniemi, and Sofia I. V. Sousa
Atmos. Chem. Phys., 20, 9473–9489,Short summary
The central position of the Iberian Peninsula with ship traffic between the Americas, Africa, and Europe, combined with the known adverse effects of this sector on air quality, emphasises the relevance of a more detailed study of these impacts in this region. Results showed increased levels of SO2 and NO2 near port areas, as well as of O3, sulfate, PM2.5, and PM10 over the Iberian Peninsula coastline due to shipping emissions. To study mitigation measures, application is crucial.
Jaakko Kukkonen, Mikko Savolahti, Yuliia Palamarchuk, Timo Lanki, Väinö Nurmi, Ville-Veikko Paunu, Leena Kangas, Mikhail Sofiev, Ari Karppinen, Androniki Maragkidou, Pekka Tiittanen, and Niko Karvosenoja
Atmos. Chem. Phys., 20, 9371–9391,Short summary
We have developed a mathematical model that can be used to analyse the benefits that could be achieved by implementing alternative air quality abatement measures, policies or strategies. The model was applied to determine pollution sources in the whole of Finland in 2015. Clearly the most economically effective measures were the reduction in emissions from low-level sources in urban areas. Such sources include road transport, non-road vehicles and machinery, and residential wood combustion.
Wei Sun, Zhiquan Liu, Dan Chen, Pusheng Zhao, and Min Chen
Atmos. Chem. Phys., 20, 9311–9329,Short summary
A new aerosol and gas pollutant assimilation capability is developed within the WRFDA system with the 3D variational algorithm and MOSAIC (Model for Simulating Aerosol Interactions and Chemistry) aerosol scheme. By assimilating surface PM2.5, PM10, SO2, NO2, O3, and CO, it improves 24 h air quality forecasting. Based on this system, model deficiencies are explored. Parameterization in the newly added inorganic aerosol heterogeneous reactions should be adjusted and verified by data assimilation.
Alexander Ukhov, Suleiman Mostamandi, Arlindo da Silva, Johannes Flemming, Yasser Alshehri, Illia Shevchenko, and Georgiy Stenchikov
Atmos. Chem. Phys., 20, 9281–9310,Short summary
The data assimilation products MERRA2 and CAMS are tested over the Middle East (ME) against in situ and satellite observations. For the first time, we compared the new MODIS aerosol optical depth (AOD) retrieval, MAIAC, with the Deep Blue and Dark Target MODIS AOD. We conducted 2-year high-resolution WRF-Chem simulations with the most accurate OMI-HTAP SO2 emissions to estimate the contribution of natural and anthropogenic aerosols to the PM pollution in the ME.
Yang Li, Loretta J. Mickley, Pengfei Liu, and Jed O. Kaplan
Atmos. Chem. Phys., 20, 8827–8838,Short summary
Using a coupled vegetation–fire–climate modeling framework, we show a northward shift in forests and increased lightning fire activity in northern US states, including Idaho, Montana, and Wyoming. Our findings suggest a large climate penalty on ecosystem, air quality, visibility, and human health in a region valued for its national forests and parks. The fine-scale smoke PM predictions provided in this study should prove useful to human health and environmental assessments.
Ryan Schmedding, Quazi Z. Rasool, Yue Zhang, Havala O. T. Pye, Haofei Zhang, Yuzhi Chen, Jason D. Surratt, Felipe D. Lopez-Hilfiker, Joel A. Thornton, Allen H. Goldstein, and William Vizuete
Atmos. Chem. Phys., 20, 8201–8225,Short summary
Accurate model prediction of aerosol concentrations is a known challenge. It is assumed in many modeling systems that aerosols are in a homogeneously mixed phase state. It has been observed that aerosols do phase separate and can form a highly viscous organic shell with an aqueous core impacting the formation processes of aerosols. This work is a model implementation to determine an aerosol's phase state using glass transition temperature and aerosol composition.
Lin Tang, Martin O. P. Ramacher, Jana Moldanová, Volker Matthias, Matthias Karl, Lasse Johansson, Jukka-Pekka Jalkanen, Katarina Yaramenka, Armin Aulinger, and Malin Gustafsson
Atmos. Chem. Phys., 20, 7509–7530,Short summary
The effects of shipping emissions on air quality and health in the harbour city of Gothenburg were simulated for 2012 with coupled regional and city-scale chemistry transport models. The results show that contributions of shipping to exposure and health impacts from particulate matter and NO2 are significant and that shipping-related exposure to PM is dominated by emissions from regional shipping outside the city domain and is larger than exposure related to emissions from local road traffic.
Jiani Tan, Joshua S. Fu, Gregory R. Carmichael, Syuichi Itahashi, Zhining Tao, Kan Huang, Xinyi Dong, Kazuyo Yamaji, Tatsuya Nagashima, Xuemei Wang, Yiming Liu, Hyo-Jung Lee, Chuan-Yao Lin, Baozhu Ge, Mizuo Kajino, Jia Zhu, Meigen Zhang, Hong Liao, and Zifa Wang
Atmos. Chem. Phys., 20, 7393–7410,Short summary
This study evaluated the performance of 12 chemical transport models from MICS-Asia III for predicting the particulate matter (PM) over East Asia. Four model processes were investigated as the possible reasons for model bias with measurements and the factors causing inconsistent predictions of PM from different models: (1) model inputs, (2) gas–particle conversion, (3) dust emission modules and (4) removal mechanisms (wet and dry depositions). The influence of each process was discussed.
Jiayue Huang, Lyatt Jaeglé, Qianjie Chen, Becky Alexander, Tomás Sherwen, Mat J. Evans, Nicolas Theys, and Sungyeon Choi
Atmos. Chem. Phys., 20, 7335–7358,Short summary
Large-scale enhancements of tropospheric BrO and the depletion of surface ozone are often observed in the springtime Arctic. Here, we use a chemical transport model to examine the role of sea salt aerosol from blowing snow in explaining these phenomena. We find that our simulation can account for the spatiotemporal variability of satellite observations of BrO. However, the model has difficulty in producing the magnitude of observed ozone depletion events.
Jingyi Li, Haowen Zhang, Qi Ying, Zhijun Wu, Yanli Zhang, Xinming Wang, Xinghua Li, Yele Sun, Min Hu, Yuanhang Zhang, and Jianlin Hu
Atmos. Chem. Phys., 20, 7291–7306,Short summary
Large gaps still exist in modeled and observed secondary organic aerosol (SOA) mass loading and properties. Here we investigated the impacts of water partitioning into organic aerosol and nonideality of the organic–water mixture on SOA over eastern China using a regional 3D model. SOA is increased more significantly in humid and hot environments. Increases in SOA further cause an enhancement of the cooling effects of aerosols. It is crucial to consider the above processes in modeling SOA.
Yanhong Zhu, Andreas Tilgner, Erik Hans Hoffmann, Hartmut Herrmann, Kimitaka Kawamura, Lingxiao Yang, Likun Xue, and Wenxing Wang
Atmos. Chem. Phys., 20, 6725–6747,Short summary
The formation and processing of secondary inorganic and organic compounds at Mt. Tai, the highest mountain on the North China Plain, are modeled using a multiphase chemical model. The concentrations of key radical and non-radical oxidations in the formation processes are investigated. Sensitivity tests assess the impacts of emission data and glyoxal partitioning constants on modeled results. The key precursors of secondary organic compounds are also identified.
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Organic aerosols have been shown to exist often in a semi-solid or amorphous, glassy state. Highly viscous particles behave differently than their well-mixed liquid analogues with consequences for a variety of aerosol processes. Here, we introduce a new predictive mixture viscosity model called AIOMFAC-VISC. It enables us to predict the viscosity of aqueous organic mixtures as a function of temperature and chemical composition, covering the full range of liquid, semi-solid, and glassy states.
Organic aerosols have been shown to exist often in a semi-solid or amorphous, glassy state....