Articles | Volume 13, issue 19
02 Oct 2013
Research article | 02 Oct 2013
A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms
G. Sarwar et al.
No articles found.
Jiandong Wang, Jia Xing, Shuxiao Wang, Rohit Mathur, Jiaping Wang, Yuqiang Zhang, Chao Liu, Jonathan Pleim, Dian Ding, Xing Chang, Jingkun Jiang, Peng Zhao, Shovan Kumar Sahu, Yuzhi Jin, David C. Wong, and Jiming Hao
Atmos. Chem. Phys., 22, 5147–5156,Short summary
Aerosols reduce surface solar radiation and change the photolysis rate and planetary boundary layer stability. In this study, the online coupled meteorological and chemistry model was used to explore the detailed pathway of how aerosol direct effects affect secondary inorganic aerosol. The effects through the dynamics pathway act as an equally or even more important route compared with the photolysis pathway in affecting secondary aerosol concentration in both summer and winter.
Mengying Li, Shaocai Yu, Xue Chen, Zhen Li, Yibo Zhang, Zhe Song, Weiping Liu, Pengfei Li, Xiaoye Zhang, Meigen Zhang, Yele Sun, Zirui Liu, Caiping Sun, Jingkun Jiang, Shuxiao Wang, Benjamin Murphy, Kiran Alapaty, Rohit Mathur, Daniel Rosenfeld, and John Seinfeld
Atmos. Chem. Phys. Discuss.,
Revised manuscript under review for ACPShort summary
This study constructed an emission inventory of Condensable particulate matter (CPM) in China with a focus on organic aerosols (OA) based on collected CPM emission information. Results show that OA emissions are enhanced twofold after the inclusion of CPM in a new China inventory for the years 2014 and 2017. Sensitivity cases demonstrated the significant contributions of CPM emissions from stationary combustion and mobile sources to POA, SOA, and total OA concentrations.
Sarah E. Benish, Jesse O. Bash, Kristen M. Foley, K. Wyat Appel, Christian Hogrefe, Robert Gilliam, and George Pouliot
Atmos. Chem. Phys. Discuss.,
Revised manuscript under review for ACPShort summary
We assess CMAQ model simulations of nitrogen and sulfur deposition over US climate regions to evaluate the model ability to reproduce long-term deposition trends and total deposition budgets. A measurement-model fusion technique is found to improve estimates of wet deposition. Emission controls set by the Clean Air Act successfully decreased oxidized nitrogen deposition across the US and we find increasing amounts of reduced nitrogen to the total nitrogen budget over the simulation time period.
Kai Wang, Yang Zhang, Shaocai Yu, David C. Wong, Jonathan Pleim, Rohit Mathur, James T. Kelly, and Michelle Bell
Geosci. Model Dev., 14, 7189–7221,Short summary
The two-way coupled WRF-CMAQ model accounting for complex chemistry–meteorology feedbacks has been applied to the long-term predictions of regional meteorology and air quality over the US. The model results show superior performance and importance of chemistry–meteorology feedbacks when compared to the offline coupled WRF and CMAQ simulations, which suggests that feedbacks should be considered along with other factors in developing future model applications to inform policy making.
Syuichi Itahashi, Rohit Mathur, Christian Hogrefe, Sergey L. Napelenok, and Yang Zhang
Geosci. Model Dev., 14, 5751–5768,Short summary
The Community Multiscale Air Quality (CMAQ) modeling system extended for hemispheric-scale applications (H-CMAQ) incorporated the satellite-constrained degassing SO2 emissions from 50 volcanos across the Northern Hemisphere. The impact on tropospheric sulfate aerosol (SO42−) is assessed for 2010. Although the considered volcanic emissions occurred at or below the middle of free troposphere (500 hPa), SO42− enhancements of more than 10 % were detected up to the top of free troposphere (250 hPa).
Benjamin N. Murphy, Christopher G. Nolte, Fahim Sidi, Jesse O. Bash, K. Wyat Appel, Carey Jang, Daiwen Kang, James Kelly, Rohit Mathur, Sergey Napelenok, George Pouliot, and Havala O. T. Pye
Geosci. Model Dev., 14, 3407–3420,Short summary
The algorithms for applying air pollution emission rates in the Community Multiscale Air Quality (CMAQ) model have been improved to better support users and developers. The new features accommodate emissions perturbation studies that are typical in atmospheric research and output a wealth of metadata for each model run so assumptions can be verified and documented. The new approach dramatically enhances the transparency and functionality of this critical aspect of atmospheric modeling.
K. Wyat Appel, Jesse O. Bash, Kathleen M. Fahey, Kristen M. Foley, Robert C. Gilliam, Christian Hogrefe, William T. Hutzell, Daiwen Kang, Rohit Mathur, Benjamin N. Murphy, Sergey L. Napelenok, Christopher G. Nolte, Jonathan E. Pleim, George A. Pouliot, Havala O. T. Pye, Limei Ran, Shawn J. Roselle, Golam Sarwar, Donna B. Schwede, Fahim I. Sidi, Tanya L. Spero, and David C. Wong
Geosci. Model Dev., 14, 2867–2897,Short summary
This paper details the scientific updates in the recently released CMAQ version 5.3 (and v5.3.1) and also includes operational and diagnostic evaluations of CMAQv5.3.1 against observations and the previous version of the CMAQ (v5.2.1). This work was done to improve the underlying science in CMAQ. This article is used to inform the CMAQ modeling community of the updates to the modeling system and the expected change in model performance from these updates (versus the previous model version).
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.
Syuichi Itahashi, Rohit Mathur, Christian Hogrefe, and Yang Zhang
Atmos. Chem. Phys., 20, 3373–3396,Short summary
The state-of-the-science Community Multiscale Air Quality model extended for hemispheric applications (H-CMAQ) is used to model the trans-Pacific transport which has been recognized as a potential source of air pollutants over the US. In Part 1, modeled ozone is evaluated with observations at surface, by ozonesonde and airplane, and by satellite across the Northern Hemisphere. In addition, a newly developed air mass characterization method to estimate stratospheric intrusion is presented.
Syuichi Itahashi, Rohit Mathur, Christian Hogrefe, Sergey L. Napelenok, and Yang Zhang
Atmos. Chem. Phys., 20, 3397–3413,Short summary
The state-of-the-science Community Multiscale Air Quality model extended for hemispheric applications (H-CMAQ) is used to model the trans-Pacific transport which has been recognized as a potential source of air pollutants over the US. In Part 2, the higher-order decoupled direct method (HDDM) is applied to investigate the emission impacts from east Asia and the US during April 2010. Furthermore, changes in trans-Pacific transport caused by the recent emissions are examined.
S. Trivikrama Rao, Huiying Luo, Marina Astitha, Christian Hogrefe, Valerie Garcia, and Rohit Mathur
Atmos. Chem. Phys., 20, 1627–1639,Short summary
Since numerical air quality models do not explicitly simulate stochastic variations in the atmosphere, there will always be differences between modeled and measured pollutant levels even when the model's physics, chemistry, numerical analysis, and its input data are perfect. This paper quantifies the inherent uncertainty in regional models due to the stochastic nature of the atmosphere. A knowledge of the expected error helps model developers in evaluating the real progress in improving models.
Daiwen Kang, Kristen M. Foley, Rohit Mathur, Shawn J. Roselle, Kenneth E. Pickering, and Dale J. Allen
Geosci. Model Dev., 12, 4409–4424,Short summary
This paper provides a comprehensive evaluation of the lightning production schemes in CMAQ as described in https://www.geosci-model-dev.net/12/3071/2019/gmd-12-3071-2019.html on model performance. The impact of lightning NOx from different schemes is evaluated in time and space using both ground–level network measurements and aloft (ozonesonde and aircraft) observations. These results provide users the benchmark model performance when the lightning NOx production schemes are applied.
Daiwen Kang, Kenneth E. Pickering, Dale J. Allen, Kristen M. Foley, David C. Wong, Rohit Mathur, and Shawn J. Roselle
Geosci. Model Dev., 12, 3071–3083,Short summary
Lightning strikes produce significant amount of nitrogen oxides and the resulting atmospheric chemistry causes one of the primary air pollutants, ground-level ozone, to change. In this paper, we documented the evolution of scientific updates for lightning-induced nitrogen oxides schemes in the CMAQ model. The updated observation-based schemes are good for retrospective applications, while the parameterized scheme can estimate lightning nitrogen oxides for applications without observations.
Peng Liu, Christian Hogrefe, Ulas Im, Jesper H. Christensen, Johannes Bieser, Uarporn Nopmongcol, Greg Yarwood, Rohit Mathur, Shawn Roselle, and Tanya Spero
Atmos. Chem. Phys., 18, 17157–17175,Short summary
This study represents an intercomparison of four regional-scale air quality simulations in order to understand the model similarities and differences in estimating the impact of ozone imported from outside of the US on the surface ozone within the US at process level. Vertical turbulent mixing stands out as a primary contributor to the model differences in inert tracers.
Yuqiang Zhang, J. Jason West, Rohit Mathur, Jia Xing, Christian Hogrefe, Shawn J. Roselle, Jesse O. Bash, Jonathan E. Pleim, Chuen-Meei Gan, and David C. Wong
Atmos. Chem. Phys., 18, 15003–15016,Short summary
Here we use a fine-resolution (36 km) self-consistent 21-year air quality simulation from 1990 to 2010, a health impact function, and annual county-level population and baseline mortality rate estimates to estimate annual mortality burdens from PM2.5 and O3 in the US, and also the contributions to the trends. We found that the PM2.5-related mortality burden has steadily decreased by 53 %, while the O3-related mortality burden has increased by 13 %, with larger inter-annual variabilities.
Yuqiang Zhang, Rohit Mathur, Jesse O. Bash, Christian Hogrefe, Jia Xing, and Shawn J. Roselle
Atmos. Chem. Phys., 18, 9091–9106,Short summary
For this study, we evaluated the WRF–CMAQ coupled model's ability to simulate the long-term trends of wet deposition of nitrogen and sulfur from 1990 to 2010 by comparing the model results with long-term observation datasets in the US. The model generally underestimates the wet deposition of both nitrogen and sulfur but captured well the decreasing trends for the deposition. Then we estimated the deposition budget in the US, including wet deposition and dry deposition from model simulations.
Stefano Galmarini, Ioannis Kioutsioukis, Efisio Solazzo, Ummugulsum Alyuz, Alessandra Balzarini, Roberto Bellasio, Anna M. K. Benedictow, Roberto Bianconi, Johannes Bieser, Joergen Brandt, Jesper H. Christensen, Augustin Colette, Gabriele Curci, Yanko Davila, Xinyi Dong, Johannes Flemming, Xavier Francis, Andrea Fraser, Joshua Fu, Daven K. Henze, Christian Hogrefe, Ulas Im, Marta Garcia Vivanco, Pedro Jiménez-Guerrero, Jan Eiof Jonson, Nutthida Kitwiroon, Astrid Manders, Rohit Mathur, Laura Palacios-Peña, Guido Pirovano, Luca Pozzoli, Marie Prank, Martin Schultz, Rajeet S. Sokhi, Kengo Sudo, Paolo Tuccella, Toshihiko Takemura, Takashi Sekiya, and Alper Unal
Atmos. Chem. Phys., 18, 8727–8744,Short summary
An ensemble of model results relating to ozone concentrations in Europe in 2010 has been produced and studied. The novelty consists in the fact that the ensemble is made of results of models working at two different scales (regional and global), therefore contributing in detail two different parts of the atmospheric spectrum. The ensemble defined as a hybrid has been studied in detail and shown to bring additional value to the assessment of air quality.
Christian Hogrefe, Peng Liu, George Pouliot, Rohit Mathur, Shawn Roselle, Johannes Flemming, Meiyun Lin, and Rokjin J. Park
Atmos. Chem. Phys., 18, 3839–3864,Short summary
This study quantifies the impacts of different representations of background ozone in state-of-the-science large-scale models on surface and aloft ozone burdens simulated by the CMAQ regional model over the United States. It also compares both the CMAQ simulations and the driving large-scale models to surface and upper air observations.
Jingqiu Mao, Annmarie Carlton, Ronald C. Cohen, William H. Brune, Steven S. Brown, Glenn M. Wolfe, Jose L. Jimenez, Havala O. T. Pye, Nga Lee Ng, Lu Xu, V. Faye McNeill, Kostas Tsigaridis, Brian C. McDonald, Carsten Warneke, Alex Guenther, Matthew J. Alvarado, Joost de Gouw, Loretta J. Mickley, Eric M. Leibensperger, Rohit Mathur, Christopher G. Nolte, Robert W. Portmann, Nadine Unger, Mika Tosca, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 2615–2651,Short summary
This paper is aimed at discussing progress in evaluating, diagnosing, and improving air quality and climate modeling using comparisons to SAS observations as a guide to thinking about improvements to mechanisms and parameterizations in models.
Rohit Mathur, Jia Xing, Robert Gilliam, Golam Sarwar, Christian Hogrefe, Jonathan Pleim, George Pouliot, Shawn Roselle, Tanya L. Spero, David C. Wong, and Jeffrey Young
Atmos. Chem. Phys., 17, 12449–12474,Short summary
We extend CMAQ's applicability to the entire Northern Hemisphere to enable consistent examination of interactions between atmospheric processes occurring on various spatial and temporal scales. Improvements were made in model process representation, structure, and input data sets that enable a range of model applications including episodic intercontinental pollutant transport, long-term trends in air pollution across the Northern Hemisphere, and air pollution–climate interactions.
Jia Xing, Jiandong Wang, Rohit Mathur, Shuxiao Wang, Golam Sarwar, Jonathan Pleim, Christian Hogrefe, Yuqiang Zhang, Jingkun Jiang, David C. Wong, and Jiming Hao
Atmos. Chem. Phys., 17, 9869–9883,Short summary
The assessment of the impacts of aerosol direct effects (ADE) is important for understanding emission reduction strategies that seek co-benefits associated with reductions in both particulate matter and ozone. This study quantifies the ADE impacts on tropospheric ozone by using a two-way coupled meteorology and atmospheric chemistry model. Results suggest that reducing ADE may have the potential risk of increasing ozone in winter, but it will benefit the reduction of maxima ozone in summer.
K. Wyat Appel, Sergey L. Napelenok, Kristen M. Foley, Havala O. T. Pye, Christian Hogrefe, Deborah J. Luecken, Jesse O. Bash, Shawn J. Roselle, Jonathan E. Pleim, Hosein Foroutan, William T. Hutzell, George A. Pouliot, Golam Sarwar, Kathleen M. Fahey, Brett Gantt, Robert C. Gilliam, Nicholas K. Heath, Daiwen Kang, Rohit Mathur, Donna B. Schwede, Tanya L. Spero, David C. Wong, and Jeffrey O. Young
Geosci. Model Dev., 10, 1703–1732,Short summary
The Community Multiscale Air Quality (CMAQ) model is a comprehensive multipollutant air quality modeling system. The CMAQ model is used extensively throughout the world to simulate air pollutants for many purposes, including regulatory and air quality forecasting applications. This work describes the scientific updates made to the latest version of the CMAQ modeling system (CMAQv5.1) and presents an evaluation of the new model against observations and results from the previous model version.
Jia Xing, Rohit Mathur, Jonathan Pleim, Christian Hogrefe, Jiandong Wang, Chuen-Meei Gan, Golam Sarwar, David C. Wong, and Stuart McKeen
Atmos. Chem. Phys., 16, 10865–10877,Short summary
Downward transport of ozone from the stratosphere has large impacts on surface concentration and needs to be properly represented in regional models. This study developed a seasonally and spatially varying PV-based function from an investigation of the relationship between PV and O3. The implementation of the new function significantly improves the model's performance in O3 simulation, which enables a more accurate simulation of the vertical distribution of O3 across the Northern Hemisphere.
C.-M. Gan, J. Pleim, R. Mathur, C. Hogrefe, C. N. Long, J. Xing, D. Wong, R. Gilliam, and C. Wei
Atmos. Chem. Phys., 15, 12193–12209,Short summary
This study attempts to determine the consequences of the changes in tropospheric aerosol burden arising from substantial reductions in emissions of SO2 and NOx associated with control measures under the Clean Air Act especially on trends in solar radiation. Comparisons of model results with observations of aerosol optical depth, aerosol concentration, and radiation demonstrate that the coupled WRF-CMAQ model is capable of replicating the trends well even though it tends to underestimate the AOD.
G. Janssens-Maenhout, M. Crippa, D. Guizzardi, F. Dentener, M. Muntean, G. Pouliot, T. Keating, Q. Zhang, J. Kurokawa, R. Wankmüller, H. Denier van der Gon, J. J. P. Kuenen, Z. Klimont, G. Frost, S. Darras, B. Koffi, and M. Li
Atmos. Chem. Phys., 15, 11411–11432,Short summary
This paper provides monthly emission grid maps at 0.1deg x 0.1deg resolution with global coverage for air pollutants and aerosols anthropogenic emissions in 2008 and 2010. Countries are consistently inter-compared with sector-specific implied emission factors, per capita emissions and emissions per unit of GDP. The emission grid maps compose the reference emissions data set for the community modelling hemispheric transport of air pollution (HTAP).
J.-M. Yoo, M.-J. Jeong, D. Kim, W. R. Stockwell, J.-H. Yang, H.-W. Shin, M.-I. Lee, C.-K. Song, and S.-D. Lee
Atmos. Chem. Phys., 15, 10857–10885,Short summary
Major air pollutants (O3, NO2, SO2, CO, PM10, and VOCs) with long-term records from a dense observation network over Korea were extensively analyzed with land-use types, classified by Korean government, consistent with satellite-observed land covers. The weekly cycles of the pollutant showed different behaviors with the types. Regardless of land-use types, ozone has an increasing trend, while the other pollutants have decreasing trends. Most areas in Korea were VOCs-limited for ozone chemistry.
C. G. Nolte, K. W. Appel, J. T. Kelly, P. V. Bhave, K. M. Fahey, J. L. Collett Jr., L. Zhang, and J. O. Young
Geosci. Model Dev., 8, 2877–2892,Short summary
This study is the most comprehensive evaluation of CMAQ inorganic aerosol size-composition distributions conducted to date. We compare two methods of inferring PM2.5 concentrations from the model: (1) based on the sum of the masses in the fine aerosol modes, as is most commonly done in CMAQ model evaluation; and (2) computed using the simulated size distributions. Differences are generally less than 1 microgram/m3, and are largest over the eastern USA during the summer.
J. Xing, R. Mathur, J. Pleim, C. Hogrefe, C.-M. Gan, D. C. Wong, and C. Wei
Atmos. Chem. Phys., 15, 9997–10018,Short summary
The ability of a coupled meteorology-chemistry model (WRF-CMAQ) to reproduce the historical trend in AOD and clear-sky SWR over the N. Hemisphere has been evaluated through a comparison of 21-year simulated results with observation-derived records from 1990 to 2010. Questions of how well the model represents the regional and temporal variability of aerosol burden and DRE, and whether the model is able to capture past trends in aerosol loading and associated radiation effects, will be addressed.
J. Xing, R. Mathur, J. Pleim, C. Hogrefe, C.-M. Gan, D. C. Wong, C. Wei, R. Gilliam, and G. Pouliot
Atmos. Chem. Phys., 15, 2723–2747,Short summary
Model-simulated air quality trends over the past 2 decades largely agree with those derived from observations. In the relative amounts of VOC and NOx emission controls in different regions across the northern hemisphere have led to significantly different trends in tropospheric O3. Differences in the historical changes in the relative amounts of NH3, NOx and SO2 emissions also impact the trends in inorganic particulate matter amounts and composition in China, the U.S. and Europe.
S. Yu, R. Mathur, J. Pleim, D. Wong, R. Gilliam, K. Alapaty, C. Zhao, and X. Liu
Atmos. Chem. Phys., 14, 11247–11285,
W. Zhou, D. S. Cohan, and B. H. Henderson
Atmos. Chem. Phys., 14, 2777–2788,
B. H. Henderson, F. Akhtar, H. O. T. Pye, S. L. Napelenok, and W. T. Hutzell
Geosci. Model Dev., 7, 339–360,
C.-M. Gan, J. Pleim, R. Mathur, C. Hogrefe, C. N. Long, J. Xing, S. Roselle, and C. Wei
Atmos. Chem. Phys., 14, 1701–1715,
Y. Xie, F. Paulot, W. P. L. Carter, C. G. Nolte, D. J. Luecken, W. T. Hutzell, P. O. Wennberg, R. C. Cohen, and R. W. Pinder
Atmos. Chem. Phys., 13, 8439–8455,
J. Xing, J. Pleim, R. Mathur, G. Pouliot, C. Hogrefe, C.-M. Gan, and C. Wei
Atmos. Chem. Phys., 13, 7531–7549,
K. W. Appel, G. A. Pouliot, H. Simon, G. Sarwar, H. O. T. Pye, S. L. Napelenok, F. Akhtar, and S. J. Roselle
Geosci. Model Dev., 6, 883–899,
Related subject area
Subject: Gases | Research Activity: Atmospheric Modelling | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)Observation-based analysis of ozone production sensitivity for two persistent ozone episodes in Guangdong, ChinaA machine learning approach to quantify meteorological drivers of ozone pollution in China from 2015 to 2019Discrepancy in assimilated atmospheric CO over East Asia in 2015–2020 by assimilating satellite and surface CO measurementsPotential environmental impact of bromoform from Asparagopsis farming in AustraliaSatellite soil moisture data assimilation impacts on modeling weather variables and ozone in the southeastern US – Part 2: Sensitivity to dry-deposition parameterizationsThe impacts of marine-emitted halogens on OH radicals in East Asia during summerImpact of eastern and central Pacific El Niño on lower tropospheric ozone in ChinaContribution of Asian emissions to upper tropospheric CO over the remote PacificAn ensemble-variational inversion system for the estimation of ammonia emissions using CrIS satellite ammonia retrievalsA process-oriented evaluation of CAMS reanalysis ozone during tropopause folds over Europe for the period 2003–2018Estimation of mechanistic parameters in the gas-phase reactions of ozone with alkenes for use in automated mechanism constructionProjections of hydrofluorocarbon (HFC) emissions and the resulting global warming based on recent trends in observed abundances and current policiesQuantification of methane emissions from hotspots and during COVID-19 using a global atmospheric inversionModel evaluation of short-lived climate forcers for the Arctic Monitoring and Assessment Programme: a multi-species, multi-model studyGlobal simulations of monoterpene-derived peroxy radical fates and the distributions of highly oxygenated organic molecules (HOMs) and accretion productsA model for simultaneous evaluation of NO2, O3 and PM10 pollution in urban and rural areas: handling incomplete data sets with multivariate curve resolution analysisInfluence of photochemical loss of volatile organic compounds on understanding ozone formation mechanismNorth China Plain as a hot spot of ozone pollution exacerbated by extreme high temperaturesPhotochemical evolution of the 2013 California Rim Fire: synergistic impacts of reactive hydrocarbons and enhanced oxidantsImpact of biomass burning and stratospheric intrusions in the remote South Pacific Ocean troposphereInfluence of total ozone column (TOC) on the occurrence of tropospheric ozone depletion events (ODEs) in the AntarcticChanges in anthropogenic precursor emissions drive shifts in the ozone seasonal cycle throughout the northern midlatitude troposphereAmplified role of potential HONO sources in O3 formation in North China Plain during autumn haze aggravating processesImproving NOX emissions in Beijing using network observations and a novel perturbed emissions ensembleContinental-scale contributions to the global CFC-11 emission increase between 2012 and 2017Surface ozone impacts on major crop production in China from 2010 to 2017Enhanced summertime ozone and SOA from biogenic volatile organic compound (BVOC) emissions due to vegetation biomass variability during 1981–2018 in ChinaPyruvic acid, an efficient catalyst in SO3 hydrolysis and effective clustering agent in sulfuric-acid-based new particle formationTropospheric ozone changes and ozone sensitivity from the present day to the future under shared socio-economic pathwaysAn integrated analysis of contemporary methane emissions and concentration trends over China using in situ and satellite observations and model simulationsAn assessment of the tropospherically accessible photo-initiated ground state chemistry of organic carbonylsMethane emissions in the United States, Canada, and Mexico: evaluation of national methane emission inventories and 2010–2017 sectoral trends by inverse analysis of in situ (GLOBALVIEWplus CH4 ObsPack) and satellite (GOSAT) atmospheric observationsEvaluation of SO2, SO42− and an updated SO2 dry deposition parameterization in the United Kingdom Earth System ModelDevelopment and evaluation of a new compact mechanism for aromatic oxidation in atmospheric modelsOzone deposition impact assessments for forest canopies require accurate ozone flux partitioning on diurnal timescalesUnraveling pathways of elevated ozone induced by the 2020 lockdown in Europe by an observationally constrained regional model using TROPOMICloud-scale modelling of the impact of deep convection on the fate of oceanic bromoform in the troposphere: a case study over the west coast of BorneoImproving predictability of high-ozone episodes through dynamic boundary conditions, emission refresh and chemical data assimilation during the Long Island Sound Tropospheric Ozone Study (LISTOS) field campaignAtmospheric observations consistent with reported decline in the UK's methane emissions (2013–2020)Influence of atmospheric in-cloud aqueous-phase chemistry on the global simulation of SO2 in CESM2Technical note: Quality assessment of ozone reanalysis products and gap-filling over subarctic Europe for vegetation risk mappingEvolution of OH reactivity in NO-free volatile organic compound photooxidation investigated by the fully explicit GECKO-A modelImpact of pyruvic acid photolysis on acetaldehyde and peroxy radical formation in the boreal forest: theoretical calculations and model resultsEvaluating consistency between total column CO2 retrievals from OCO-2 and the in situ network over North America: implications for carbon flux estimationTechnical note: Entrainment-limited kinetics of bimolecular reactions in cloudsGlobal tropospheric halogen (Cl, Br, I) chemistry and its impact on oxidantsThe role of emission reductions and the meteorological situation for air quality improvements during the COVID-19 lockdown period in central EuropeHeterogeneity and chemical reactivity of the remote troposphere defined by aircraft measurementsA mass-balance-based emission inventory of non-methane volatile organic compounds (NMVOCs) for solvent use in ChinaOpinion: The germicidal effect of ambient air (open-air factor) revisited
Kaixiang Song, Run Liu, Yu Wang, Tao Liu, Liyan Wei, Yanxing Wu, Junyu Zheng, Boguang Wang, and Shaw Chen Liu
Atmos. Chem. Phys., 22, 8403–8416,Short summary
We developed an observation-based method to investigate the sensitivity of ozone formation to precursors during two elevated ozone episodes observed at 77 stations in Guangdong, China. We found approximately 67 % of the station days exhibit ozone formation sensitivity to NOx, 20 % of the station days are in the transitional regime sensitive to both NOx and volatile organic compounds (VOCs), and only 13 % of the station days are sensitive to VOCs.
Xiang Weng, Grant L. Forster, and Peer Nowack
Atmos. Chem. Phys., 22, 8385–8402,Short summary
We use machine learning to quantify the meteorological drivers behind surface ozone variations in China between 2015 and 2019. Our novel approaches show improved performance when compared to previous analysis methods. We highlight that nonlinearity in driver relationships and the impacts of large-scale meteorological phenomena are key to understanding ozone pollution. Moreover, we find that almost half of the observed ozone trend between 2015 and 2019 might have been driven by meteorology.
Zhaojun Tang, Jiaqi Chen, and Zhe Jiang
Atmos. Chem. Phys., 22, 7815–7826,Short summary
We provide a comparative analysis to explore the effects of satellite and surface measurements on atmospheric CO in data assimilations in 2015–2020 over East Asia. We find possible overestimated enhancements of atmospheric CO by assimilating surface CO measurements due to model representation errors, and a large discrepancy in the derived trends of CO columns due to different vertical sensitivities of satellite and surface observations to lower and free troposphere.
Yue Jia, Birgit Quack, Robert D. Kinley, Ignacio Pisso, and Susann Tegtmeier
Atmos. Chem. Phys., 22, 7631–7646,Short summary
In this study, we assessed the potential risks of bromoform released from Asparagopsis farming near Australia for the stratospheric ozone layer by analyzing different cultivation scenarios. We conclude that the intended operation of Asparagopsis seaweed cultivation farms with an annual yield to meet the needs of 50 % of feedlots and cattle in either open-ocean or terrestrial cultures in Australia will not impact the ozone layer under normal operating conditions.
Min Huang, James H. Crawford, Gregory R. Carmichael, Kevin W. Bowman, Sujay V. Kumar, and Colm Sweeney
Atmos. Chem. Phys., 22, 7461–7487,Short summary
This study demonstrates that ozone dry-deposition modeling can be improved by revising the model's dry-deposition parameterizations to better represent the effects of environmental conditions including the soil moisture fields. Applying satellite soil moisture data assimilation is shown to also have added value. Such advancements in coupled modeling and data assimilation can benefit the assessments of ozone impacts on human and vegetation health.
Shidong Fan and Ying Li
Atmos. Chem. Phys., 22, 7331–7351,Short summary
We investigated the mechanisms by which marine-emitted halogens influence the OH radical, which is not considered in air quality forecasting model systems. The atmospheric OH radical has a complicated response to halogen emissions by species through both physical and chemical processes. Over ocean, inorganic iodine is the controlling species and chemistry is more important. Over land, the physics of sea salt aerosols are more important. The mechanism is applicable to other circumstances.
Zhongjing Jiang and Jing Li
Atmos. Chem. Phys., 22, 7273–7285,Short summary
This study investigates the changes of tropospheric ozone in China associated with EP and CP El Niño, using satellite observations and the GEOS-Chem model. We found that El Niño generally leads to lower tropospheric ozone (LTO) decrease over most parts of China; La Niña acts the opposite. The difference between LTO changes during EP and CP El Niño primarily lies in southern China. Regional transport and chemical processes play the leading and secondary roles in driving the LTO changes.
Linda Smoydzin and Peter Hoor
Atmos. Chem. Phys., 22, 7193–7206,Short summary
Our study presents a detailed analysis of the spatial and temporal distribution of elevated CO level in the upper troposphere over the Pacific using 20 years of MOPITT data. We create a climatology of severe pollution episodes and use trajectory calculations to link each particular pollution event detected in MOPITT satellite data with a distinct source region. Additionally, we analyse uplift mechanisms such as WCB-related upward transport.
Michael Sitwell, Mark W. Shephard, Yves Rochon, Karen Cady-Pereira, and Enrico Dammers
Atmos. Chem. Phys., 22, 6595–6624,Short summary
Observations of ammonia made using the satellite-borne CrIS instrument were used to improve the ammonia emissions used in the GEM-MACH model. These observations were used to refine estimates of the monthly mean ammonia emissions over North America for May to August 2016. The updated ammonia emissions reduced biases of GEM-MACH surface ammonia fields with surface observations and showed some improvements in the forecasting of species involved in inorganic particulate matter formation.
Dimitris Akritidis, Andrea Pozzer, Johannes Flemming, Antje Inness, Philippe Nédélec, and Prodromos Zanis
Atmos. Chem. Phys., 22, 6275–6289,Short summary
We perform a process-oriented evaluation of Copernicus Atmosphere Monitoring Service (CAMS) reanalysis (CAMSRA) O3 over Europe using WOUDC (World Ozone and Ultraviolet Radiation Data Centre) ozonesondes and IAGOS (In-service Aircraft for a Global Observing System) aircraft measurements. Chemical data assimilation assists CAMSRA to reproduce the observed O3 increases in the troposphere during the examined folding events, but it mostly results in O3 overestimation in the upper troposphere.
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,Short summary
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.
Guus J. M. Velders, John S. Daniel, Stephen A. Montzka, Isaac Vimont, Matthew Rigby, Paul B. Krummel, Jens Muhle, Simon O'Doherty, Ronald G. Prinn, Ray F. Weiss, and Dickon Young
Atmos. Chem. Phys., 22, 6087–6101,Short summary
The emissions of hydrofluorocarbons (HFCs) have increased significantly in the past as a result of the phasing out of ozone-depleting substances. Observations indicate that HFCs are used much less in certain refrigeration applications than previously projected. Current policies are projected to reduce emissions and the surface temperature contribution of HFCs from 0.28–0.44 °C to 0.14–0.31 °C in 2100. The Kigali Amendment is projected to reduce the contributions further to 0.04 °C in 2100.
Joe McNorton, Nicolas Bousserez, Anna Agustí-Panareda, Gianpaolo Balsamo, Luca Cantarello, Richard Engelen, Vincent Huijnen, Antje Inness, Zak Kipling, Mark Parrington, and Roberto Ribas
Atmos. Chem. Phys., 22, 5961–5981,Short summary
Concentrations of atmospheric methane continue to grow, in recent years at an increasing rate, for unknown reasons. Using newly available satellite observations and a state-of-the-art weather prediction model we perform global estimates of emissions from hotspots at high resolution. Results show that the system can accurately report on biases in national inventories and is used to conclude that the early COVID-19 slowdown period (March–June 2020) had little impact on global methane emissions.
Cynthia H. Whaley, Rashed Mahmood, Knut von Salzen, Barbara Winter, Sabine Eckhardt, Stephen Arnold, Stephen Beagley, Silvia Becagli, Rong-You Chien, Jesper Christensen, Sujay Manish Damani, Xinyi Dong, Konstantinos Eleftheriadis, Nikolaos Evangeliou, Gregory Faluvegi, Mark Flanner, Joshua S. Fu, Michael Gauss, Fabio Giardi, Wanmin Gong, Jens Liengaard Hjorth, Lin Huang, Ulas Im, Yugo Kanaya, Srinath Krishnan, Zbigniew Klimont, Thomas Kühn, Joakim Langner, Kathy S. Law, Louis Marelle, Andreas Massling, Dirk Olivié, Tatsuo Onishi, Naga Oshima, Yiran Peng, David A. Plummer, Olga Popovicheva, Luca Pozzoli, Jean-Christophe Raut, Maria Sand, Laura N. Saunders, Julia Schmale, Sangeeta Sharma, Ragnhild Bieltvedt Skeie, Henrik Skov, Fumikazu Taketani, Manu A. Thomas, Rita Traversi, Kostas Tsigaridis, Svetlana Tsyro, Steven Turnock, Vito Vitale, Kaley A. Walker, Minqi Wang, Duncan Watson-Parris, and Tahya Weiss-Gibbons
Atmos. Chem. Phys., 22, 5775–5828,Short summary
Air pollutants, like ozone and soot, play a role in both global warming and air quality. Atmospheric models are often used to provide information to policy makers about current and future conditions under different emissions scenarios. In order to have confidence in those simulations, in this study we compare simulated air pollution from 18 state-of-the-art atmospheric models to measured air pollution in order to assess how well the models perform.
Ruochong Xu, Joel A. Thornton, Ben H. Lee, Yanxu Zhang, Lyatt Jaeglé, Felipe D. Lopez-Hilfiker, Pekka Rantala, and Tuukka Petäjä
Atmos. Chem. Phys., 22, 5477–5494,Short summary
Monoterpenes are emitted into the atmosphere by vegetation and by the use of certain consumer products. Reactions of monoterpenes in the atmosphere lead to low-volatility products that condense to grow particulate matter or participate in new particle formation and, thus, affect air quality and climate. We use a model of atmospheric chemistry and transport to evaluate the global-scale importance of recent updates to our understanding of monoterpene chemistry in particle formation and growth.
Eva Gorrochategui, Isabel Hernandez, and Romà Tauler
A multiway methodology is proposed to handle complex and incomplete atmospheric data sets, providing concise and easy interpretable results. Changes in air quality by NO2, O3 and PM10 in 8 sampling stations located in Catalonia during the COVID-19 lockdown with respect to previous years (2018 and 2019) are investigated. Simultaneous analysis of the 3 contaminants among the 8 stations and for the 3 years allows the evaluation of correlations among the pollutants even when having missing data.
Wei Ma, Zemin Feng, Junlei Zhan, Yongchun Liu, Pengfei Liu, Chengtang Liu, Qingxin Ma, Kang Yang, Yafei Wang, Hong He, Markku Kulmala, Yujing Mu, and Junfeng Liu
Atmos. Chem. Phys., 22, 4841–4851,Short summary
The influence of photochemical loss of volatile organic compounds (VOCS) on O3 formation is investigated using an observation-based model. The sensitivity regime of ozone formation might be misdiagnosed due to the photochemical loss of VOCs in the atmosphere. The contribution of local photochemistry is underestimated regarding O3 pollution when one does not consider the photochemical loss of VOCs.
Pinya Wang, Yang Yang, Huimin Li, Lei Chen, Ruijun Dang, Daokai Xue, Baojie Li, Jianping Tang, L. Ruby Leung, and Hong Liao
Atmos. Chem. Phys., 22, 4705–4719,Short summary
China is now suffering from both severe ozone (O3) pollution and heat events. We highlight that North China Plain is the hot spot of the co-occurrences of extremes in O3 and high temperatures in China. Such coupled extremes exhibit an increasing trend during 2014–2019 and will continue to increase until the middle of this century. And the coupled extremes impose more severe health impacts to human than O3 pollution occurring alone because of elevated O3 levels and temperatures.
Glenn M. Wolfe, Thomas F. Hanisco, Heather L. Arkinson, Donald R. Blake, Armin Wisthaler, Tomas Mikoviny, Thomas B. Ryerson, Ilana Pollack, Jeff Peischl, Paul O. Wennberg, John D. Crounse, Jason M. St. Clair, Alex Teng, L. Gregory Huey, Xiaoxi Liu, Alan Fried, Petter Weibring, Dirk Richter, James Walega, Samuel R. Hall, Kirk Ullmann, Jose L. Jimenez, Pedro Campuzano-Jost, T. Paul Bui, Glenn Diskin, James R. Podolske, Glen Sachse, and Ronald C. Cohen
Atmos. Chem. Phys., 22, 4253–4275,Short summary
Smoke plumes are chemically complex. This work combines airborne observations of smoke plume composition with a photochemical model to probe the production of ozone and the fate of reactive gases in the outflow of a large wildfire. Model–measurement comparisons illustrate how uncertain emissions and chemical processes propagate into simulated chemical evolution. Results provide insight into how this system responds to perturbations, which can help guide future observation and modeling efforts.
Nikos Daskalakis, Laura Gallardo, Maria Kanakidou, Johann Rasmus Nüß, Camilo Menares, Roberto Rondanelli, Anne M. Thompson, and Mihalis Vrekoussis
Atmos. Chem. Phys., 22, 4075–4099,Short summary
Forest fires emit carbon monoxide (CO) that can be transported into the atmosphere far from the sources and reacts to produce ozone (O3) that affects climate, ecosystems and health. O3 is also produced in the stratosphere and can be transported downwards. Using a global numerical model, we found that forest fires can affect CO and O3 even in the South Pacific, the most pristine region of the global ocean, but transport from the stratosphere is a more important O3 source than fires in the region.
Le Cao, Linjie Fan, Simeng Li, and Shuangyan Yang
Atmos. Chem. Phys., 22, 3875–3890,Short summary
We analyzed the observational data and used models to discover the impact of the total ozone column (TOC) on the occurrence of tropospheric ozone depletion events (ODE) in the Antarctic. The results suggest that the decrease of TOC favors the occurrence of ODE. When TOC varies the rates of major ODE accelerating reactions are substantially altered but the rates of major ODE decelerating reactions remain unchanged. As a result, the occurrence of ODE negatively depends on the TOC.
Henry Bowman, Steven Turnock, Susanne E. Bauer, Kostas Tsigaridis, Makoto Deushi, Naga Oshima, Fiona M. O'Connor, Larry Horowitz, Tongwen Wu, Jie Zhang, Dagmar Kubistin, and David D. Parrish
Atmos. Chem. Phys., 22, 3507–3524,Short summary
A full understanding of ozone in the troposphere requires investigation of its temporal variability over all timescales. Model simulations show that the northern midlatitude ozone seasonal cycle shifted with industrial development (1850–2014), with an increasing magnitude and a later summer peak. That shift reached a maximum in the mid-1980s, followed by a reversal toward the preindustrial cycle. The few available observations, beginning in the 1970s, are consistent with the model simulations.
Jingwei Zhang, Chaofan Lian, Weigang Wang, Maofa Ge, Yitian Guo, Haiyan Ran, Yusheng Zhang, Feixue Zheng, Xiaolong Fan, Chao Yan, Kaspar R. Daellenbach, Yongchun Liu, Markku Kulmala, and Junling An
Atmos. Chem. Phys., 22, 3275–3302,Short summary
This study added six potential HONO sources to the WRF-Chem model, evaluated their impact on HONO and O3 concentrations, including surface and vertical concentrations. The simulations extend our knowledge on atmospheric HONO sources, especially for nitrate photolysis. The study also explains the HONO difference in O3 formation on clean and hazy days, and reveals key potential HONO sources to O3 enhancements in haze-aggravating processes with a co-occurrence of high PM2.5 and O3 concentrations.
Le Yuan, Olalekan Popoola, Christina Hood, David Carruthers, Roderic L. Jones, Haitong Zhe Sun, Huan Liu, Qiang Zhang, and Alexander T. Archibald
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Emission estimates represent a major source of uncertainty in air quality modelling. We developed a novel approach to improve emission estimates from existing emissions inventories using air quality models and routine in situ observations. Using this approach, we derived estimates of NOX emissions from the transport sector in Beijing in 2016. This approach has great potential in deriving timely updates of emissions for other pollutants, particularly in regions undergoing rapid emission changes.
Lei Hu, Stephen A. Montzka, Fred Moore, Eric Hintsa, Geoff Dutton, M. Carolina Siso, Kirk Thoning, Robert W. Portmann, Kathryn McKain, Colm Sweeney, Isaac Vimont, David Nance, Bradley Hall, and Steven Wofsy
Atmos. Chem. Phys., 22, 2891–2907,Short summary
The unexpected increase in CFC-11 emissions between 2012 and 2017 resulted in concerns about delaying the stratospheric ozone recovery. Although the subsequent decline of CFC-11 emissions indicated a mitigation in part to this problem, the regions fully responsible for these large emission changes were unclear. Here, our new estimate, based on atmospheric measurements from two global campaigns and from NOAA, suggests Asia primarily contributed to the global CFC-11 emission rise during 2012–2017.
Dianyi Li, Drew Shindell, Dian Ding, Xiao Lu, Lin Zhang, and Yuqiang Zhang
Atmos. Chem. Phys., 22, 2625–2638,Short summary
In this study, we applied chemical transport model simulation with the latest annual anthropogenic emission inventory to study the long-term trend of ozone-induced crop production losses from 2010 to 2017 in China. We find that overall the ozone-induced crop production loss in China is significant and the annual average economic losses for wheat, rice, maize, and soybean in China are USD 9.55 billion, USD 8.53 billion, USD 2.23 billion, and USD 1.16 billion respectively, over the 8 years.
Jing Cao, Shuping Situ, Yufang Hao, Shaodong Xie, and Lingyu Li
Atmos. Chem. Phys., 22, 2351–2364,Short summary
Based on localized emission factors and high-resolution vegetation data, we simulated the impacts of BVOC emissions on O3 and SOA during 1981–2018 in China. The interannual variation of BVOC emissions caused by increasing leaf biomass resulted in O3 and SOA concentrations increasing at average annual rates of 0.11 ppb and 0.008 μg m−3, respectively. The results show different variations which can be attributed to the different changing trends of leaf biomass by region and vegetation type.
Narcisse Tsona Tchinda, Lin Du, Ling Liu, and Xiuhui Zhang
Atmos. Chem. Phys., 22, 1951–1963,Short summary
This study explores the effect of pyruvic acid (PA) both in the SO3 hydrolysis and in sulfuric-acid-based aerosol formation. Results show that in dry and polluted areas, PA-catalyzed SO3 hydrolysis is about 2 orders of magnitude more efficient at forming sulfuric acid than the water-catalyzed reaction. Moreover, PA can effectively enhance the ternary SA-PA-NH3 particle formation rate by up to 4.7×102 relative to the binary SA-NH3 particle formation rate at cold temperatures.
Zhenze Liu, Ruth M. Doherty, Oliver Wild, Fiona M. O'Connor, and Steven T. Turnock
Atmos. Chem. Phys., 22, 1209–1227,Short summary
Tropospheric ozone is important to future air quality and climate, and changing emissions and climate influence ozone. We investigate the evolution of ozone and ozone sensitivity from the present day (2004–2014) to the future (2045–2055) and explore the main drivers of ozone changes from global and regional perspectives. This helps guide suitable emission control strategies to mitigate ozone pollution.
Haiyue Tan, Lin Zhang, Xiao Lu, Yuanhong Zhao, Bo Yao, Robert J. Parker, and Hartmut Boesch
Atmos. Chem. Phys., 22, 1229–1249,Short summary
Methane is the second most important anthropogenic greenhouse gas. Understanding methane emissions and concentration growth over China in the past decade is important to support its mitigation. This study analyzes the contributions of methane emissions from different regions and sources over the globe to methane changes over China in 2007–2018. Our results show strong international transport influences and emphasize the need of intensive methane measurements covering eastern China.
Keiran N. Rowell, Scott H. Kable, and Meredith J. T. Jordan
Atmos. Chem. Phys., 22, 929–949,Short summary
Sunlight drives chemical reactions in the atmosphere by breaking chemical bonds. Motivated by the knowledge that if we can better understand the fundamental chemistry, we will be better able to predict atmospheric composition and model any future changes, we use quantum chemistry to investigate new classes of atmospheric reactions. We identify several potentially important reaction classes that will have implications for the atmospheric production of organic acids and molecular hydrogen.
Xiao Lu, Daniel J. Jacob, Haolin Wang, Joannes D. Maasakkers, Yuzhong Zhang, Tia R. Scarpelli, Lu Shen, Zhen Qu, Melissa P. Sulprizio, Hannah Nesser, A. Anthony Bloom, Shuang Ma, John R. Worden, Shaojia Fan, Robert J. Parker, Hartmut Boesch, Ritesh Gautam, Deborah Gordon, Michael D. Moran, Frances Reuland, Claudia A. Octaviano Villasana, and Arlyn Andrews
Atmos. Chem. Phys., 22, 395–418,Short summary
We evaluate methane emissions and trends for 2010–2017 in the gridded national emission inventories for the United States, Canada, and Mexico by inversion of in situ and satellite methane observations. We find that anthropogenic methane emissions for all three countries are underestimated in the national inventories, largely driven by oil emissions. Anthropogenic methane emissions in the US peak in 2014, in contrast to the report of a steadily decreasing trend over 2010–2017 from the US EPA.
Catherine Hardacre, Jane P. Mulcahy, Richard J. Pope, Colin G. Jones, Steven T. Rumbold, Can Li, Colin Johnson, and Steven T. Turnock
Atmos. Chem. Phys., 21, 18465–18497,Short summary
We investigate UKESM1's ability to represent the sulfur (S) cycle in the recent historical period. The S cycle is a key driver of historical radiative forcing. Earth system models such as UKESM1 should represent the S cycle well so that we can have confidence in their projections of future climate. We compare UKESM1 to observations of sulfur compounds, finding that the model generally performs well. We also identify areas for UKESM1’s development, focussing on how SO2 is removed from the air.
Kelvin H. Bates, Daniel J. Jacob, Ke Li, Peter D. Ivatt, Mat J. Evans, Yingying Yan, and Jintai Lin
Atmos. Chem. Phys., 21, 18351–18374,Short summary
Simple aromatic compounds (benzene, toluene, xylene) have complex gas-phase chemistry that is inconsistently represented in atmospheric models. We compile recent experimental and theoretical insights to develop a new mechanism for gas-phase aromatic oxidation that is sufficiently compact for use in multiscale models. We compare our new mechanism to chamber experiments and other mechanisms, and implement it in a global model to quantify the impacts of aromatic oxidation on tropospheric chemistry.
Auke J. Visser, Laurens N. Ganzeveld, Ignacio Goded, Maarten C. Krol, Ivan Mammarella, Giovanni Manca, and K. Folkert Boersma
Atmos. Chem. Phys., 21, 18393–18411,Short summary
Dry deposition is an important sink for tropospheric ozone that affects ecosystem carbon uptake, but process understanding remains incomplete. We apply a common deposition representation in atmospheric chemistry models and a multi-layer canopy model to multi-year ozone deposition observations. The multi-layer canopy model performs better on diurnal timescales compared to the common approach, leading to a substantially improved simulation of ozone deposition and vegetation ozone impact metrics.
Amir H. Souri, Kelly Chance, Juseon Bak, Caroline R. Nowlan, Gonzalo González Abad, Yeonjin Jung, David C. Wong, Jingqiu Mao, and Xiong Liu
Atmos. Chem. Phys., 21, 18227–18245,Short summary
The global pandemic is believed to have an impact on emissions of air pollutants such as nitrogen dioxide (NO2) and formaldehyde (HCHO). This study quantifies the changes in the amount of NOx and VOC emissions via state-of-the-art inverse modeling technique using satellite observations during the lockdown 2020 with respect to a baseline over Europe, which in turn, it permits unraveling atmospheric processes being responsible for ozone formation in a less cloudy month.
Paul D. Hamer, Virginie Marécal, Ryan Hossaini, Michel Pirre, Gisèle Krysztofiak, Franziska Ziska, Andreas Engel, Stephan Sala, Timo Keber, Harald Bönisch, Elliot Atlas, Kirstin Krüger, Martyn Chipperfield, Valery Catoire, Azizan A. Samah, Marcel Dorf, Phang Siew Moi, Hans Schlager, and Klaus Pfeilsticker
Atmos. Chem. Phys., 21, 16955–16984,Short summary
Bromoform is a stratospheric ozone-depleting gas released by seaweed and plankton transported to the stratosphere via convection in the tropics. We study the chemical interactions of bromoform and its derivatives within convective clouds using a cloud-scale model and observations. Our findings are that soluble bromine gases are efficiently washed out and removed within the convective clouds and that most bromine is transported vertically to the upper troposphere in the form of bromoform.
Siqi Ma, Daniel Tong, Lok Lamsal, Julian Wang, Xuelei Zhang, Youhua Tang, Rick Saylor, Tianfeng Chai, Pius Lee, Patrick Campbell, Barry Baker, Shobha Kondragunta, Laura Judd, Timothy A. Berkoff, Scott J. Janz, and Ivanka Stajner
Atmos. Chem. Phys., 21, 16531–16553,Short summary
Predicting high ozone gets more challenging as urban emissions decrease. How can different techniques be used to foretell the quality of air to better protect human health? We tested four techniques with the CMAQ model against observations during a field campaign over New York City. The new system proves to better predict the magnitude and timing of high ozone. These approaches can be extended to other regions to improve the predictability of high-O3 episodes in contemporary urban environments.
Mark F. Lunt, Alistair J. Manning, Grant Allen, Tim Arnold, Stéphane J.-B. Bauguitte, Hartmut Boesch, Anita L. Ganesan, Aoife Grant, Carole Helfter, Eiko Nemitz, Simon J. O'Doherty, Paul I. Palmer, Joseph R. Pitt, Chris Rennick, Daniel Say, Kieran M. Stanley, Ann R. Stavert, Dickon Young, and Matt Rigby
Atmos. Chem. Phys., 21, 16257–16276,Short summary
We present an evaluation of the UK's methane emissions between 2013 and 2020 using a network of tall tower measurement sites. We find emissions that are consistent in both magnitude and trend with the UK's reported emissions, with a declining trend driven by a decrease in emissions from England. The impact of various components of the modelling set-up on these findings are explored through a number of sensitivity studies.
Wendong Ge, Junfeng Liu, Kan Yi, Jiayu Xu, Yizhou Zhang, Xiurong Hu, Jianmin Ma, Xuejun Wang, Yi Wan, Jianying Hu, Zhaobin Zhang, Xilong Wang, and Shu Tao
Atmos. Chem. Phys., 21, 16093–16120,Short summary
Compared with the observations, the results incorporating detailed cloud aqueous-phase chemistry greatly reduced SO2 overestimation. The biases in annual simulated SO2 concentrations (or mixing ratios) decreased by 46 %, 41 %, and 22 % in Europe, the USA, and China, respectively. Fe chemistry and HOx chemistry contributed more to SO2 oxidation than N chemistry. Higher concentrations of soluble Fe and higher pH values could further enhance the oxidation capacity.
Stefanie Falk, Ane V. Vollsnes, Aud B. Eriksen, Frode Stordal, and Terje Koren Berntsen
Atmos. Chem. Phys., 21, 15647–15661,Short summary
We evaluate regional and global models for ozone modeling and damage risk mapping of vegetation over subarctic Europe. Our analysis suggests that low-resolution global models do not reproduce the observed ozone seasonal cycle at ground level, underestimating ozone by 30–50 %. High-resolution regional models capture the seasonal cycle well, still underestimating ozone by up to 20 %. Our proposed gap-filling method for site observations shows a 76 % accuracy compared to the regional model (80 %).
Zhe Peng, Julia Lee-Taylor, Harald Stark, John J. Orlando, Bernard Aumont, and Jose L. Jimenez
Atmos. Chem. Phys., 21, 14649–14669,Short summary
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.
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,Short summary
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.
Bharat Rastogi, John B. Miller, Micheal Trudeau, Arlyn E. Andrews, Lei Hu, Marikate Mountain, Thomas Nehrkorn, Bianca Baier, Kathryn McKain, John Mund, Kaiyu Guan, and Caroline B. Alden
Atmos. Chem. Phys., 21, 14385–14401,Short summary
Predicting Earth's climate is difficult, partly due to uncertainty in forecasting how much CO2 can be removed by oceans and plants, because we cannot measure these exchanges directly on large scales. Satellites such as NASA's OCO-2 can provide part of the needed information, but data need to be highly precise and accurate. We evaluate these data and find small biases in certain months that are similar to the signals of interest. We argue that continued improvement of these data is necessary.
Christopher D. Holmes
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Cloud water and ice enable reactions that lead to acid rain and alter atmospheric oxidants, among other impacts. This work develops and evaluates an efficient method of simulating cloud chemistry within global atmospheric models in order to better understand the role of clouds in atmospheric chemistry.
Xuan Wang, Daniel J. Jacob, William Downs, Shuting Zhai, Lei Zhu, Viral Shah, Christopher D. Holmes, Tomás Sherwen, Becky Alexander, Mathew J. Evans, Sebastian D. Eastham, J. Andrew Neuman, Patrick R. Veres, Theodore K. Koenig, Rainer Volkamer, L. Gregory Huey, Thomas J. Bannan, Carl J. Percival, Ben H. Lee, and Joel A. Thornton
Atmos. Chem. Phys., 21, 13973–13996,Short summary
Halogen radicals have a broad range of implications for tropospheric chemistry, air quality, and climate. We present a new mechanistic description and comprehensive simulation of tropospheric halogens in a global 3-D model and compare the model results with surface and aircraft measurements. We find that halogen chemistry decreases the global tropospheric burden of ozone by 11 %, NOx by 6 %, and OH by 4 %.
Volker Matthias, Markus Quante, Jan A. Arndt, Ronny Badeke, Lea Fink, Ronny Petrik, Josefine Feldner, Daniel Schwarzkopf, Eliza-Maria Link, Martin O. P. Ramacher, and Ralf Wedemann
Atmos. Chem. Phys., 21, 13931–13971,Short summary
COVID-19 lockdown measures in spring 2020 led to cleaner air in central Europe. Densely populated areas benefitted mainly from largely reduced NO2 concentrations, while rural areas experienced lower reductions in NO2 but also lower ozone concentrations. Very low particulate matter (PM) concentrations in parts of Europe were not an effect of lockdown measures. Model simulations show that modified weather conditions are more significant for ozone and PM than severe traffic emission reductions.
Hao Guo, Clare M. Flynn, Michael J. Prather, Sarah A. Strode, Stephen D. Steenrod, Louisa Emmons, Forrest Lacey, Jean-Francois Lamarque, Arlene M. Fiore, Gus Correa, Lee T. Murray, Glenn M. Wolfe, Jason M. St. Clair, Michelle Kim, John Crounse, Glenn Diskin, Joshua DiGangi, Bruce C. Daube, Roisin Commane, Kathryn McKain, Jeff Peischl, Thomas B. Ryerson, Chelsea Thompson, Thomas F. Hanisco, Donald Blake, Nicola J. Blake, Eric C. Apel, Rebecca S. Hornbrook, James W. Elkins, Eric J. Hintsa, Fred L. Moore, and Steven Wofsy
Atmos. Chem. Phys., 21, 13729–13746,Short summary
The NASA Atmospheric Tomography (ATom) mission built a climatology of the chemical composition of tropospheric air parcels throughout the middle of the Pacific and Atlantic oceans. The level of detail allows us to reconstruct the photochemical budgets of O3 and CH4 over these vast, remote regions. We find that most of the chemical heterogeneity is captured at the resolution used in current global chemistry models and that the majority of reactivity occurs in the
hottest20 % of parcels.
Ziwei Mo, Ru Cui, Bin Yuan, Huihua Cai, Brian C. McDonald, Meng Li, Junyu Zheng, and Min Shao
Atmos. Chem. Phys., 21, 13655–13666,Short summary
There is a lack of detailed understanding of NMVOC emissions from the use of volatile chemical products (VCPs) in China. This study used a mass balance method to compile a long-term emission inventory for solvent use (including coatings, adhesives, inks, pesticides, cleaners and personal care products) in China during 2000–2017. The striking growth and recent trend of solvent use NMVOC emissions can give important implications for air quality modeling and NMVOC control strategies in China.
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,Short summary
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.
Appel, K. W., Gilliland, A. B., Sarwar, G., and Gilliam, R. C.: Evaluation of the Community Multiscale Air Quality (CMAQ) model version 4.5: Sensitivities impacting model performance, Part I-Ozone, Atmos. Environ., 41, 9603–9615, 2007.
Appel, K. W., Pouliot, G., Simon, H., Sarwar, G., Pye, H. O. T., Napelenok, S., Akhtar, F., Roselle, S.J.: Evaluation of dust and trace metal estimates from the Community Multiscale Air Quality (CMAQ) model version 5.0, Geosci. Model Dev. Discuss., 6, 1859-1899, https://doi.org/10.5194/gmdd-6-1859-2013, 2013.
Arnold, J. R., Dennis, R. L., and Tonnesen, G. S.: Diagnostic Evaluation of Numerical Air Quality Models with Specialized Ambient Observations: Testing the Community Multiscale Air Quality Modeling System (CMAQ) at Selected SOS 95 Ground Sites, Atmos. Environ., 37, 1185–1198, 2003.
Arnold, J. R. Dennis, R. L.: Testing CMAQ chemistry sensitivities in base case and emissions control runs at SEARCH and SOS99 surface sites in the southeastern US, Atmos. Environ., 40, 5027–5040, 2006.
Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G.,Jenkin, M. E., Kerr, J. A., Rossi, M. J., and Troe, J.: Summary of evaluated kinetic and photochemical data for atmospheric chemistry – IUPAC subcommittee on gas kinetic data evaluation for atmospheric chemistry, available at: http://www.iupac-kinetic.ch.cam.ac.uk/index.html, last access: 8 December 2005.
Bey, I., Jacob, D. J., Yantosca, R. M., Logan, J. A., Field, B. D., Fiore, A. M., Li, Q., Liu, H. Y., Mickley, L. J., and Schultz, M. G.: Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23073–23096, 2001.
Binkowski, F. S. and Roselle, S. J.: Community Multiscale Air Quality (CMAQ) model aerosol component, I: Model description, J. Geophys. Res., 108, 4183, https://doi.org/10.1029/2001JD001409, 2003.
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