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1. The Synergetic Reduction of the Condensation Degree of Dissolved Lignin (DL) during the Refining Process of Wheat Straw Biomass Based on the MA/O 3 System.

Author

Chen X, Liu Z, Zhou Z, Li R, Li L, and Cao Y

Subjects
Lignin chemistry, Triticum chemistry, Biomass, Ozone chemistry, Maleates chemistry
Abstract

Lignin, a natural pol2ymer with a complex structure that is difficult to separate, is prone to C-C bond condensation during the separation process. To reduce the condensation of lignin, here, a novel method is proposed for separating the components by using a combination of maleic acid (MA)/ozone (O 3 ) to co-treat wheat straw. The removal of lignin, glucan, and xylan was 38.07 ± 0.2%, 31.44 ± 0.1%, and 71.98 ± 0.1%, respectively, under the conditions of ball-milling of wheat straw for 6 h, reaction temperature of 60 °C, and O 3 holding time of 9 min. Lignin-rich solutions were collected to extract the dissolved lignin (DL) after washing the treated samples. The DL obtained under MA/O 3 conditions had a carboxyl group (-COOH) content of 2.96 mmol/g. The carboxyl group of MA underwent esterification with the hydroxyl group (-OH) at the γ position of lignin and O 3 reacted on the positions of the lignin side chain or the phenolic ring, resulting in a break in the side chain and the opening of the phenolic ring to introduce the carboxyl group. The 2D-HSQC-NMR results revealed that the phenolic ring-opening reaction of lignin in the presence of O 3 was essentially free of β-β and β-5 condensation bonds.

Published
2024
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2. Controlling unequal surface energy results caused by test liquids: the case of UV/O3 Treated PET.

Author

Altay BN, Fleming PD, Rahman MA, Pekarovicova A, Myers B, Aydemir C, and Karademir A

Subjects
Adsorption, Surface Properties, Wettability, Ozone, Polyethylene Terephthalates chemistry
Abstract

Ultraviolet/ozone (UV/O 3 ) treatment has been reported to be an effective method to modify properties such as wettability, adhesion or adsorption of plastic surfaces. The change in the surface is measured by contact angle analysis, which employs liquids and their surface tensions (ST) to estimate the surface energy (SE). We found two different practices in the scientific community: (1) the majority of researchers adopted the ST value of liquids from the literature, while (2) other researchers conducted real-time measurements in the lab under ambient conditions prior to SE estimation. To the best of our knowledge, there is no study that compares the difference between the two practices. One study was found to show different SE methods generating unequal SE values for the same substrate. However, there was no definitive conclusion backed by general thermodynamics rules. In this study, we presented (1) a statistical significance test that showed the literature and experimental ST values are significantly different, and studied (2) the effect of different liquid pairs on the SE estimation for UV/O 3 treated poly(ethylene terephthalate) (PET) substrate. Modification techniques such as atmospheric pressure plasma or chemical modification were studied previously to examine PET's wettability and the SE. The UV/O 3 treatment was studied to improve adhesion and to modify its chemical properties for adsorption. In contrast, we studied (3) the effect of UV/O 3 on wettability at different timeframes and addressed (4) how to control unequal SE based on a method that was refined on a rigorous thermodynamic three-phase system. It must be noted that this method can be generalized to other types of solid surfaces to estimate thermodynamically self-consistent SE values. This work also provides (5) a web-based calculator that complements computational findings available to the readership in the data availability section., (© 2022. The Author(s).)

Published
2022
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3. Mechanistic and Kinetic Investigations on the Ozonolysis of Biomass Burning Products: Guaiacol, Syringol and Creosol.

Author

Chen X, Sun Y, Qi Y, Liu L, Xu F, and Zhao Y

Subjects
Atmosphere chemistry, Kinetics, Molecular Conformation, Pyrogallol chemistry, Biomass, Cresols chemistry, Guaiacol chemistry, Ozone chemistry, Pyrogallol analogs & derivatives
Abstract

The lignin pyrolysis products generated by biomass combustion make an essential contribution to the formation of secondary organic aerosols (SOAs). The ozone-initiated oxidation of guaiacol, syringol and creosol, major constituents of biomass burning, were investigated theoretically by using the density functional theory (DFT) method at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. Six primary addition reaction pathways and further decomposition routes with corresponding thermodynamic values were proposed. The Criegee intermediates can be excited by small molecules, such as NO x , H 2 O in the atmosphere, and would further proceed via self-decomposition or isomerization. The most predominant product for ozonation of guaiacol is the monomethyl muconate (P1). At 295 K and atmospheric pressure, the rate constant is 1.10 × 10 -19 cm 3 molecule -1 s -1 , which is lies a factor of 4 smaller than the previous experimental study. The branching ratios of the six channels are calculated based on corresponding rate coefficient. The present work mainly provides a more comprehensive and detailed theoretical research on the ozonation of methoxyphenol, which aspires to offer novel insights and reference for future experimental and theoretical work and control techniques of SOAs caused by lignin pyrolysis products.

Published
2019
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4. Effect of incorporation of ozone prior to ECF bleaching on pulp, paper and effluent quality.

Author

Kaur D, Bhardwaj NK, and Lohchab RK

Subjects
Chlorine, Industrial Waste, Paper, Wastewater, Chlorophenols, Ozone
Abstract

The pulp and paper industry is highly dependent on forest and water resources. It has more concerns on fair utilization of these resources and their conservation for its further expansion. Present study emphasizes on the use of rice straw (agro waste) in papermaking to protect wood based resources. It further deals with ozone bleaching (Z) prior to elemental chlorine free bleaching that proved to be significant in terms of reducing the effluent load specially the reduction in toxic, recalcitrant and carcinogenic compounds. Z based sequences resulted in pulp brightness of ∼85% that was 3.6% higher than the elemental chlorine free bleaching. Bleached pulps of Z based sequences were found to be having better strength properties than elemental chlorine based sequence and thus may be adopted as improved bleaching technology. The analysis of handsheets prepared after pulp bleaching was performed using X-Ray diffraction, ATR-FTIR and SEM. Incorporating ozone stage resulted in marked reduction of 58% and 63% in total solids in bleaching wastewater. Reduction of more than 80% in BOD, COD and adsorbable organic halides was achieved in Z based bleaching in comparison to chlorine bleaching. The amount of chlorophenols, guaiacols, catechols, vanillins and syringols became negligible (approx. 90% reduction) in effluents of Z based bleaching sequences. The chlorine dioxide followed by peroxide bleaching after Z stage was found to be the most promising to reduce the effluent load., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Published
2019
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5. Bulky DNA adducts, 4-aminobiphenyl-haemoglobin adducts and diet in the European Prospective Investigation into Cancer and Nutrition (EPIC) prospective study

Author

Carmen Martinez, Petra H.M. Peeters, Merethe Kumle, Paolo Vineis, Armelle Munnia, Seymour Garte, Bas Bueno-de-Mesquita, Emmanuelle Gormally, Ole Raaschou-Nielsen, Antonio Agudo, Giuseppe Matullo, Bengt Järvholm, Françoise Clavel-Chapelon, José Ramón Quirós, Göran Berglund, Marco Peluso, Alison M. Dunning, Rosario Tumino, Alessandro Colombi, Salvatore Panico, Timothy J. Key, Luisa Airoldi, Elio Riboli, S Bingham, Fabrizio Veglia, Rudolf Kaaks, Antonia Trichopoulou, Aurelio Barricarte, Vittorio Krogh, Christian Malaveille, Nicholas E. Day, Kim Overvad, Rodolfo Saracci, Herman Autrup, María José Tormo, Domenico Palli, J. Linseisen, Heiner Boeing, Miren Dorronsoro, Faculteit Medische Wetenschappen/UMCG, Peluso, M, Airoldi, L, Munnia, A, Colombi, A, Veglia, F, Autrup, H, Dunning, A, Garte, S, Gormally, E, Malaveille, C, Matullo, G, Overvad, K, Raaschou Nielsen, O, Clavel Chapelon, F, Linseisen, J, Boeing, H, Trichopoulou, A, Palli, D, Krogh, V, Tumino, R, Panico, Salvatore, Bueno De Mesquita, Bh, Peeters, Ph, Kumle, M, Agudo, A, Martinez, C, Dorronsoro, M, Barricarte, A, Tormo, Mj, Quiros, Jr, Berglund, G, Jarvholm, B, Day, Ne, Key, Tj, Saracci, R, Kaaks, R, Riboli, E, Bingham, S, Vineis, P., [Peluso,M, Munnia, A] Cancer Risk Factor Branch, Analytical and Biomolecular Cytology Unit, CSPO-Scientific Institute of Tuscany, Florence, Italy. [Airoldi,L, Colombi,A] Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. [Veglia, F, Matullo,G] ISI Foundation, Turin, Italy. [Autrup,H] Department of Environmental and Occupational Medicine, Aarhus, Denmark. [Dunning, A] Department of Oncology, University of Cambridge, Cambridge, UK. [Garte,S] Genetics Research Institute, Milan, Italy. [Gormally,E, Malaveille,C] International Agency for Research on Cancer, Lyon, France. [Overhad,K] Department of Clinical Epidemiology, Aalborg Hospital, Aarhus University Hospital, Aalborg, Denmark. [Raaschou-Nielsen,O] Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. [Clavel-Chapelon,F] INSERM (Institut National de la Sante´ et de la Recherche Me´dicale), ERI 20, EA 4045, and Institut Gustave Roussy, Villejuif, F-94805, France. [Linseisen,J] Division of Clinical Epidemiology, Deutsches Krebsforschungszentrum, Heidelberg, German. [Boeing,H] German Institute of Human Nutrition, Potsdam-Rehbu¨cke, Germany. [Trichopoulou,A] Department of Hygiene and Epidemiology, Medical School, University of Athens, Athens, Greece. [Palli,D] Molecular and Nutritional Epidemiology Unit, CSPO-Scientific Institute of Cancer Prevention Tuscany Region, Florence, Italy. [Krogh,V] Department of Epidemiology, National Cancer Institute, Milan, Italy. [Tumino,R] Cancer Registry, Azienda Ospedaliera ‘Civile MP Arezzo’, Ragusa, Ital. [Panico,S] Dipartimento di Medicina Clinica e Sperimentale, Universita` Federico II, Naples, Italy. [Bueno-De-Mesquita,BH] Centre for Nutrition and Health, National Institute for Public Health and the Environment, Bilthoven, The Netherland. [Peeters,PH] Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht, The Netherlands. [Kumle,M] Institute of Community Medicine, University of Tromso, Tromso, Norway. [Agudo,A] Department of Epidemiology, Catalan Institute of Oncology, Barcelona, Spain. [Martinez,C] Andalusian School of Public Health, Granada, Spain. [Dorronsoro,M] Department of Public Health of Guipuzkoa, San Sebastian, Spain. [Barricarte,A] Public Health Institute, Navarra, Spain. [Tormo,MJ] Epidemiology Department, Murcia Health Council, Murcia, Spain. Quiros, JR] Direccio´n General de Salud Pu´blica, Consejerı´a de Salud y Servicios Sanitarios Asturias, Oviedo, Spain. [Berglund,G] Malmo¨ Diet and Cancer Study, Lund University, Malmo¨, Sweden. [Jarvholm,G] Department of Nutritional Research, University of Umea˚, Umea˚ , Sweden. [Day,ND, Bingham,S] MRC Dunn Human Nutrition Unit, Cambridge University, UK. [Key,TJ].Cancer Research UK Epidemiology Unit, University of Oxford, Oxford, UK. [Saracci,R] IFC National Research Council, Pisa, Italy. [Kaas,R] Division of Epidemiology, DKFZ Heidelberg, Germany. [Riboli,E] Imperial College London, London, UK. [Vineis,P] University of Turin, Turin, Italy. Department of Epidemiology and Public Health, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK, This paper was made possible by a grant of the European Community (5th Framework Programme) to P. V. (grant QLK4–CT–1999–00 927) and a grant of the Compagnia di San Paolo to the ISI Foundation. All authors are independent from funders. Mortality data for the Netherlands were obtained from Statistics Netherlands. Also, the work described in the paper was carried out with the financial support of: Europe Against Cancer Program of the European Commission (SANCO), ISCIII, Red de Centros RCESP, C03/09, Deutsche Krebshilfe, Deutsches Krebsforschungszentrum, German Federal Ministry of Education and Research, Danish Cancer Society, Health Research Fund (FIS) of the Spanish Ministry of Health, Spanish Regional Governments of Andalucia, Asturias, Basque Country, Murcia and Navarra, Cancer Research UK, Medical Research Council, UK, Stroke Association, UK, British Heart Foundation, Department of Health, UK, Food Standards Agency, UK, Wellcome Trust, UK, Greek Ministry of Health, Greek Ministry of Education, Italian Association for Research on Cancer (AIRC), Italian National Research Council, Dutch Ministry of Public Health, Welfare and Sports, World Cancer Research Fund, Swedish Cancer Society, Swedish Scientific Council, Regional Government of Ska°ne, Sweden, Norwegian Cancer Society, and Research Council of Norway.

Subjects
Dietary Fiber, Male, Aflatoxin, Erythrocytes, Chemicals and Drugs::Amino Acids, Peptides, and Proteins::Proteins::Blood Proteins::Hemoglobins [Medical Subject Headings], medicine.medical_treatment, air pollution, RESISTANT STARCH, Medicine (miscellaneous), GUIDELINES, Carcinógenos, Body Mass Index, COLORECTAL-CANCER, Food group, chemistry.chemical_compound, Hemoglobins, Vegetables, Chemicals and Drugs::Chemical Actions and Uses::Toxic Actions::Environmental Pollutants::Air Pollutants [Medical Subject Headings], Leukocytes, Aductos de ADN, Nutritional Physiological Phenomena, Food science, Prospective Studies, RISK, DNA adducts, Haemoglobin adducts, Non-smokers, Fibre intake, Air pollution, Publication Characteristics::Study Characteristics::Multicenter Study [Medical Subject Headings], Air Pollutants, Nutrition and Dietetics, Chemistry, Technology, Industry, Agriculture::Food and Beverages::Food::Dietary Fiber [Medical Subject Headings], Chemicals and Drugs::Chemical Actions and Uses::Toxic Actions::Noxae::Carcinogens [Medical Subject Headings], COLON-CANCER, Phenomena and Processes::Genetic Phenomena::Genetic Processes::DNA Damage::DNA Adducts [Medical Subject Headings], Fabaceae, Middle Aged, fibre intake, European Prospective Investigation into Cancer and Nutrition, Europe, Biochemistry, 4-Aminobiphenyl, Colonic Neoplasms, Hemoglobinas, Female, SMOKERS, Alcohol Drinking, BLADDER-CANCER, European Prospective Investigation into Cancer and Nutrition (EPIC), haemoglobin adducts, non-smokers, RATS, POLYCYCLIC AROMATIC-HYDROCARBONS, Ozone, LUNG-CANCER, DNA adduct, medicine, Humans, Contaminantes del aire, ddc:610, Carcinogen, Aged, Estudio multicéntrico, Vitamin E, Fruit, Multivariate Analysis, Fibras en la dieta, Carcinogens, Biomarkers, Food contaminant
Abstract

Udgivelsesdato: 2008-Feb-14 In contrast to some extensively examined food mutagens, for example, aflatoxins, N-nitrosamines and heterocyclic amines, some other food contaminants, in particular polycyclic aromatic hydrocarbons (PAH) and other aromatic compounds, have received less attention. Therefore, exploring the relationships between dietary habits and the levels of biomarkers related to exposure to aromatic compounds is highly relevant. We have investigated in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort the association between dietary items (food groups and nutrients) and aromatic DNA adducts and 4-aminobiphenyl-Hb adducts. Both types of adducts are biomarkers of carcinogen exposure and possibly of cancer risk, and were measured, respectively, in leucocytes and erythrocytes of 1086 (DNA adducts) and 190 (Hb adducts) non-smokers. An inverse, statistically significant, association has been found between DNA adduct levels and dietary fibre intake (P = 0.02), vitamin E (P = 0.04) and alcohol (P = 0.03) but not with other nutrients or food groups. Also, an inverse association between fibre and fruit intake, and BMI and 4-aminobiphenyl-Hb adducts (P = 0.03, 0.04, and 0.03 respectively) was observed. After multivariate regression analysis these inverse correlations remained statistically significant, except for the correlation adducts v. fruit intake. The present study suggests that fibre intake in the usual range can modify the level of DNA or Hb aromatic adducts, but such role seems to be quantitatively modest. Fibres could reduce the formation of DNA adducts in different manners, by diluting potential food mutagens and carcinogens in the gastrointestinal tract, by speeding their transit through the colon and by binding carcinogenic substances.

Published
2008

6. Recent ozone trends in the Chinese free troposphere: role of the local emission reductions and meteorology

Author

G. Dufour, D. Hauglustaine, Y. Zhang, M. Eremenko, Y. Cohen, A. Gaudel, G. Siour, M. Lachatre, A. Bense, B. Bessagnet, J. Cuesta, J. Ziemke, V. Thouret, B. Zheng, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), NASA Goddard Space Flight Center (GSFC), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Tsinghua University [Beijing] (THU), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), GD managed the study from its conception,the analysis of data, the preparation of the paper, and the fundingacquisition, ANR-15-CE04-0005,PolEASIA,Pollution en Asie de l'Est: vers une meilleure prévision de la qualité de l'air et une meilleure évaluation de son impact(2015), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Ozone Monitoring Instrument, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Ozone, 010504 meteorology & atmospheric sciences, Physics, QC1-999, 010501 environmental sciences, Infrared atmospheric sounding interferometer, Atmospheric sciences, 01 natural sciences, Microwave Limb Sounder, Troposphere, chemistry.chemical_compound, Chemistry, chemistry, 13. Climate action, Environmental science, Tropospheric ozone, Emission inventory, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, QD1-999, NOx, 0105 earth and related environmental sciences
Abstract

Free tropospheric ozone (O3) trends in the Central East China (CEC) and export regions are investigated for 2008–2017 using the IASI (Infrared Atmospheric Sounding Interferometer) O3 observations and the LMDZ-OR-INCA model simulations, including the most recent Chinese emission inventory. The observed and modelled trends in the CEC region are −0.07 ± 0.02 and −0.08 ± 0.02 DU yr−1, respectively, for the lower free troposphere (3–6 km column) and −0.05 ± 0.02 and −0.06 ± 0.02 DU yr−1, respectively, for the upper free troposphere (6–9 km column). The statistical p value is smaller to 0.01 for all the derived trends. A good agreement between the observations and the model is also observed in the region, including the Korean Peninsula and Japan and corresponding to the region of pollution export from China. Based on sensitivity studies conducted with the model, we evaluate, at 60 % and 52 %, the contribution of the Chinese anthropogenic emissions to the trend in the lower and upper free troposphere, respectively. The second main contribution to the trend is the meteorological variability (34 % and 50 %, respectively). These results suggest that the reduction in NOx anthropogenic emissions that has occurred since 2013 in China led to a decrease in ozone in the Chinese free troposphere, contrary to the increase in ozone at the surface. We designed some tests to compare the trends derived by the IASI observations and the model to independent measurements, such as the In-service Aircraft for a Global Observing System (IAGOS) or other satellite measurements (Ozone Monitoring Instrument (OMI)/Microwave Limb Sounder (MLS)). These comparisons do not confirm the O3 decrease and stress the difficulty in analysing short-term trends using multiple data sets with various sampling and the risk of overinterpreting the results.

Published
2021