A modeling study of the impact of heterogeneous reactions on mineral aerosol surfaces on tropospheric chemistry over East Asia

Abstract. The impact of six heterogeneous gas–aerosol uptake reactions on tropospheric ozone and nitrogen species was studied using two chemical transport models, the Meteorological Synthesizing Centre-West of the European Monitoring and Evaluation Programme (EMEP MSC-W) and the European Centre Hamburg general circulation model combined with versions of the Hamburg Aerosol Model and Model for Ozone and Related chemical Tracers (ECHAM-HAMMOZ). Species undergoing heterogeneous reactions in both models include N2O5, NO3, NO2, O3, HNO3, and HO2. Since heterogeneous reactions take place at the aerosol surface area, the modelled surface area density (Sa) of both models was compared to a satellite product retrieving the surface area. This comparison shows a good agreement in global pattern and especially the capability of both models to capture the extreme aerosol loadings in east Asia. The impact of the heterogeneous reactions was evaluated by the simulation of a reference run containing all heterogeneous reactions and several sensitivity runs. One reaction was turned off in each sensitivity run to compare it with the reference run. The analysis of the sensitivity runs confirms that the globally most important heterogeneous reaction is the one of N2O5. Nevertheless, NO2, HNO3, and HO2 heterogeneous reactions gain relevance particularly in east Asia due to the presence of high NOx concentrations and high Sa in the same region. The heterogeneous reaction of O3 itself on dust is of minor relevance compared to the other heterogeneous reactions. The impacts of the N2O5 reactions show strong seasonal variations, with the biggest impacts on O3 in springtime when photochemical reactions are active and N2O5 levels still high. Evaluation of the models with northern hemispheric ozone surface observations yields a better agreement of the models with observations in terms of concentration levels, variability, and temporal correlations at most sites when the heterogeneous reactions are incorporated. Our results are loosely consistent with results from earlier studies, although the magnitude of changes induced by N2O5 reaction is at the low end of estimates, which seems to fit a trend, whereby the more recent the study the lower the impacts of these reactions.

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Ozone Impacts of Gas-Aerosol Uptake in Global Chemistry Transport Models

10.5194/acp-2017-566 ◽

2017 ◽

Cited By ~ 1

Author(s):

Scarlet Stadtler ◽

David Simpson ◽

Sabine Schröder ◽

Domenico Taraborrelli ◽

Andreas Bott ◽

...

Keyword(s):

East Asia ◽

Surface Area ◽

Heterogeneous Reaction ◽

Photochemical Reactions ◽

Heterogeneous Reactions ◽

Transport Models ◽

Global Pattern ◽

Temporal Correlations ◽

The One ◽

The Impact

Abstract. The impact of six heterogeneous gas-aerosol uptake reactions on tropospheric ozone and nitrogen species was studied using two chemical transport models, EMEP MSC-W and ECHAM-HAMMOZ. Species undergoing heterogeneous reactions in both models include N2O5, NO3, NO2, O3, HNO3 and HO2. Since heterogeneous reactions take place at the aerosol surface area, the modeled surface area density Sa of both models was compared to a satellite product retrieving the surface area. This comparison shows a good agreement in global pattern and especially the capability of both models to capture the extreme aerosol loadings in East Asia. The impact of the heterogeneous reactions was evaluated by the simulation of a reference run containing all heterogeneous reactions and several sensitivity runs. One reaction was turned off in each sensitivity run to compare it with the reference run. The analysis of the sensitivity runs confirms that the globally most important heterogeneous reaction is the one of N2O5. Nevertheless, NO2, HNO3 and HO2 heterogeneous reaction gain relevance particularly in East Asia due to the presence of high NOx concentrations and high Sa in the same region, although ECHAM-HAMMOZ showed much stronger responses than EMEP in this respect. The heterogeneous reaction of O3 itself on dust is of minor relevance compared to the other heterogeneous reactions. The impacts of the N2O5 reactions show strong seasonal variations, with biggest impacts on O3 in spring time when photochemical reactions are active and N2O5 levels still high. Evaluation of the models with northern hemispheric ozone surface observations yields a better agreement of the models with observations in terms of concentration levels, variability, and temporal correlations at most sites when the heterogeneous reactions are incorporated.

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Towards a representation of halogen chemistry within volcanic plumes in a chemistry transport model

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-2581-2014 ◽

2014 ◽

Vol 7 (2) ◽

pp. 2581-2650 ◽

Cited By ~ 4

Author(s):

L. Grellier ◽

V. Marécal ◽

B. Josse ◽

P. D. Hamer ◽

T. J. Roberts ◽

...

Keyword(s):

Transport Model ◽

Computational Cost ◽

Ambient Air ◽

Heterogeneous Reactions ◽

Tropospheric Chemistry ◽

Volcanic Plume ◽

Large Set ◽

Chemistry Transport Model ◽

Volcanic Plumes ◽

The Impact

Abstract. Volcanoes are a known source of halogens to the atmosphere. HBr volcanic emissions lead rapidly to the formation of BrO within volcanic plumes as shown by recent work based on observations and models. BrO, having a longer residence time in the atmosphere than HBr, is expected to have a significant impact on tropospheric chemistry, at least at the local and regional scales. The objective of this paper is to prepare a framework that will allow 3-D modelling of volcanic halogen emissions in order to determine their fate within the volcanic plume and then in the atmosphere at the regional and global scales. This work is based on a 1-D configuration of the chemistry transport model MOCAGE whose low computational cost allows us to perform a large set of sensitivity studies. This paper studies the Etna eruption on the 10 May 2008 that took place just before night time. Adaptations are made to MOCAGE to be able to produce the chemistry occurring within the volcanic plume. A simple sub-grid scale parameterization of the volcanic plume is implemented and tested. The use of this parameterization in a 0.5° × 0.5° configuration (typical regional resolution) has an influence on the partitioning between the various bromine compounds both during the eruption period and also during the night period immediately afterwards. During the day after the eruption, simulations both with and without parameterizations give very similar results that are consistent with the tropospheric column of BrO and SO2 in the volcanic plume derived from GOME-2 observations. Tests have been performed to evaluate the sensitivity of the results to the mixing between ambient air and the magmatic air at very high temperature at the crater vent that modifies the composition of the emission, and in particular the sulphate aerosol content that is key compound in the BrO production. Simulations show that the plume chemistry is not very sensitive to the assumptions used for the mixing parameter (relative quantity of ambient air mixed with magmatic air in the mixture) that is not well known. This is because there is no large change in the compounds limiting/favouring the BrO production in the plume. The impact of the model grid resolution is also tested in view of future 3-D-simulations at the global scale. A dilution of the emitted gases and aerosols is observed when using the typical global resolution (2°) as compared to a typical regional resolution (0.5°), as expected. Taking this into account, the results of the 2° resolution simulations are consistent with the GOME-2 observations. In general the simulations at 2° resolution are less efficient at producing BrO after the emission both with and without the subgrid-scale parameterization. The differences are mainly due to an interaction between concentration effects than stem from using a reduced volume in the 0.5° resolution combined with second order rate kinetics. The last series of tests were on the mean radius assumed for the sulphate aerosols that indirectly impacts the production of BrO by heterogeneous reactions. The simulations show that the BrO production is sensitive to this parameter with a stronger production when smaller aerosols are assumed. These results will be used to guide the implementation of volcanic halogen emissions in the 3-D configuration of MOCAGE.

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Influence of aromatics on tropospheric gas-phase composition

10.5194/acp-2020-461 ◽

2020 ◽

Cited By ~ 1

Author(s):

Domenico Taraborrelli ◽

David Cabrera-Perez ◽

Sara Bacer ◽

Sergey Gromov ◽

Jos Lelieveld ◽

...

Keyword(s):

East Asia ◽

Gas Phase ◽

Atmospheric Chemistry ◽

General Circulation ◽

Anthropogenic Activities ◽

Regional Scale ◽

Circulation Model ◽

Significant Loss ◽

Tropospheric Chemistry ◽

The Impact

Abstract. Aromatics contribute a significant fraction to organic compounds in the troposphere and are mainly emitted by anthropogenic activities and biomass burning. Their oxidation in lab experiments is known to lead to the formation of ozone and aerosol precursors. However, their overall impact on tropospheric composition is uncertain as it depends on transport, multiphase chemistry, and removal processes of the oxidation intermediates. Representation of aromatics in global atmospheric models has been either neglected or highly simplified. Here, we present an assessment of their impact on the gas-phase chemistry, using the general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). We employ a comprehensive kinetic model to represent the oxidation of the following monocyclic aromatics: benzene, toluene, xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde, and lumped higher aromatics that contain more than 9 C atoms. Significant regional changes are identified for several species. For instance, glyoxal increases by 130 % in Europe and 260 % in East Asia, respectively. Large increases in HCHO are also predicted in these regions. In general, the influence of aromatics is particularly evident in areas with high concentrations of NOx, with increases up to 12 % in O3 and 17 % in OH. On a global scale, the estimated net changes are minor when aromatic compounds are included in our model. For instance, the tropospheric burden of CO increases by about 6 %, while the burdens of OH, O3, and NOx (NO + NO2) decrease between 3 % and 9 %. The global mean changes are small, partially because of compensating effects between high- and low-NOx regions. The largest change is predicted for the important aerosol precursor glyoxal, which increases globally by 36 %. In contrast to other studies, the net change in tropospheric ozone is predicted to be negative, −3 % globally. This change is larger in the northern hemisphere where global models usually show positive biases. We find that the reaction with phenoxy radicals is a significant loss for ozone, of the order of 200–300 Tg/yr, which is similar to the estimated ozone loss due to bromine chemistry. Although the net global impact of aromatics is limited, our results indicate that aromatics can strongly influence tropospheric chemistry on a regional scale, most significantly in East Asia. An analysis of the main model uncertainties related to oxidation and emissions suggests that the impact of aromatics may even be significantly larger.

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Impact of dust on tropospheric chemistry over polluted regions: a case study of the Beijing megacity

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-3855-2010 ◽

2010 ◽

Vol 10 (8) ◽

pp. 3855-3873 ◽

Cited By ~ 37

Author(s):

S. Zhu ◽

T. Butler ◽

R. Sander ◽

J. Ma ◽

M. G. Lawrence

Keyword(s):

Oxidation Mechanism ◽

Heterogeneous Reactions ◽

Tropospheric Chemistry ◽

Rate Coefficients ◽

Air Masses ◽

Photolysis Rates ◽

Tropospheric Photochemistry ◽

Quantitative Results ◽

Relative Change ◽

The Impact

Abstract. The box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) is extended by incorporating detailed heterogeneous chemistry occurring on mineral aerosol surfaces. The model is used to investigate the impact of dust on tropospheric photochemistry, when the dust is transported to a polluted region, focusing on the example of Beijing. The impacts of dust via heterogeneous removal of gases are analyzed for different hypothetical transport rates, which are described by four different exchange rate coefficients Kt in the model. Along with the dust, airmasses with trace gas levels characteristic for regions upwind of Beijing are transported with the same rate (Kt). Substantial impacts are found for many gases, including Ox (O3+O(3P)), NOx (NO+NO2) and OH. The Ox daily average mixing ratio decreases due to heterogeneous reactions on dust. The change ranges from −2.5 to −18.4 nmol mol−1, and is larger for faster mixing with upwind air masses (i.e. greater Kt). This translates into a large relative change in Ox, ranging from −44% to −55%, depending on Kt. By assuming an artificial 50% decrease of all photolysis rates, the impacts of dust via perturbation of the photolysis rates in the polluted region are also estimated. Furthermore, the uncertainties in the results due to the uncertainties in the uptake coefficients are evaluated. It is found that for all gases which are heterogeneously removed, the self-removal results in the largest uncertainty (e.g. −49% for O3, −76% for NO2, −47% for HNO3, −92% for HCHO, −64% for CH3OH and −93% for SO2). The heterogeneous removal of NO2 is found to be particularly important, because it results in significant levels of uncertainty not only for itself, but also for OH (340%) and HO2 (365%). Moreover, the heterogeneous removal rates of HCHO and O3 also have farther-reaching effects on the OH concentration (resulting in changes of −55% and 45%, respectively), and the heterogeneous removal of HCHO results in an uncertainty of −38% in the HO2 concentration. The limitations of MECCA due to its missing oxidation mechanism for aromatics and other higher VOC species has also been considered, and shown to be potentially important in the quantitative results, though not likely to change the qualitative results of this study.

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Influence of aromatics on tropospheric gas-phase composition

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-2615-2021 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2615-2636

Author(s):

Domenico Taraborrelli ◽

David Cabrera-Perez ◽

Sara Bacer ◽

Sergey Gromov ◽

Jos Lelieveld ◽

...

Keyword(s):

East Asia ◽

Gas Phase ◽

Atmospheric Chemistry ◽

General Circulation ◽

Anthropogenic Activities ◽

Regional Scale ◽

Circulation Model ◽

Significant Loss ◽

Tropospheric Chemistry ◽

The Impact

Abstract. Aromatics contribute a significant fraction to organic compounds in the troposphere and are mainly emitted by anthropogenic activities and biomass burning. Their oxidation in lab experiments is known to lead to the formation of ozone and aerosol precursors. However, their overall impact on tropospheric composition is uncertain as it depends on transport, multiphase chemistry, and removal processes of the oxidation intermediates. Representation of aromatics in global atmospheric models has been either neglected or highly simplified. Here, we present an assessment of their impact on gas-phase chemistry, using the general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). We employ a comprehensive kinetic model to represent the oxidation of the following monocyclic aromatics: benzene, toluene, xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde, and lumped higher aromatics that contain more than nine C atoms. Significant regional changes are identified for several species. For instance, glyoxal increases by 130 % in Europe and 260 % in East Asia, respectively. Large increases in HCHO are also predicted in these regions. In general, the influence of aromatics is particularly evident in areas with high concentrations of NOx, with increases up to 12 % in O3 and 17 % in OH. On a global scale, the estimated net changes of trace gas levels are minor when aromatic compounds are included in our model. For instance, the tropospheric burden of CO increases by about 6 %, while the burdens of OH, O3, and NOx (NO+NO2) decrease between 3 % and 9 %. The global mean changes are small, partially because of compensating effects between high- and low-NOx regions. The largest change is predicted for the important aerosol precursor glyoxal, which increases globally by 36 %. In contrast to other studies, the net change in tropospheric ozone is predicted to be negative, −3 % globally. This change is larger in the Northern Hemisphere where global models usually show positive biases. We find that the reaction with phenoxy radicals is a significant loss for ozone, on the order of 200–300 Tg yr−1, which is similar to the estimated ozone loss due to bromine chemistry. Although the net global impact of aromatics is limited, our results indicate that aromatics can strongly influence tropospheric chemistry on a regional scale, most significantly in East Asia. An analysis of the main model uncertainties related to oxidation and emissions suggests that the impact of aromatics may even be significantly larger.

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The Impact of the Aqueous Phase Chemistry of HNO4 on Gas Phase Tropospheric Chemistry

Journal of Aerosol Science ◽

10.1016/s0021-8502(21)00128-2 ◽

2001 ◽

Vol 32 ◽

pp. 269-270

Author(s):

J.E. WILLIAMS ◽

F.J. DENTENER ◽

A.R. van den BERG

Keyword(s):

Gas Phase ◽

Aqueous Phase ◽

Tropospheric Chemistry ◽

Phase Chemistry ◽

The Impact

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Hybrid nanofluid flow over a stretched cylinder with the impact of homogeneous–heterogeneous reactions and Cattaneo–Christov heat flux: Series solution and numerical simulation

Heat Transfer ◽

10.1002/htj.22052 ◽

2021 ◽

Author(s):

Anthonysamy John Christopher ◽

Nanjundan Magesh ◽

Ramanahalli Jayadevamurthy Punith Gowda ◽

Rangaswamy Naveen Kumar ◽

Ravikumar Shashikala Varun Kumar

Keyword(s):

Numerical Simulation ◽

Heat Flux ◽

Series Solution ◽

Heterogeneous Reactions ◽

Hybrid Nanofluid ◽

Nanofluid Flow ◽

The Impact

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Reply to T.M. Simbirtseva and S.V. Volkov: Facts Against Fantasies

Problemy Dalnego Vostoka ◽

10.31857/s013128120017086-5 ◽

2021 ◽

pp. 127

Author(s):

Bella Pak

Keyword(s):

East Asia ◽

Scientific Research ◽

Russian Government ◽

New Information ◽

History Of ◽

The Impact ◽

Specific Contribution

This article provides an analysis of scientific research on the life and activities of the first Russian charge d’ affaires and consul general in Korea Karl I. Waeber, shows the specific contribution of scholars to the study of the professional biography of this outstanding diplomat. Despite the fact that the activity of K.I. Weber in Korea is partially reflected in the works of Boris D. Pak and Bella B. Pak on the history of Russo-Korean relations, as well as in several separate articles, the first special monographic work on this topic belongs to the pen of the author of this article. The monographic research focuses on a detailed coverage of the tasks, goals facing Waeber in Korea, the specific forms and conditions for their implementation, the impact he exerts on the course of the Russian government towards Korea; analysis of the most complex international circumstances, against the background of which he made certain decisions. This article contains answers to T.M. Simbirtseva and S.V. Volkov’s critical remarks regarding some of the information and photographic documents given in the work concerning K.I. Waeber and the accusations against the author of the article in connection with the publication in Germany in the summer of 2021 of Dr. S. Braezel's photobook "Pictures of the life of a diplomat between Europe and East Asia: Karl von Waeber (1841-1910)". The author of the article drew attention to some erroneous judgments in the article by T.M. Simbirtseva and S.V. Volkov, formed due to ignorance and bias, analyzed and refuted the most unfounded accusations, clarified the position regarding new information about K.I. Waeber.

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