Oxidation of low-molecular-weight organic compounds in cloud droplets: development of the Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC) in CAABA/MECCA (version 4.5.0)

Rosanka, Simon; Sander, R.; Wahner, Andreas; Taraborrelli, Domenico

doi:10.5194/gmd-14-4103-2021

Cited by 16 publications

(27 citation statements)

References 60 publications

(114 reference statements)

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“…This mechanism can be considered the current standard mechanism used in EMAC. The last aqueousphase mechanism is the complex OVOC oxidation scheme JAMOC developed in our companion paper by Rosanka et al (2021). This mechanism is based on the box-model mechanism Cloud Explicit Physico-chemical Scheme (CLEPS 1.0; Mouchel-Vallon et al, 2017).…”

Section: Aqueous Phasementioning

confidence: 99%

“…This mechanism is based on the box-model mechanism Cloud Explicit Physico-chemical Scheme (CLEPS 1.0; Mouchel-Vallon et al, 2017). In order to make it applicable for global models, Rosanka et al (2021) reduced the number of aqueous-phase species to a selection containing up to 4 carbon atoms. JAMOC represents the photo-oxidation of all species containing 1 and 2 carbon atoms represented in CLEPS but limits the photo-oxidation of species with 3 or 4 carbon atoms to the major products from C 5 H 8 oxidation (i.e.…”

Section: Aqueous Phasementioning

confidence: 99%

“…Still, the phase transfer of soluble species containing up to 10 carbon atoms is represented in JAMOC. In addition to CLEPS, Rosanka et al (2021) extended JAMOC by (1) simulating hydration and dehydration explicitly; (2) taking the oligomerisation of formaldehyde, glyoxal, and methylglyoxal into account; (3) adding further aqueous-phase photolysis reactions; and (4) considering the gas-phase photo-oxidation of new outgassed species. Overall, JAMOC represents the phase transfer of 350 species, 43 equilibria (acid-base and hydration), and more than 280 photo-oxidation reactions.…”

Section: Aqueous Phasementioning

confidence: 99%

“…Overall, JAMOC represents the phase transfer of 350 species, 43 equilibria (acid-base and hydration), and more than 280 photo-oxidation reactions. A complete description of JAMOC, including a list of all reactions, is available in Rosanka et al (2021). Even though Fenton's chemistry is an in-cloud source of OH (aq) , this chemistry is not considered in this study (switched off in JAMOC) due to missing global iron (Fe) distributions and emissions in EMAC.…”

Section: Aqueous Phasementioning

confidence: 99%

“…Thus, it is expected that global atmospheric models underestimate clouds as O 3 sinks. In order to make a detailed in-cloud OVOC oxidation scheme readily available for box as well as for regional and global simulations that is affordable with modern supercomputing facilities, we have developed the Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC) and implemented it into the atmospheric chemistry mechanism Module Efficiently Calculating the Chemistry of the Atmosphere (MECCA) in our companion paper by Rosanka et al (2021). In JAMOC, the phase transfer of species containing up to 10 carbon atoms is taken into account, and a selection of species containing up to 4 carbon atoms is considered to react in the aqueous phase, resulting in more than 1000 reactions.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Rosanka¹,

Sander²,

Franco³

et al. 2020

Preprint

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Abstract. In liquid cloud droplets, superoxide anion (O−2(aq)) is known to quickly consume ozone (O3(aq)), which is relatively insoluble. The significance of this reaction as tropospheric O3 sink is sensitive to the abundance of O−2(aq) and therefore to the production of its main precursor, hydroperoxyl radical (HO2(aq)). The aqueous-phase oxidation of oxygenated volatile organic compounds (OVOCs) is the major source of HO2(aq) in cloud droplets. Hence, the lack of explicit aqueous-phase chemical kinetics in global atmospheric models leads to a general underestimation of clouds as O3 sinks. In this study, the importance of in-cloud OVOC oxidation for tropospheric composition is assessed by using the Chemistry As A Boxmodel Application (CAABA) and the global atmospheric model ECHAM/MESSy (EMAC), which are both capable of explicitly representing the relevant chemical transformations. For this analysis, three different in-cloud oxidation mechanisms are employed: (1) one including the basic oxidation of SO2(aq) via O3(aq) and H2O2(aq), which thus represents the capabilities of most global models, (2) the more advanced standard EMAC mechanism, which includes inorganic chemistry and simplified degradation of methane oxidation products, and (3) the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC). By using EMAC, the global impact of each mechanism is assessed focusing mainly on tropospheric volatile organic compounds (VOCs), HOx (HOx = OH+HO2), and O3. This is achieved by performing a detailed HOx and O3 budget analysis in the gas- and aqueous-phase. The resulting changes are evaluated against O3 and methanol (CH3OH) satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) for 2015. In general, the explicit in-cloud oxidation leads to an overall reduction of predicted OVOCs levels, and reduces EMAC's overestimation of some OVOCs in the tropics. The in-cloud OVOC oxidation shifts the HO2 production from the gas- to the aqueous-phase. As a result, the O3 budget is perturbed with scavenging being enhanced and the gas-phase chemical losses being reduced. With the simplified in-cloud chemistry, about 13 Tg a−1 of O3 are scavenged, which increases to 336 Tg a−1 when JAMOC is used. The highest O3 reduction of 12 % is predicted in the upper troposphere/lower stratosphere (UTLS). These changes in the free troposphere significantly reduce the modelled tropospheric ozone columns, which are known to be generally overestimated by EMAC and other global atmospheric models.

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Section: Aqueous Phasementioning

confidence: 99%

Section: Aqueous Phasementioning

confidence: 99%

Section: Aqueous Phasementioning

confidence: 99%

Section: Aqueous Phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Rosanka¹,

Sander²,

Franco³

et al. 2020

Preprint

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Carbonyl Compounds Regulate Atmospheric Oxidation Capacity and Particulate Sulfur Chemistry in the Coastal Atmosphere

Zhao,

Shen,

Zhang

et al. 2024

Environ. Sci. Technol.

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Carbonyl compounds play a crucial role in the formation of ozone (O 3 ) and secondary aerosols, with recent studies particularly highlighting formaldehyde (HCHO) as a significant contributor to the missing particulate sulfur. However, evaluations based on field observations are limited, especially in clean marine environments. Utilizing observation data from a coastal mountain site in May 2021 in Qingdao, northern China, we reveal the important regulating effect of carbonyls in atmospheric oxidation capacity and particulate sulfur chemistry using detailed chemical box models. Photolysis of gaseous carbonyls accounted for >90% and >60% of the primary sources of HO 2 and RO 2 , respectively, contributing 38% of net O 3 production. Notably, HCHO alone constituted 80% of the primary HO 2 and 15% of net O 3 production. Using a multiphase model with updated HCHO-related chemistry, we determine that HCHO chemistry can account for up to 30% of total particulate sulfur (the sum of hydroxymethanesulfonate and sulfate) and address more than one-third of the simulated sulfate gap. The emission-based multiphase model indicates that the HCHO-related pathway remains significant and can account for 20% of the particulate sulfur under clean marine conditions. These findings underscore the importance of carbonyls, particularly HCHO, in regulating the atmospheric oxidation capacity and particulate sulfur chemistry in the marine atmosphere, urging further laboratory studies on chemical kinetics and field measurements of particle-phase carbonyls.

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Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase

Mekic,

Schaefer,

Hoffmann

et al. 2023

J. Phys. Chem. A

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T-dependent aqueous-phase rate constants were determined for the oxidation of the hydroxy aldehydes, glyceraldehyde, glycolaldehyde, and lactaldehyde, by the hydroxyl radicals (•OH), the sulfate radicals (SO4 •–), and the nitrate radicals (NO3 •). The obtained Arrhenius expressions for the oxidation by the •OH radical are: k (T,GLYCERALDEHYDE+OH•) = (3.3 ± 0.1) × 1010 × exp((−960 ± 80 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+OH•) = (4.3 ± 0.1) × 1011 × exp((−1740 ± 50 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+OH•) = (1.6 ± 0.1) × 1011 × exp((−1410 ± 180 K)/T)/L mol–1 s–1; for the SO4 •– radical: k (T,GLYCERALDEHYDE+SO4 •–) = (4.3 ± 0.1) × 109 × exp((−1400 ± 50 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+SO4 •–) = (10.3 ± 0.3) × 109 × exp((−1730 ± 190 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+SO4 •–) = (2.2 ± 0.1) × 109 × exp((−1030 ± 230 K)/T)/L mol–1 s–1; and for the NO3 • radical: k (T,GLYCERALDEHYDE+NO3 •) = (3.4 ± 0.2) × 1011 × exp((−3470 ± 460 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+NO3 •) = (7.8 ± 0.2) × 1011 × exp((−3820 ± 240 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+NO3 •) = (4.3 ± 0.2) × 1010 × exp((−2750 ± 340 K)/T)/L mol–1 s–1, respectively. Targeted simulations of multiphase chemistry reveal that the oxidation by OH radicals in cloud droplets is important under remote and wildfire influenced continental conditions due to enhanced partitioning. There, the modeled average aqueous •OH concentration is 2.6 × 10–14 and 1.8 × 10–14 mol L–1, whereas it is 7.9 × 10–14 and 3.5 × 10–14 mol L–1 under wet particle conditions. During cloud periods, the aqueous-phase reactions by •OH contribute to the oxidation of glycolaldehyde, lactaldehyde, and glyceraldehyde by about 35 and 29%, 3 and 3%, and 47 and 37%, respectively.

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Oxidation of low-molecular-weight organic compounds in cloud droplets: development of the Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC) in CAABA/MECCA (version 4.5.0)

Cited by 16 publications

References 60 publications

Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Carbonyl Compounds Regulate Atmospheric Oxidation Capacity and Particulate Sulfur Chemistry in the Coastal Atmosphere

Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase

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Oxidation of low-molecular-weight organic compounds in cloud droplets: development of the Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC) in CAABA/MECCA (version 4.5.0)

Cited by 16 publications

References 60 publications

Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

Carbonyl Compounds Regulate Atmospheric Oxidation Capacity and Particulate Sulfur Chemistry in the Coastal Atmosphere

Temperature-Dependent Oxidation of Hydroxylated Aldehydes by •OH, SO4•–, and NO3• Radicals in the Atmospheric Aqueous Phase

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Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase