Cloud model experiments of the effect of iron and copper on tropospheric ozone under marine and continental conditions

Matthijsen, J.; Builtjes, P. J. H.; Sedlak, David L.

doi:10.1007/bf01044153

Cited by 42 publications

(28 citation statements)

References 48 publications

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“…Both of these findings agree with of a host of previous box-modelling studies conducted to investigate the effect of clouds on HO x and O 3 formation (e.g. Lelieveld and Crutzen, 1991;Matthijsen et al, 1995;Walcek et al, 1997) and have been discussed at length in these articles. Therefore, since our work confirms previous studies, no further discussion concerning the fate of these radicals in the condensed phase is included here.…”

Section: Influence Of Cloudsupporting

confidence: 89%

The influence of cloud chemistry on HOx and NOx in the Marine Boundary Layer: a 1-D modelling study

Williams¹,

Dentener

Berg³

2001

Preprint

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Abstract. A 1-D marine stratocumulus cloud model has been supplemented with a comprehensive and up-to-date aqueous phase chemical mechanism for the purpose of assessing the impact that the presence of clouds and aerosols has on gas phase HOx, NOx and O3 budgets in the marine boundary layer. The simulations presented here indicate that cloud may act as a heterogeneous source of HONOg via the conversion of HNO4(g) at moderate pH (~4.5). The photolysis of nitrate (NO3-) has also been found to contribute to this simulated increase in HONOg by ~5% and also acts as a minor source of NO2(g). The effect of introducing deliquescent aerosol on the simulated increase of HONOg is negligible. The most important consequences of this elevation in HONOg are that, in the presence of cloud, gas phase concentrations of NOx species increase by a factor of 2, which minimises the simulated decrease in O3(g), and results in a regeneration of OHg. This partly compensates for the removal of OHg by direct phase transfer into the cloud and has important implications regarding the oxidising capacity of the marine boundary layer. The findings presented here also suggest that previous modelling studies, which neglect the heterogeneous HNO4(g) reaction cycle, may have over-estimated the role of clouds as a sink for OHg and O3(g)in unpolluted oceanic regions, by ~10% and ~2%, respectively.

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Section: Influence Of Cloudsupporting

confidence: 89%

The influence of cloud chemistry on HOx and NOx in the Marine Boundary Layer: a 1-D modelling study

Williams¹,

Dentener

Berg³

2001

Preprint

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“…3 Results and discussion R all ; without MSA + OH (aq) reaction R moreMSA+OH(aq) R all ; k MSA+OH(aq) × 4.7 (Milne et al, 1989) R lowOH(aq) R all ; OH (aq) concentrations in cloud droplets and aerosols reduced by a factor of 100 R add R all ; a unity yield of DMSO for the addition channel of DMS + OH reaction * R 10Cl R all ; Cl mixing ratios increased by a factor of 10 R all_onlyDMS R all ; DMS emission from the ocean as the only sulfur source R std_onlyDMS R std ;DMS emission from the ocean as the only sulfur source * The product yield for the addition channel of the DMS + OH reaction is highly uncertain. Product yields of 0.6 for SO 2 and 0.4 for DMSO have been commonly used in global models (Pham et al, 1995;Cosme et al, 2002;Spracklen et al, 2005;Breider et al, 2010) based on experiments described in Turnipseed et al (1996) and Hynes et al (1993), and are used in this study (e.g., in R all ).…”

Section: Geos-chem Modelmentioning

confidence: 99%

“…Knowledge about aqueous-phase concentrations of OH in cloud droplets and aerosols is still very limited. Modeled OH (aq) concentrations are on the order of 10 −14 -10 −12 M (Jacob, 1986;Matthijsen et al, 1995;Jacob et al, 1989;Herrmann et al, 2000). However, recent observations of OH (aq) , which are derived from the concentrations of dissolved organic compounds, are about 2 orders of magnitude lower (10 −16 -10 −14 M) (Arakaki et al, 2013;Kaur and Anastasio, 2017).…”

Section: Introductionmentioning

confidence: 97%

DMS oxidation and sulfur aerosol formation in the marine troposphere: a focus on reactive halogen and multiphase chemistry

et al. 2018

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Abstract. The oxidation of dimethyl sulfide (DMS) in the troposphere and subsequent chemical conversion into sulfur dioxide (SO2) and methane sulfonic acid (MSA) are key processes for the formation and growth of sulfur-containing aerosol and cloud condensation nuclei (CCN), but are highly simplified in large-scale models of the atmosphere. In this study, we implement a series of gas-phase and multiphase sulfur oxidation mechanisms into the Goddard Earth Observing System-Chemistry (GEOS-Chem) global chemical transport model – including two important intermediates, dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA) – to investigate the sulfur cycle in the global marine troposphere. We found that DMS is mainly oxidized in the gas phase by OH (66 %), NO3 (16 %) and BrO (12 %) globally. DMS + BrO is important for the model's ability to reproduce the observed seasonality of surface DMS mixing ratio in the Southern Hemisphere. MSA is mainly produced from multiphase oxidation of MSIA by OH(aq) (66 %) and O3(aq) (30 %) in cloud droplets and aerosols. Aqueous-phase reaction with OH accounts for only 12 % of MSA removal globally, and a higher MSA removal rate is needed to reproduce observations of the MSA ∕ nssSO42- ratio. The modeled conversion yield of DMS into SO2 and MSA is 75 % and 15 %, respectively, compared to 91 % and 9 % in the standard model run that includes only gas-phase oxidation of DMS by OH and NO3. The remaining 10 % of DMS is lost via deposition of intermediates DMSO and MSIA. The largest uncertainties for modeling sulfur chemistry in the marine boundary layer (MBL) are unknown concentrations of reactive halogens (BrO and Cl) and OH(aq) concentrations in cloud droplets and aerosols. To reduce uncertainties in MBL sulfur chemistry, we should prioritize observations of reactive halogens and OH(aq).

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“…20,34 Modeling studies have also looked at transition-metal redox chemistry in cloudwater. 19,32,35,36 Jacob et al concluded that the major source of S(VI) is the reaction S(IV) + Fe(III), provided a nonradical mechanism exists in which Fe(III) is not reduced. 19 Zuo et al have also looked at the photochemical decomposition of oxalic, glyoxalic, and pyruvic acid catalyzed by iron in atmospheric waters.…”

Section: Introductionmentioning

confidence: 98%

Measurements of Trace Metal (Fe, Cu, Mn, Cr) Oxidation States in Fog and Stratus Clouds

Siefert

Johansen

Hoffmann

et al. 1998

Journal of the Air & Waste Management Association

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The oxidation state of four transition metals (Fe, Mn, Cu, and Cr) in cloudwater has been investigated during several cloud events at Whiteface Mountain (NY), one cloud event at San Pedro Hill (CA), and one fog event at Bakers-field (CA). Samples were collected and immediately analyzed for the oxidation states of four transition metals: Fe(II) [44 measurements], Cu(I) [30 measurements], Mn(IV) [27 measurements], and Cr(III) [3 measurements]. Extreme care was taken to minimize contamination and interferences when measuring these oxidation states. Par-ticulate and dissolved concentrations of these metals were also determined. Other measurements performed-relevant to the redox chemistry of these metals-included pH, total elemental concentrations (Fe, Cu, Mn, Cr, Al, K, Ca, Na, and Mg), organic anions (formate, acetate, glyco-late, oxalate), inorganic anions (chloride, sulfate, nitrate, sulfite), cations (sodium, calcium, magnesium, potassium), peroxides, and formaldehyde. These measurements were then used in thermodynamic-speciation models to understand the speciation of ambient fog and cloudwater. From this analysis, two different cases were found for Fe(III)soluble speciation. Fe(III) was found to exist either as Fe(OH) or Fe(Oxalate). However, an unidentified strong chelating ligand with Fe(III) was also suggested by the data. Cu(I) and Cu(II) were calculated to be predominantly Cu and Cu (with less than 10% as Cu(II)-oxalate complexes). A chemical kinetic model was also used to investigate the transition-metal chemistry. The model results indicate that Fe(II) should be the predominant chemical form of Fe during daylight conditions. This prediction is in agreement with the field measurements in which the highest ratios of Fe(II)/Fe total were found in samples collected during the day. The model results also indicated that Fe(III) should be the predominant form of Fe during nighttime conditions, which is also in agreement with the field measurements. In the model, Cu(II) and Mn(II) were the predominant oxidation states during daylight and nighttime conditions with Cu(I) and Mn(III) increasing during daylight conditions. Mn(III) concentrations were never high enough to influence the redox chemistry of Cr. Overall, Cr(VI) in cloudwater is predicted to be reduced to Cr(III) if free S(IV) is present.

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Cloud model experiments of the effect of iron and copper on tropospheric ozone under marine and continental conditions

Cited by 42 publications

References 48 publications

The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the Marine Boundary Layer: a 1-D modelling study

The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the Marine Boundary Layer: a 1-D modelling study

DMS oxidation and sulfur aerosol formation in the marine troposphere: a focus on reactive halogen and multiphase chemistry

Measurements of Trace Metal (Fe, Cu, Mn, Cr) Oxidation States in Fog and Stratus Clouds

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Cloud model experiments of the effect of iron and copper on tropospheric ozone under marine and continental conditions

Cited by 42 publications

References 48 publications

The influence of cloud chemistry on HO&lt;sub&gt;x&lt;/sub&gt; and NO&lt;sub&gt;x&lt;/sub&gt; in the Marine Boundary Layer: a 1-D modelling study

The influence of cloud chemistry on HO&lt;sub&gt;x&lt;/sub&gt; and NO&lt;sub&gt;x&lt;/sub&gt; in the Marine Boundary Layer: a 1-D modelling study

DMS oxidation and sulfur aerosol formation in the marine troposphere: a focus on reactive halogen and multiphase chemistry

Measurements of Trace Metal (Fe, Cu, Mn, Cr) Oxidation States in Fog and Stratus Clouds

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The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the Marine Boundary Layer: a 1-D modelling study

The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the Marine Boundary Layer: a 1-D modelling study