A reanalysis of carbonyl sulfide as a source of stratospheric background sulfur aerosol

Chin, Mian; Davis, D. D.

doi:10.1029/95jd00275

Cited by 218 publications

(213 citation statements)

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“…It is very interesting that the maximal yields of CO 2 and H 2 S lagged behind the maximal consumption of COS. This phenomenon is related to the adsorption of CO 2 and H 2 S on the basic site of MgO. In Figure 1, the maximal yield of H 2 S was also later than that of CO 2 , which could be explained by the reasons that the acidity of H 2 S is stronger than that of CO 2 , and thus H 2 S is more readily to be adsorbed on the basic site of MgO.…”

Section: Reaction Pathway and Kinetics For The Heterogeneousmentioning

confidence: 87%

“…The vacuum chamber between the QMS and the Knudsen cell reactor was pumped by a 60 L‚s -1 turbomolecular pump for differential pumping of the mass spectrometer and an ion gauge (both from BOC Edward). The Knudsen cell reactor consisted of a stainless steel chamber with a gas inlet controlled by a leak valve, an escape aperture whose area can be adjusted with an adjustable iris in the range of 0-300 mm 2 , and a sample holder attached to the top ceiling of a circulating fluid bath. The effective area of escape aperture was measured in each independent experiment according to the attenuation of the N 2 signal from one steady state to another.…”

Section: Experimental Methods Kcms Experimentsmentioning

confidence: 99%

“…As shown in Figure 1D-F, as the sample cover opened, desorption of CO 2 and H 2 S was clearly observed. When the sample cover was closed, the QMS signal for CO 2 and H 2 S decreased to their baselines. In Figure 1D, no desorption of COS was detected.…”

Section: Reaction Pathway and Kinetics For The Heterogeneousmentioning

confidence: 99%

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Temperature Dependence of the Heterogeneous Reaction of Carbonyl Sulfide on Magnesium Oxide

2008

J. Phys. Chem. A

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The experimental determination of rate constants for atmospheric reactions and how these rate constants vary with temperature remain a crucially important part of atmosphere science. In this study, the temperature dependence of the heterogeneous reaction of carbonyl sulfide (COS) on magnesium oxide (MgO) has been investigated using a Knudsen cell reactor and a temperature-programmed reaction apparatus. We found that the adsorption and the heterogeneous reaction are sensitive to temperature. The initial uptake coefficients (γ t (Ini)) of COS on MgO decrease from 1.07 ( 0.71 × 10 -6 to 4.84 ( 0.60 × 10 -7 with the increasing of temperature from 228 to 300 K, and the steady state uptake coefficients (γ t (SS)) increase from 5.31 ( 0.06 × 10 -8 to 1.68 ( 0.41 × 10 -7 with the increasing of temperature from 240 to 300 K. The desorption rate constants (k des ) were also found to increase slightly with the enhancement of temperature. The empirical formula between the uptake coefficients, desorption rate constants and temperature described in the form of Arrhenius expression were obtained. The activation energies for the heterogeneous reaction and desorption of COS on MgO were measured to be 11.02 ( 0.34 kJ‚mol -1 and 6.30 ( 0.81 kJ‚mol -1 , respectively. The results demonstrate that the initial uptake of COS on MgO is mainly contributed by an adsorption process and the steady state uptake is due to a catalytic reaction. The environmental implication was also discussed.

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Section: Reaction Pathway and Kinetics For The Heterogeneousmentioning

confidence: 87%

Section: Experimental Methods Kcms Experimentsmentioning

confidence: 99%

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Temperature Dependence of the Heterogeneous Reaction of Carbonyl Sulfide on Magnesium Oxide

2008

J. Phys. Chem. A

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“…This aerosol layer, referred to as the Junge layer, mainly consists of sulphate aerosol that is chiefly formed by sulphur dioxide (SO 2 ) produced from photo-dissociation of carbonyl sulphide (OCS) transported from the troposphere (Crutzen, 1976). However studies indicate that OCS is not enough to explain the observed aerosol load (Chin and Davis, 1995), and direct transport of SO 2 or sulphate aerosol have been suggested as important contributions to stratospheric aerosol (Pitari et al, 2002;Myhre et al, 2004). Volcanic injections however makes it difficult to determine the background state of the stratospheric aerosol layer (Solomon et al, 2011), and thereby the importance of different sources for its production.…”

mentioning

confidence: 99%

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

et al. 2013

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Large volcanic eruptions impact significantly on climate and lead to ozone depletion due to injection of particles and gases into the stratosphere where their residence times are long. In this the composition of volcanic aerosol is an important but inadequately studied factor. Samples of volcanically influenced aerosol were collected following the Kasatochi (Alaska), Sarychev (Russia) and also during the Eyjafjallajökull (Iceland) eruptions in the period 2008–2010. Sampling was conducted by the CARIBIC platform during regular flights at an altitude of 10–12 km as well as during dedicated flights through the volcanic clouds from the eruption of Eyjafjallajökull in spring 2010. Elemental concentrations of the collected aerosol were obtained by accelerator-based analysis. Aerosol from the Eyjafjallajökull volcanic clouds was identified by high concentrations of sulphur and elements pointing to crustal origin, and confirmed by trajectory analysis. Signatures of volcanic influence were also used to detect volcanic aerosol in stratospheric samples collected following the Sarychev and Kasatochi eruptions. In total it was possible to identify 17 relevant samples collected between 1 and more than 100 days following the eruptions studied. The volcanically influenced aerosol mainly consisted of ash, sulphate and included a carbonaceous component. Samples collected in the volcanic cloud from Eyjafjallajökull were dominated by the ash and sulphate component (&sim;45% each) while samples collected in the tropopause region and LMS mainly consisted of sulphate (50–77%) and carbon (21–43%). These fractions were increasing/decreasing with the age of the aerosol. Because of the long observation period, it was possible to analyze the evolution of the relationship between the ash and sulphate components of the volcanic aerosol. From this analysis the residence time (1/e) of sulphur dioxide in the studied volcanic cloud was estimated to be 45 ± 22 days

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“…1 OCS is relatively unreactive in the troposphere, where it is present at near constant mixing ratios of ∼500 ppt, but concentrations drop off sharply in the stratosphere, as shorter wavelength photolysis becomes increasingly important. 2 As a source of atomic sulfur, photolysis of OCS makes a significant nonvolcanic contribution to the stratospheric sulfate aerosol layer. 3,4 The first absorption band of OCS is responsible for its photochemistry in the stratospheric UV window and has been extensively studied.…”

Section: ■ Introductionmentioning

confidence: 99%

Decomposing the First Absorption Band of OCS Using Photofragment Excitation Spectroscopy

Toulson

Murray

2016

J. Phys. Chem. A

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Photofragment excitation spectra of carbonyl sulfide (OCS) have been recorded from 212−260 nm by state-selectively probing either electronically excited S( 1 D) or ground state S( 3 P) photolysis products via 2 + 1 resonance-enhanced multiphoton ionization. Probing the major S( 1 D) product results in a broad, unstructured action spectrum that reproduces the overall shape of the first absorption band. In contrast, spectra obtained probing S( 3 P) products display prominent resonances superimposed on a broad continuum; the resonances correspond to the diffuse vibrational structure observed in the conventional absorption spectrum. The vibrational structure is assigned to four progressions, each dominated by the C−S stretch, ν 1 , following direct excitation to quasi-bound singlet and triplet states. The S( 3 P J ) products are formed with a near-statistical population distribution over the J = 2, 1, and 0 spin−orbit levels across the wavelength range investigated. Although a minor contributor to the S atom yield near the peak of the absorption cross section, the relative yield of S( 3 P) increases significantly at longer wavelengths. The experimental measurements validate recent theoretical work characterizing the electronic states responsible for the first absorption band by Schmidt and co-workers.

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A reanalysis of carbonyl sulfide as a source of stratospheric background sulfur aerosol

Cited by 218 publications

References 51 publications

Temperature Dependence of the Heterogeneous Reaction of Carbonyl Sulfide on Magnesium Oxide

Temperature Dependence of the Heterogeneous Reaction of Carbonyl Sulfide on Magnesium Oxide

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

Decomposing the First Absorption Band of OCS Using Photofragment Excitation Spectroscopy

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