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Abstract
Recycling of reactive iodine from heterogeneous processes on sea-salt aerosol was hypothesized over two decades ago to play an important role in the atmospheric cleansing capacity. However, the understanding of this mechanism has been limited to laboratory studies and has not been confirmed in the atmosphere until now. We present atmospheric measurement of gas-phase iodine interhalogen species and show that their production via heterogeneous processing on marine aerosols is remarkably fast. These observations reveal that the atmospheric recycling of atomic iodine through photolysis of iodine interhalogen species is more efficient than previously thought, which is ultimately expected to lead to higher ozone loss and faster new particle formation in the marine environment. Reactive iodine plays a key role in determining the oxidation capacity, or cleansing capacity, of the atmosphere in addition to being implicated in the formation of new particles in the marine boundary layer. The postulation that heterogeneous cycling of reactive iodine on aerosols may significantly influence the lifetime of ozone in the troposphere not only remains poorly understood but also heretofore has never been observed or quantified in the field. Here, we report direct ambient observations of hypoiodous acid (HOI) and heterogeneous recycling of interhalogen product species (i.e., iodine monochloride [ICl] and iodine monobromide [IBr]) in a midlatitude coastal environment. Significant levels of ICl and IBr with mean daily maxima of 4.3 and 3.0 parts per trillion by volume (1-min average), respectively, have been observed throughout the campaign. We show that the heterogeneous reaction of HOI on marine aerosol and subsequent production of iodine interhalogens are much faster than previously thought. These results indicate that the fast formation of iodine interhalogens, together with their rapid photolysis, results in more efficient recycling of atomic iodine than currently considered in models. Photolysis of the observed ICl and IBr leads to a 32% increase in the daytime average of atomic iodine production rate, thereby enhancing the average daytime iodine-catalyzed ozone loss rate by 10 to 20%. Our findings provide direct field evidence that the autocatalytic mechanism of iodine release from marine aerosol is important in the atmosphere and can have significant impacts on atmospheric oxidation capacity.
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Hoffmann EH, Tilgner A, Wolke R, Herrmann H. Enhanced Chlorine and Bromine Atom Activation by Hydrolysis of Halogen Nitrates from Marine Aerosols at Polluted Coastal Areas. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:771-778. [PMID: 30557005 DOI: 10.1021/acs.est.8b05165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Detailed multiphase chemistry box model studies are carried out, investigating halogen radical activation at polluted coastal areas. Simulations are performed for a nonpermanent cloud and a cloud-free scenario and reveal that ClNO2 photolysis and ICl photolysis are crucial for gas-phase Cl atom activation. In the cloud scenario, the integrated ClNO2 and ICl photolysis rates are 3.7 × 107 and 3.1 × 107 molecules cm-3 s-1. In the cloud-free scenario, the integrated ClNO2 and ICl photolysis rates are 8.1 × 107 and 3.6 × 107 molecules cm-3 s-1. The simulations show larger contributions of ClNO2 photolysis in the morning and higher ones of ICl photolysis during afternoon. Throughout the simulation, average contributions to Cl atom activation in the cloud and cloud-free scenarios by ClNO2 photolysis are 42% and 62% and by ICl photolysis 35% and 28%, respectively. ICl is formed through an aqueous-phase reaction of HOI with chloride. Two thirds of the formed ICl is released into the gas phase. The residual third reacts with bromide, creating IBr. Overall, the simulations emphasize the crucial role of INO3 hydrolysis for Cl and Br atom activation in polluted coastal areas. Therefore, it needs to be considered in chemical transport models to improve air quality predictions.
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Affiliation(s)
- Erik H Hoffmann
- Leibniz Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , D-04318 Leipzig , Germany
| | - Andreas Tilgner
- Leibniz Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , D-04318 Leipzig , Germany
| | - Ralf Wolke
- Leibniz Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , D-04318 Leipzig , Germany
| | - Hartmut Herrmann
- Leibniz Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , D-04318 Leipzig , Germany
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Sherwen T, Evans MJ, Sommariva R, Hollis LDJ, Ball SM, Monks PS, Reed C, Carpenter LJ, Lee JD, Forster G, Bandy B, Reeves CE, Bloss WJ. Effects of halogens on European air-quality. Faraday Discuss 2018; 200:75-100. [PMID: 28581558 DOI: 10.1039/c7fd00026j] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Halogens (Cl, Br) have a profound influence on stratospheric ozone (O3). They (Cl, Br and I) have recently also been shown to impact the troposphere, notably by reducing the mixing ratios of O3 and OH. Their potential for impacting regional air-quality is less well understood. We explore the impact of halogens on regional pollutants (focussing on O3) with the European grid of the GEOS-Chem model (0.25° × 0.3125°). It has recently been updated to include a representation of halogen chemistry. We focus on the summer of 2015 during the ICOZA campaign at the Weybourne Atmospheric Observatory on the North Sea coast of the UK. Comparisons between these observations together with those from the UK air-quality network show that the model has some skill in representing the mixing ratios/concentration of pollutants during this period. Although the model has some success in simulating the Weybourne ClNO2 observations, it significantly underestimates ClNO2 observations reported at inland locations. It also underestimates mixing ratios of IO, OIO, I2 and BrO, but this may reflect the coastal nature of these observations. Model simulations, with and without halogens, highlight the processes by which halogens can impact O3. Throughout the domain O3 mixing ratios are reduced by halogens. In northern Europe this is due to a change in the background O3 advected into the region, whereas in southern Europe this is due to local chemistry driven by Mediterranean emissions. The proportion of hourly O3 above 50 nmol mol-1 in Europe is reduced from 46% to 18% by halogens. ClNO2 from N2O5 uptake onto sea-salt leads to increases in O3 mixing ratio, but these are smaller than the decreases caused by the bromine and iodine. 12% of ethane and 16% of acetone within the boundary layer is oxidised by Cl. Aerosol response to halogens is complex with small (∼10%) reductions in PM2.5 in most locations. A lack of observational constraints coupled to large uncertainties in emissions and chemical processing of halogens make these conclusions tentative at best. However, the results here point to the potential for halogen chemistry to influence air quality policy in Europe and other parts of the world.
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Affiliation(s)
- T Sherwen
- Wolfson Atmospheric Chemistry Laboratory, University of York, York, UK.
| | - M J Evans
- Wolfson Atmospheric Chemistry Laboratory, University of York, York, UK. and National Centre for Atmospheric Science (NCAS), University of York, York, UK
| | - R Sommariva
- Department of Chemistry, University of Leicester, Leicester, UK
| | - L D J Hollis
- Department of Chemistry, University of Leicester, Leicester, UK
| | - S M Ball
- Department of Chemistry, University of Leicester, Leicester, UK
| | - P S Monks
- Department of Chemistry, University of Leicester, Leicester, UK
| | - C Reed
- Wolfson Atmospheric Chemistry Laboratory, University of York, York, UK.
| | - L J Carpenter
- Wolfson Atmospheric Chemistry Laboratory, University of York, York, UK.
| | - J D Lee
- Wolfson Atmospheric Chemistry Laboratory, University of York, York, UK. and National Centre for Atmospheric Science (NCAS), University of York, York, UK
| | - G Forster
- NCAS, School of Environmental Sciences, University of East Anglia, Norwich, UK and School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - B Bandy
- School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - C E Reeves
- School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - W J Bloss
- School of Geography, Earth and Environmental Science, University of Birmingham, Birmingham, UK
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Larin IK, Spasskii AI, Trofimova EM, Proncheva NG. Measurement of the Rate Constant of a Reaction of Chlorine Atoms with CH3Br in a Temperature Range of 298–358 K Using the Resonance Fluorescence of Chlorine Atoms. KINETICS AND CATALYSIS 2018. [DOI: 10.1134/s002315841801007x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Larin IK, Spasskii AI, Trofimova EM, Proncheva NG. Measuring the rate constant of the reaction between chlorine atoms and CHF2Br by Cl atom resonance fluorescence. KINETICS AND CATALYSIS 2016. [DOI: 10.1134/s0023158416030101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Bailleux S, Duflot D, Aiba S, Nakahama S, Ozeki H. Nitrosyl iodide, INO: A combined ab initio and high-resolution spectroscopic study. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.02.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Fritz BG, Phillips NRJ. Use of CAP88 PC to infer differences in the chemical form of 129I emitted from a fuel reprocessing facility. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 120:1-5. [PMID: 23395750 DOI: 10.1016/j.jenvrad.2013.01.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/11/2013] [Accepted: 01/18/2013] [Indexed: 06/01/2023]
Abstract
Emissions of (129)I from nuclear fuel separations conducted at the Hanford Site in Washington State have been occurring since the 1940's. Fuel separation on the Hanford Site stopped in 1988, but emissions of (129)I have continued as venting of the PUREX Plant occurred. In this study, atmospheric measurements of (129)I concentrations were coupled with an EPA approved plume dispersion model (CAP88-PC, Version 3.0) to evaluate the effectiveness of the dispersion model for estimating ambient concentrations at the Hanford Site. This evaluation led to the hypothesis that different chemical forms of iodine were being emitted over the years; this hypothesis was developed as an explanation for the model agreeing with measurements over some time periods, but not over all time periods. The model was then run with modified emissions to simulate the short atmospheric half-life of the suspected reactive chemical form of iodine being emitted. This modification resulted in good agreement between the modeled and measured concentrations over the entire 20 year study period (1986-2005), and provided evidence supporting the hypothesis of a reactive form of iodine being emitted.
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Affiliation(s)
- Brad G Fritz
- Pacific Northwest National Laboratory, P.O. Box 999, MS K6-75, Richland, WA 99352, USA.
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Mazaheri M, Bostrom TE, Johnson GR, Morawska L. Composition and morphology of particle emissions from in-use aircraft during takeoff and landing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:5235-5242. [PMID: 23618073 DOI: 10.1021/es3046058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In order to provide realistic data for air pollution inventories and source apportionment at airports, the morphology and composition of ultrafine particles (UFP) in aircraft engine exhaust were measured and characterized. For this purpose, two independent measurement techniques were employed to collect emissions during normal takeoff and landing operations at Brisbane Airport, Australia. PM1 emissions in the airfield were collected on filters and analyzed using the particle-induced X-ray emission (PIXE) technique. Morphological and compositional analyses of individual ultrafine particles in aircraft plumes were performed on silicon nitride membrane grids using transmission electron microscopy (TEM) combined with energy-dispersive X-ray microanalysis (EDX). TEM results showed that the deposited particles were in the range of 5-100 nm in diameter, had semisolid spherical shapes and were dominant in the nucleation mode (18-20 nm). The EDX analysis showed the main elements in the nucleation particles were C, O, S, and Cl. The PIXE analysis of the airfield samples was generally in agreement with the EDX in detecting S, Cl, K, Fe, and Si in the particles. The results of this study provide important scientific information on the toxicity of aircraft exhaust and their impact on local air quality.
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Affiliation(s)
- Mandana Mazaheri
- International Laboratory for Air Quality and Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4001, Australia
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Saavedra P, Battaglia A, Simmer C. Partitioning of cloud water and rainwater content by ground-based observations with the Advanced Microwave Radiometer for Rain Identification (ADMIRARI) in synergy with a micro rain radar. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016579] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Saiz-Lopez A, Plane JMC, Baker AR, Carpenter LJ, von Glasow R, Gómez Martín JC, McFiggans G, Saunders RW. Atmospheric Chemistry of Iodine. Chem Rev 2011; 112:1773-804. [DOI: 10.1021/cr200029u] [Citation(s) in RCA: 383] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Alfonso Saiz-Lopez
- Laboratory for Atmospheric and Climate Science (CIAC), CSIC, Toledo, Spain
| | - John M. C. Plane
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alex R. Baker
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Lucy J. Carpenter
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Roland von Glasow
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Gordon McFiggans
- School of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom
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Atmospheric reactivity of CH3I and CH2I2 with OH radicals: A comparative study of the H- versus I-abstraction. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.theochem.2010.09.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Qu Z, Yan N, Liu P, Jia J, Yang S. The role of iodine monochloride for the oxidation of elemental mercury. JOURNAL OF HAZARDOUS MATERIALS 2010; 183:132-137. [PMID: 20674159 DOI: 10.1016/j.jhazmat.2010.06.126] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 05/25/2010] [Accepted: 06/30/2010] [Indexed: 05/29/2023]
Abstract
The removal of Hg(0) by the homogenous gas-phase reaction and particle-induced reaction was investigated under various conditions. Iodine monochloride was found to be efficient for Hg(0) oxidation, with the apparent 2nd-order rate constant of about 10.5(±0.3)×10(-17) cm(3) molecules(-1) s(-1) and 5.7(±0.3)×10(-17) cm(3) molecules(-1) s(-1) at 273 K and 373 K, respectively. The pilot-scale tests showed that the removal of Hg(0) by ICl increased significantly in presence of flyash. It was predicted that over 90% of Hg(0) removal efficiency can be obtained with 0.2 ppmv ICl and 20 g/m(3) flyash in flue gas. Though the reaction between Hg(0) and ICl was by far faster than that of Hg(0)/Cl(2), the major product was found to be HgCl(2) rather than HgI(2), which implicated that iodine might partly act as the accelerant in Hg(0) oxidation by facilitating the formation of certain intermediates. The results indicated that using ICl to oxidize elemental mercury in coal-fired flue gas can save the consumption of iodine, and it appeared to be a promising oxidant to enhance the removal of Hg(0).
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Affiliation(s)
- Zan Qu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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Grant DJ, Garner EB, Matus MH, Nguyen MT, Peterson KA, Francisco JS, Dixon DA. Thermodynamic Properties of the XO2, X2O, XYO, X2O2, and XYO2 (X, Y = Cl, Br, and I) Isomers. J Phys Chem A 2010; 114:4254-65. [DOI: 10.1021/jp911320p] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Daniel J. Grant
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - Edward B. Garner
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - Myrna H. Matus
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - Minh Tho Nguyen
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - Kirk A. Peterson
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - Joseph S. Francisco
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
| | - David A. Dixon
- Chemistry Department, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruz, México, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, Department of Chemistry, H. C. Brown Laboratory, Purdue University, West Lafayette, Indiana 47907-1393, and Department of Chemistry, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
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Huang RJ, Hoffmann T. Development of a Coupled Diffusion Denuder System Combined with Gas Chromatography/Mass Spectrometry for the Separation and Quantification of Molecular Iodine and the Activated Iodine Compounds Iodine Monochloride and Hypoiodous Acid in the Marine Atmosphere. Anal Chem 2009; 81:1777-83. [DOI: 10.1021/ac801839v] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ru-Jin Huang
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Thorsten Hoffmann
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
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A denuder–impinger system with in situ derivatization followed by gas chromatography–mass spectrometry for the determination of gaseous iodine-containing halogen species. J Chromatogr A 2008; 1210:135-41. [PMID: 18849042 DOI: 10.1016/j.chroma.2008.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/30/2008] [Accepted: 08/01/2008] [Indexed: 11/21/2022]
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17
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Kaltsoyannis N, Plane JMC. Quantum chemical calculations on a selection of iodine-containing species (IO, OIO, INO3, (IO)2, I2O3, I2O4 and I2O5) of importance in the atmosphere. Phys Chem Chem Phys 2008; 10:1723-33. [DOI: 10.1039/b715687c] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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18
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19
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Braban CF, Adams JW, Rodriguez D, Cox RA, Crowley JN, Schuster G. Heterogeneous reactions of HOI, ICl and IBr on sea salt and sea salt proxies. Phys Chem Chem Phys 2007; 9:3136-48. [PMID: 17612737 DOI: 10.1039/b700829e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The heterogeneous chemistry of HOI, ICl and IBr on sea salt and sea salt proxies has been studied at 274 K using two experimental approaches: a wetted wall flow tube coupled to an electron impact mass spectrometer (WWFT-MS) and an aerosol flow tube (AFT) coupled to a differential mobility analyser (DMA) and a chemical ionisation mass spectrometer (CIMS). Uptake of all three title molecules into bulk aqueous halide salt films was rapid and controlled by gas phase diffusion. Uptake of HOI gave rise to gas-phase ICl and IBr, with the latter being the predominant product whenever Br(-) was present. Only partial release of IBr was observed due to high solubility of dihalogens in the film. ICl uptake gave the same yield of IBr as HOI uptake. Uptake of ICl on NaBr aerosol was accommodation limited with alpha = 0.018 +/- 0.004 and gas phase IBr product has a yield of 0.6 +/- 0.3. The results show that HOI can act as a catalyst for activation of bromine from sea-salt aerosols in the marine boundary layer, via the reactions: HOI(aq) + Cl + H--> ICl(aq) + H(2)O(l) and ICl(aq) + Br--> IBr(aq) + Cl.
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Affiliation(s)
- C F Braban
- Department of Chemistry, University of Cambridge, Lensfield Rd, Cambridge, UK
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20
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Zhang H, Zhang GL, Wang L, Liu B, Yu XY, Li ZS. Theoretical study on the Br + CH3SCH3 reaction. J Comput Chem 2007; 28:1153-9. [PMID: 17285559 DOI: 10.1002/jcc.20646] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The multiple-channel reactions Br + CH(3)SCH(3) --> products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6-31+G(d,p) level, and energetic information is further refined by the G3(MP2) (single-point) theory. The rate constants for every reaction channels, Br + CH(3)SCH(3) --> CH(3)SCH(2) + HBr (R1), Br + CH(3)SCH(3) --> CH(3)SBr + CH(3) (R2), and Br + CH(3)SCH(3) -->CH(3)S + CH(3)Br (R3), are calculated by canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200-3000 K. The total rate constants are in good agreement with the available experimental data, and the two-parameter expression k(T) = 2.68 x 10(-12) exp(-1235.24/T) cm(3)/(molecule s) over the temperature range 200-3000 K is given. Our calculations indicate that hydrogen abstraction channel is the major channel due to the smallest barrier height among three channels considered, and the other two channels to yield CH(3)SBr + CH(3) and CH(3)S + CH(3)Br are minor channels over the whole temperature range.
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Affiliation(s)
- Hui Zhang
- College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, People's Republic of China
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21
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Tucceri ME, Hölscher D, Rodriguez A, Dillon TJ, Crowley JN. Absorption cross section and photolysis of OIO. Phys Chem Chem Phys 2006; 8:834-46. [PMID: 16482325 DOI: 10.1039/b512702e] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Pulsed laser photolysis combined with transient absorption spectroscopy and resonance fluorescence was used to examine the photolysis of OIO at a number of wavelengths corresponding to absorption bands in its visible spectrum between approximately 530 and 570 nm. Photolysis at 532 nm was found to result in substantial depopulation of the absorbing ground state, enabling an estimate for the absorption cross section of OIO at 610.2 nm of (6 +/- 2) x 10(-18) cm2 molecule(-1) to be obtained. No evidence was found for I atom formation following photolysis of OIO at 532, 562.3, 567.9 and 573.8 nm, enabling an upper limit to the I atom quantum yield of < 0.05 (560-580 nm) and < 0.24 (532 nm) to be established.
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Affiliation(s)
- M E Tucceri
- Max-Planck-Institut für Chemie, Division of Atmospheric Chemistry, Germany
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Plane JMC, Joseph DM, Allan BJ, Ashworth SH, Francisco JS. An Experimental and Theoretical Study of the Reactions OIO + NO and OIO + OH. J Phys Chem A 2005; 110:93-100. [PMID: 16392844 DOI: 10.1021/jp055364y] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The kinetics of the reaction OIO+NO were studied by pulsed laser photolysis/time-resolved cavity ring-down spectroscopy, yielding k(235-320 K)=7.6(+4.0)(-3.1) x 10(-13) exp[(607+/-128)/T] cm3 molecule-1 s-1. Quantum calculations on the OIO+NO potential-energy surface show that the reactants form a weakly bound OIONO intermediate, which then dissociates to the products IO+NO2. Rice-Ramsberger-Kassel-Markus (RRKM) calculations on this surface are in good accord with the experimental result. The most stable potential product, IONO2, cannot form because of the significant rearrangement of OIONO that would be required. The reaction OIO+OH was then investigated by quantum calculations of the relevant stationary points on its potential-energy surface. The very stable HOIO2 molecule can form by direct recombination, but the bimolecular reaction channels to HO2+IO and HOI+O2 are closed because of significant energy barriers. RRKM calculations of the HOIO2 recombination rate coefficient yield krec,0=1.5x10(-27) (T/300 K)(-3.93) cm6 molecule-2 s-1, krec,infinity=5.5x10(-10) exp(46/T) cm3 molecule-1 s-1, and Fc=0.30. The rate coefficients of both reactions are fast enough around 290 K and 1 atm pressure for these reactions to play a potentially important role in the gas phase and aerosol chemistry in the marine boundary layer of the atmosphere.
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Affiliation(s)
- J M C Plane
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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García P, Pernice H, Willner H, Oberhammer H, Argüello GA. Properties of Chloroformyl Peroxynitrate, ClC(O)OONO2. Inorg Chem 2005; 44:4415-20. [PMID: 15934773 DOI: 10.1021/ic050229l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of ClC(O)OONO(2) is accomplished by photolysis of a mixture of Cl(2), NO(2), and CO in large excess of O(2) at about -70 degrees C. The product is isolated after repeated trap-to-trap condensation. The solid compound melts at -84 degrees C, and the extrapolated boiling point is 80 degrees C. ClC(O)OONO(2) is characterized by IR, Raman, (13)C NMR, and UV spectroscopy. According to the IR matrix spectra, the compound exists at room temperature only as a single conformer. The molecular structure of ClC(O)OONO(2) is determined by gas electron diffraction. The molecule possesses a gauche structure with a dihedral angle of phi(COON) = 86.7(19) degrees , and the C=O bond is oriented syn with respect to the O-O bond. The short O-O bond (1.418(6) A) and the long N-O bond (1.511(8) A) are consistent with the facile dissociation of ClC(O)OONO(2) into the radicals ClC(O)OO and NO(2). The experimental geometry of ClC(O)OONO(2) is reproduced reasonably well by B3LYP/6-311+G(2df) calculations, whereas the MP2 approximation predicts the N-O bond considerably too long and the dihedral angle too small.
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Affiliation(s)
- Plácido García
- FB C, Anorganische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, D-42097 Wuppertal, Germany
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Enami S, Nakano Y, Hashimoto S, Kawasaki M, Aloisio S, Francisco JS. Reactions of Cl Atoms with Dimethyl Sulfide: A Theoretical Calculation and an Experimental Study with Cavity Ring-Down Spectroscopy. J Phys Chem A 2004. [DOI: 10.1021/jp049772y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shinichi Enami
- Department of Molecular Engineering and Graduate School of Global Environmental Studies, Kyoto University, Kyoto 615-8510, Japan
| | - Yukio Nakano
- Department of Molecular Engineering and Graduate School of Global Environmental Studies, Kyoto University, Kyoto 615-8510, Japan
| | - Satoshi Hashimoto
- Department of Molecular Engineering and Graduate School of Global Environmental Studies, Kyoto University, Kyoto 615-8510, Japan
| | - Masahiro Kawasaki
- Department of Molecular Engineering and Graduate School of Global Environmental Studies, Kyoto University, Kyoto 615-8510, Japan
| | - Simone Aloisio
- California State University, Channel Islands, One University Drive, California, California 93010
| | - Joseph S. Francisco
- Department of Chemistry and Earth & Atmospheric Science, Purdue University, West Lafayette, Indiana 47907-1393
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Goodsite ME, Plane JMC, Skov H. A theoretical study of the oxidation of Hg0 to HgBr2 in the troposphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:1772-6. [PMID: 15074688 DOI: 10.1021/es034680s] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The oxidation of elemental mercury (Hg0) to the divalent gaseous mercury dibromide (HgBr2) has been proposed to account for the removal of Hg0 during depletion events in the springtime Arctic. The mechanism of this process is explored in this paper by theoretical calculations of the relevant rate coefficients. Rice-Ramsberger-Kassel-Marcus (RRKM) theory, together with ab initio quantum calculations where required, are used to estimate the following: recombination rate coefficients of Hg with Br, I, and O; the thermal dissociation rate coefficient of HgBr; and the recombination rate coefficients of HgBr with Br, I, OH, and O2. A mechanism based on the initial recombination of Hg with Br, followed by the addition of a second radical (Br, I, or OH) in competition with thermal dissociation of HgBr, is able to account for the observed rate of Hg0 removal, both in Arctic depletion events and at lower latitudes.
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Affiliation(s)
- M E Goodsite
- Department of Atmospheric Environment, National Environmental Research Institute, Roskilde, Denmark.
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Affiliation(s)
- Michel J Rossi
- Laboratoire de Pollution Atmosphérique et Sol (LPAS), Institut des Sciences et Techniques de l'Environnement (ISTE), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Affiliation(s)
- Lucy J Carpenter
- Department of Chemistry, University of York, York YO10 5DD, U.K.
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