Atmospheric Chemistry of Iodine
TL;DR: Atmospheric Chemistry of Iodine Alfonso Saiz-Lopez,* John M. C. Plane,* Alex R. Baker, Lucy J. Carpenter, Roland von Glasow, Juan C. G omez Martín, Gordon McFiggans, and Russell W. Smith.
Abstract: Atmospheric Chemistry of Iodine Alfonso Saiz-Lopez,* John M. C. Plane,* Alex R. Baker, Lucy J. Carpenter, Roland von Glasow, Juan C. G omez Martín, Gordon McFiggans, and Russell W. Saunders Laboratory for Atmospheric and Climate Science (CIAC), CSIC, Toledo, Spain School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom School of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom
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University of Leicester1, University of Cambridge2, Cooperative Institute for Research in Environmental Sciences3, Newbury College4, Earth System Research Laboratory5, University of Paris6, University of Edinburgh7, Paul Sabatier University8, Potsdam Institute for Climate Impact Research9, Lancaster University10, King's College London11
TL;DR: In this paper, a review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models and takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.
Abstract: Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a by-product of the very oxidation chemistry it largely initiates. Much effort is focussed on the reduction of surface levels of ozone owing to its health impacts but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve due to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate-change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.
877 citations
TL;DR: Reactive halogen species are potent oxidizers for organic and inorganic compounds throughout the troposphere and are powerful climate forcing agents through direct and indirect radiative effects.
Abstract: In the past 40 years, atmospheric chemists have come to realize that halogens exert a powerful influence on the chemical composition of the troposphere and through that influence affect the fate of pollutants and may affect climate. Of particular note for climate is that halogen cycles affect methane, ozone, and particles, all of which are powerful climate forcing agents through direct and indirect radiative effects. This influencecomes from the high reactivity of atomic halogen radicals (e.g.,Cl, Br, I) and halogen oxides (e.g., ClO, BrO, IO, and higher oxides), known as reactive halogen species in this review. These reactive halogens are potent oxidizers for organic and inorganic compounds throughout the troposphere.
329 citations
TL;DR: This critical review summarises the current understanding and uncertainties of the main halogen photochemistry processes, including the current knowledge of the atmospheric impact of halogen chemistry as well as open questions and future research needs.
Abstract: Halogen chemistry is well known for ozone destruction in the stratosphere, however reactive halogens also play an important role in the chemistry of the troposphere. In the last two decades, an increasing number of reactive halogen species have been detected in a wide range of environmental conditions from the polar to the tropical troposphere. Growing observational evidence suggests a regional to global relevance of reactive halogens for the oxidising capacity of the troposphere. This critical review summarises our current understanding and uncertainties of the main halogen photochemistry processes, including the current knowledge of the atmospheric impact of halogen chemistry as well as open questions and future research needs.
290 citations
Cites background from "Atmospheric Chemistry of Iodine"
...Saiz-Lopez et al. (2012)11 (SL12) presented a comprehensive review of the atmospheric chemistry of iodine....
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TL;DR: In this article, a review of the research progress of porous organic polymers (POPs) and metal-organic frameworks (MOFs), new classes of porous materials, act as outstanding candidate adsorbent materials in this field.
Abstract: The enrichment of radioactive iodine in the waste of nuclear industries threatens human health, and thus the efficient capture of iodine has attracted a great deal of attention in recent years. Porous organic polymers (POPs) and metal–organic frameworks (MOFs), new classes of porous materials, act as outstanding candidate adsorbent materials in this field due to their high surface areas, permanent tunable porosities, controllable structures, high thermal/chemical stabilities, versatility in molecular design and potential for post-synthetic modification. Herein, this review focuses on the research progress of these two types of porous materials for highly efficient iodine capture. We analyze and discuss some valid strategies for enhancing their iodine uptake, including increasing their surface area and pore volume, using organic building units with unique configurations and functions, introducing chemical functional groups to provide high-enthalpy binding sites, and further processing of POP and MOF materials. Indeed, there are many special structural and functional features found in porous POP and MOF materials, which make them unique and merit further exploration. Thus, we expect to see their usage grow as this field progresses.
287 citations
TL;DR: A novel class of solid materials for adsorption and separation, nonporous adaptive crystals (NACs), which function at the supramolecular level are described, which will not only exert a significant influence on scientific research but also show practical applications in chemical industry.
Abstract: ConspectusPorous materials with high surface areas have drawn more and more attention in recent years because of their wide applications in physical adsorption and energy-efficient adsorptive separation processes. Most of the reported porous materials are macromolecular porous materials, such as zeolites, metal–organic frameworks (MOFs), or porous coordination polymers (PCPs), and porous organic polymers (POPs) or covalent organic frameworks (COFs), in which the building blocks are linked together by covalent or coordinative bonds. These materials are barely soluble and thus are not solution-processable. Furthermore, the relatively low chemical, moisture, and thermal stability of most MOFs and COFs cannot be neglected. On the other hand, molecular porous materials such as porous organic cages (POCs), which have been developed very recently, also show promising applications in adsorption and separation processes. They can be soluble in organic solvents, making them solution-processable materials. However, ...
286 citations
References
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TL;DR: A critical evaluation of the kinetics and photochemistry of gas phase chemical reactions of neutral species involved in middle atmosphere chemistry (10-55 km altitude) was carried out by the authors under the auspices of the CODATA Task Group on Chemical Kinetics.
Abstract: This paper contains a critical evaluation of the kinetics and photochemistry of gas phase chemical reactions of neutral species involved in middle atmosphere chemistry (10–55 km altitude). The work has been carried out by the authors under the auspices of the CODATA Task Group on Chemical Kinetics. Data sheets have been prepared for 148 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each reaction a preferred value of the rate coefficient at 298 K is given together with a temperature dependency where possible. The selection of the preferred value is discussed, and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an Appendix listing the available data on enthalpies of formation of the reactant and product species.
1,661 citations
University of California, Riverside1, University of Leeds2, University of Cambridge3, Max Planck Society4, National Institute of Standards and Technology5, Commonwealth Scientific and Industrial Research Organisation6, Imperial College London7, École Polytechnique Fédérale de Lausanne8, University of Göttingen9
TL;DR: In this article, the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry presented the first in the series, presenting kinetic and photochemical data evaluated by the committee.
Abstract: . This article, the first in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Ox, HOx, NOx and SOx species, which were last published in 1997, and were updated on the IUPAC website in late 2001. The article consists of a summary sheet, containing the recommended kinetic parameters for the evaluated reactions, and five appendices containing the data sheets, which provide information upon which the recommendations are made.
1,612 citations
TL;DR: The first estimation of the power dependence of gas transfer on molecular diffusivity in the marine environment is reported in this paper, which allows the impact of bubbles on estimates of the transfer velocity derived from changes in the helium/sulphur hexafluoride ratio to be assessed.
Abstract: Measurements of air-sea gas exchange rates are reported from two deliberate tracer experiments in the southern North Sea during February 1992 and 1993. A conservative tracer, spores of the bacterium Bacillus globigii var. Niger, was used for the first time in an in situ air-sea gas exchange experiment. This nonvolatile tracer is used to correct for dispersive dilution of the volatile tracers and allows three estimations of the transfer velocity for the same time period. The first estimation of the power dependence of gas transfer on molecular diffusivity in the marine environment is reported. This allows the impact of bubbles on estimates of the transfer velocity derived from changes in the helium/sulphur hexafluoride ratio to be assessed. Data from earlier dual tracer experiments are reinterpreted, and findings suggest that results from all dual tracer experiments are mutually consistent. The complete data set is used to test published parameterizations of gas transfer with wind speed. A gas ex- change relationship that shows a dependence on wind speed intermediate between those ofLiss and Merlivat [1986] and Wanninkhof [1992] is found to be optimal. The dual tracer data are shown to be reasonably consistent with global estimates of gas exchange based on the uptake of natural and bomb-derived radiocarbon. The degree of scatter in the data when plotted against wind speed suggests that parameters not scaling with wind speed are also influencing gas exchange rates.
1,283 citations
TL;DR: In this paper, the authors identify specific compounds that are likely to contribute to the water-soluble fraction by juxtaposing observations regarding the extraction characteristics and the molecular composition of atmospheric particulate organics with compound-specific solubility and condensibility for a wide variety of organics.
Abstract: Although organic compounds typically constitute a substantial fraction of the fine particulate matter (PM) in the atmosphere, their molecular composition remains poorly characterized. This is largely because atmospheric particles contain a myriad of diverse organic compounds, not all of which extract in a single solvent or elute through a gas chromatograph; therefore, a substantial portion typically remains unanalyzed. Most often the chemical analysis is performed on a fraction that extracts in organic solvents such as benzene, ether or hexane; consequently, information on the molecular composition of the water-soluble fraction is particularly sparse and incomplete. This paper investigates theoretically the characteristics of the water-soluble fraction by splicing together various strands of information from the literature. We identify specific compounds that are likely to contribute to the water-soluble fraction by juxtaposing observations regarding the extraction characteristics and the molecular composition of atmospheric particulate organics with compound-specific solubility and condensibility for a wide variety of organics. The results show that water-soluble organics, which constitute a substantial fraction of the total organic mass, include C2 to C7 multifunctional compounds (e.g., diacids, polyols, amino acids). The importance of diacids is already recognized; our results provide an impetus for new experiments to establish the atmospheric concentrations and sources of polyols, amino acids and other oxygenated multifunctional compounds.
1,115 citations
TL;DR: It is found that during bloom periods, the organic fraction dominates and contributes 63% to the submicrometre aerosol mass (about 45% is water-insoluble and about 18% water-soluble) and is therefore an important component of the aerosol–cloud–climate feedback system involving marine biota.
Abstract: Marine aerosol contributes significantly to the global aerosol load and consequently has an important impact on both the Earth's albedo and climate. So far, much of the focus on marine aerosol has centred on the production of aerosol from sea-salt1 and non-sea-salt sulphates2,3. Recent field experiments, however, have shown that known aerosol production processes for inorganic species cannot account for the entire aerosol mass that occurs in submicrometre sizes4,5,6. Several experimental studies have pointed to the presence of significant concentrations of organic matter in marine aerosol7,8,9,10,11. There is some information available about the composition of organic matter12,13,14, but the contribution of organic matter to marine aerosol, as a function of aerosol size, as well as its characterization as hydrophilic or hydrophobic, has been lacking. Here we measure the physical and chemical characteristics of submicrometre marine aerosol over the North Atlantic Ocean during plankton blooms progressing from spring through to autumn. We find that during bloom periods, the organic fraction dominates and contributes 63% to the submicrometre aerosol mass (about 45% is water-insoluble and about 18% water-soluble). In winter, when biological activity is at its lowest, the organic fraction decreases to 15%. Our model simulations indicate that organic matter can enhance the cloud droplet concentration by 15% to more than 100% and is therefore an important component of the aerosol–cloud–climate feedback system involving marine biota.
890 citations