Quantitative detection of iodine in the stratosphere

Koenig, Theodore K.; Baidar, Sunil; Campuzano‐Jost, Pedro; Cuevas, Carlos A.; Dix, B.; Fernández, Rafael P.; Guo, Hongyu; Hall, Samuel R.; Kinnison, Douglas E.; Nault, Benjamin A.; Ullmann, Kirk; Jimenez, José L.; Saiz‐Lopez, Alfonso; Volkamer, Rainer

doi:10.1073/pnas.1916828117

Cited by 94 publications

(149 citation statements)

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“…Another active iodine chemistry region is the tropical upper troposphere-lower stratosphere region (UTLS), where significant concentrations of iodine exist (Koenig et al, 2020) as a result of strong convection carrying iodine precursors emitted at the ocean surface (mainly CH 3 I). The effect of the new spectra on the J values in this region is similar to the effect at the surface, although the changes are less pronounced.…”

Section: Atmospheric Implicationsmentioning

confidence: 99%

“…Recent nitrate ion chemical ionization-atmospheric pressure interface-time-of-flight mass spectrometry (NO − 3 CI-API-ToF-MS) observations of IO − 3 -and IO 3 -containing ion clusters in coastal and polar environments, as well as complementary laboratory experiments in the absence of HO x , have been interpreted as direct measurements of gas-phase iodic acid (HOIO 2 , hereafter denoted as HIO 3 ) and HIO 3 clusters (Sipilä et al, 2016) by ionization of the ambient species by NO − 3 in the instrument inlet. Since all possible reaction paths for I, IO, and OIO with H 2 O are very endothermic (Canneaux et al, 2010;Hammaecher et al, 2011;Khanniche et al, 2017a) and IO x −H 2 O complexes are very weakly bound (Galvez et al, 2013), the formation of oxyacids may rather proceed via hydrolysis of higher iodine oxides (Kumar et al, 2018):…”

Section: Introductionmentioning

confidence: 99%

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Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

et al. 2020

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Abstract. Iodine oxides (IxOy) play an important role in the atmospheric chemistry of iodine. They are initiators of new particle formation events in the coastal and polar boundary layers and act as iodine reservoirs in tropospheric ozone-depleting chemical cycles. Despite the importance of the aforementioned processes, the photochemistry of these molecules has not been studied in detail previously. Here, we report the first determination of the absorption cross sections of IxOy, x=2, 3, 5, y=1–12 at λ=355 nm by combining pulsed laser photolysis of I2∕O3 gas mixtures in air with time-resolved photo-ionization time-of-flight mass spectrometry, using NO2 actinometry for signal calibration. The oxides selected for absorption cross-section determinations are those presenting the strongest signals in the mass spectra, where signals containing four iodine atoms are absent. The method is validated by measuring the absorption cross section of IO at 355 nm, σ355nm,IO= (1.2±0.1) ×10-18 cm2, which is found to be in good agreement with the most recent literature. The results obtained are σ355nm,I2O3<5×10-19 cm2 molec.−1, σ355nm,I2O4= (3.9±1.2)×10-18 cm2 molec.−1, σ355nm,I3O6= (6.1±1.6)×10-18 cm2 molec.−1, σ355nm,I3O7= (5.3±1.4)×10-18 cm2 molec.−1, and σ355nm,I5O12= (9.8±1.0)×10-18 cm2 molec.−1. Photodepletion at λ=532 nm was only observed for OIO, which enabled determination of upper limits for the absorption cross sections of IxOy at 532 nm using OIO as an actinometer. These measurements are supplemented with ab initio calculations of electronic spectra in order to estimate atmospheric photolysis rates J(IxOy). Our results confirm a high J(IxOy) scenario where IxOy is efficiently removed during daytime, implying enhanced iodine-driven ozone depletion and hindering iodine particle formation. Possible I2O3 and I2O4 photolysis products are discussed, including IO3, which may be a precursor to iodic acid (HIO3) in the presence of HO2.

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Section: Atmospheric Implicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

et al. 2020

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“…Currently, inorganic iodine emissions are considered to be the dominant sources contributing to the open ocean boundary layer iodine (Carpenter et al, 2013). A recent study by Koenig et al (2020) concluded that inorganic iodine sources play major role in comparison to the organic iodine sources in contributing even to the upper troposphere iodine budget. Laboratory investigations revealed that at the ocean surface, iodide (I -) dissolved in the seawater reacts with the deposited https://doi.org/10.5194/acp-2019-1052 Preprint.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Reactive Inorganic Iodine Fluxes in the Indian and Southern Ocean Marine Boundary Layer

Inamdar¹,

Tinel²,

Chance³

et al. 2020

Preprint

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Abstract. Iodine chemistry has noteworthysignificant impacts on the oxidising capacity of the marine boundary layer (MBL) through the depletion of ozone (O3) and changes to HOx (OH/HO2) and NOx (NO/NO2) ratios. Hitherto, studies have shown that the reaction of atmospheric O3 with surface seawater iodide (I−) contributes to the flux of iodine species into the MBL mainly as hypoiodous acid (HOI) and molecular iodine (I2). Here, we present the first concomitant observations of iodine oxide (IO), O3 in the gas phase, and sea surface iodide concentrations. The results from three field campaigns in the Indian Ocean and the Southern Ocean during 2014–2017 are used to compute reactive iodine fluxes to the MBL. Observations of atmospheric IO by MAX-DOAS show active iodine chemistry in this environment, with IO values up to 1 pptv (parts per trillion by volume) below latitudes of 40° S. In order to compute the sea-to-air iodine flux supporting this chemistry, we compare previously established global sea surface iodide parameterisations with new, region-specific parameterisations based on the new iodide observations. This study shows that regional changes in salinity and sea surface temperature play a role in surface seawater iodide estimation. Sea-air fluxes of HOI and I2, calculated from the atmospheric ozone and seawater iodide concentrations (observed and predicted), failed to adequately explain the detected IO in this region. This discrepancy highlights the need to measure direct fluxes of inorganic and organic iodine species in the marine environment. Amongst other potential drivers of reactive iodine chemistry investigated, chlorophyll-a showed a significant correlation with atmospheric IO (R = 0.7 above the 99 % significance level) to the north of the polar front. This correlation might be indicative of a biogenic control on iodine sources in this region.

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“…However, in its vapor phase, it is a highly mobile gas which is toxic and easily spills into the air [ 10 ]. Recently, a paper about the quantitative detection of iodine in the stratosphere was reported wherein a link between air quality and ozone loss was established [ 11 ]. As the ozone destruction potential of iodine is 600 times more compared to that of chlorine, harmful effects of iodine are detrimental to the environment.…”

Section: Introductionmentioning

confidence: 99%

Metal Organic Framework-Polyethersulfone Composite Membrane for Iodine Capture

Tang

Lee

et al. 2020

Polymers

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A variety of metal organic frameworks (MOFs) were synthesized and evaluated for their iodine adsorption capacity. Out of the MOFs tested, ZIF-8 showed the most promising result with an iodine vapor uptake of 876.6 mg/g. ZIF-8 was then incorporated into a polymer, polyethersulfone (PES), at different proportions to prepare mixed matrix membranes (MMMs), which were then used to perform further iodine adsorption experiments. With a mixing ratio of 40 wt % of ZIF-8, the iodine adsorption capacity reached 1387.6 mg/g, wherein an astounding 60% improvement in adsorption was seen with the MMMs prepared compared to the original ZIF-8 powder.

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Quantitative detection of iodine in the stratosphere

Cited by 94 publications

References 62 publications

Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

Estimation of Reactive Inorganic Iodine Fluxes in the Indian and Southern Ocean Marine Boundary Layer

Metal Organic Framework-Polyethersulfone Composite Membrane for Iodine Capture

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