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Saiz-Lopez, A, Plane, JMC orcid.org/0000-0003-3648-6893, Cuevas, CA et al. (3 more authors) (2016) Nighttime atmospheric chemistry of iodine. Atmospheric Chemistry and Physics, 16 (24). pp. 15593-15604. ISSN 1680-7316
Abstract
Little attention has so far been paid to the nighttime atmospheric chemistry of iodine species. Current atmospheric models predict a buildup of HOI and I₂ during the night that leads to a spike of IO at sunrise, which is not observed by measurements. In this work, electronic structure calculations are used to survey possible reactions that HOI and I₂ could undergo at night in the lower troposphere, and hence reduce their nighttime accumulation. The new reaction NO₃+ HOI → IO + HNO₃ is proposed, with a rate coefficient calculated from statistical rate theory over the temperature range 260–300 K and at a pressure of 1000 hPa to be k(T) = 2.7 × 10¯¹² (300 K/T)²·⁶⁶ cm³ molecule¯¹ s¯¹. This reaction is included in two atmospheric models, along with the known reaction between I₂ and NO₃, to explore a new nocturnal iodine radical activation mechanism. The results show that this iodine scheme leads to a considerable reduction of nighttime HOI and I₂, which results in the enhancement of more than 25 % of nighttime ocean emissions of HOI +I₂ and the removal of the anomalous spike of IO at sunrise. We suggest that active nighttime iodine can also have a considerable, so far unrecognized, impact on the reduction of the NO₃ radical levels in the marine boundary layer (MBL) and hence upon the nocturnal oxidizing capacity of the marine atmosphere. The effect of this is exemplified by the indirect effect on dimethyl sulfide (DMS) oxidation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) Author(s), 2016. This work is distributed under the Creative Commons Attribution 3.0 License. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Jan 2017 16:32 |
Last Modified: | 25 Sep 2018 15:02 |
Published Version: | https://doi.org/10.5194/acp-16-15593-2016 |
Status: | Published |
Publisher: | European Geosciences Union (EGU) |
Identification Number: | 10.5194/acp-16-15593-2016 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:110686 |
Available Versions of this Item
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Iodine chemistry after dark. (deposited 25 Sep 2018 15:01)
- Nighttime atmospheric chemistry of iodine. (deposited 16 Jan 2017 16:32) [Currently Displayed]