The Chemistry of Mercury in the Stratosphere
Abstract Mercury, a global contaminant, enters the stratosphere through convective uplift, but its chemical cycling in the stratosphere is unknown. We report the first model of stratospheric mercury chemistry based on a novel photosensitized oxidation mechanism. We find two very distinct Hg chemical...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2022-06-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2022GL097953 |
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| author | Alfonso Saiz‐Lopez A. Ulises Acuña Anoop S. Mahajan Juan Z. Dávalos Wuhu Feng Daniel Roca‐Sanjuán Javier Carmona‐García Carlos A. Cuevas Douglas E. Kinnison Juan Carlos Gómez Martín Joseph S. Francisco John M. C. Plane |
| author_facet | Alfonso Saiz‐Lopez A. Ulises Acuña Anoop S. Mahajan Juan Z. Dávalos Wuhu Feng Daniel Roca‐Sanjuán Javier Carmona‐García Carlos A. Cuevas Douglas E. Kinnison Juan Carlos Gómez Martín Joseph S. Francisco John M. C. Plane |
| author_sort | Alfonso Saiz‐Lopez |
| collection | DOAJ |
| description | Abstract Mercury, a global contaminant, enters the stratosphere through convective uplift, but its chemical cycling in the stratosphere is unknown. We report the first model of stratospheric mercury chemistry based on a novel photosensitized oxidation mechanism. We find two very distinct Hg chemical regimes in the stratosphere: in the upper stratosphere, above the ozone maximum concentration, Hg0 oxidation is initiated by photosensitized reactions, followed by second‐step chlorine chemistry. In the lower stratosphere, ground‐state Hg0 is oxidized by thermal reactions at much slower rates. This dichotomy arises due to the coincidence of the mercury absorption at 253.7 nm with the ozone Hartley band maximum at 254 nm. We also find that stratospheric Hg oxidation, controlled by chlorine and hydroxyl radicals, is much faster than previously assumed, but moderated by efficient photo‐reduction of mercury compounds. Mercury lifetime shows a steep increase from hours in the upper‐middle stratosphere to years in the lower stratosphere. |
| format | Article |
| id | doaj-art-22e837d5231c4d3da858f004e39fc499 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2022-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-22e837d5231c4d3da858f004e39fc4992025-01-22T14:38:16ZengWileyGeophysical Research Letters0094-82761944-80072022-06-014912n/an/a10.1029/2022GL097953The Chemistry of Mercury in the StratosphereAlfonso Saiz‐Lopez0A. Ulises Acuña1Anoop S. Mahajan2Juan Z. Dávalos3Wuhu Feng4Daniel Roca‐Sanjuán5Javier Carmona‐García6Carlos A. Cuevas7Douglas E. Kinnison8Juan Carlos Gómez Martín9Joseph S. Francisco10John M. C. Plane11Department of Atmospheric Chemistry and Climate Institute of Physical Chemistry Rocasolano CSIC Madrid SpainDepartment of Atmospheric Chemistry and Climate Institute of Physical Chemistry Rocasolano CSIC Madrid SpainCentre for Climate Change Research Indian Institute of Tropical Meteorology Ministry of Earth Sciences Pune IndiaDepartment of Atmospheric Chemistry and Climate Institute of Physical Chemistry Rocasolano CSIC Madrid SpainSchool of Chemistry University of Leeds Leeds UKInstitut de Ciència Molecular Universitat de València València SpainDepartment of Atmospheric Chemistry and Climate Institute of Physical Chemistry Rocasolano CSIC Madrid SpainDepartment of Atmospheric Chemistry and Climate Institute of Physical Chemistry Rocasolano CSIC Madrid SpainAtmospheric Chemistry Observations and Modelling NCAR Boulder CO USAInstituto de Astrofísica de Andalucía CSIC Granada SpainDepartment of Earth and Environmental Science and Department of Chemistry University of Pennsylvania Philadelphia PA USASchool of Chemistry University of Leeds Leeds UKAbstract Mercury, a global contaminant, enters the stratosphere through convective uplift, but its chemical cycling in the stratosphere is unknown. We report the first model of stratospheric mercury chemistry based on a novel photosensitized oxidation mechanism. We find two very distinct Hg chemical regimes in the stratosphere: in the upper stratosphere, above the ozone maximum concentration, Hg0 oxidation is initiated by photosensitized reactions, followed by second‐step chlorine chemistry. In the lower stratosphere, ground‐state Hg0 is oxidized by thermal reactions at much slower rates. This dichotomy arises due to the coincidence of the mercury absorption at 253.7 nm with the ozone Hartley band maximum at 254 nm. We also find that stratospheric Hg oxidation, controlled by chlorine and hydroxyl radicals, is much faster than previously assumed, but moderated by efficient photo‐reduction of mercury compounds. Mercury lifetime shows a steep increase from hours in the upper‐middle stratosphere to years in the lower stratosphere.https://doi.org/10.1029/2022GL097953mercurychemistrystratosphere |
| spellingShingle | Alfonso Saiz‐Lopez A. Ulises Acuña Anoop S. Mahajan Juan Z. Dávalos Wuhu Feng Daniel Roca‐Sanjuán Javier Carmona‐García Carlos A. Cuevas Douglas E. Kinnison Juan Carlos Gómez Martín Joseph S. Francisco John M. C. Plane The Chemistry of Mercury in the Stratosphere Geophysical Research Letters mercury chemistry stratosphere |
| title | The Chemistry of Mercury in the Stratosphere |
| title_full | The Chemistry of Mercury in the Stratosphere |
| title_fullStr | The Chemistry of Mercury in the Stratosphere |
| title_full_unstemmed | The Chemistry of Mercury in the Stratosphere |
| title_short | The Chemistry of Mercury in the Stratosphere |
| title_sort | chemistry of mercury in the stratosphere |
| topic | mercury chemistry stratosphere |
| url | https://doi.org/10.1029/2022GL097953 |
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