Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations
While the hydroxyl radical ( <mo>•</mo> OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of <mo>•</mo> OH on/in snow and ice. Here we measure the formation rate, lifetime, and c...
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ftdoajarticles:oai:doaj.org/article:f89fdc353ffa4581bbd23c6d78738afe 2023-05-15T16:28:43+02:00 Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations Z. Chen L. Chu E. S. Galbavy K. Ram C. Anastasio 2016-08-01T00:00:00Z https://doi.org/10.5194/acp-16-9579-2016 https://doaj.org/article/f89fdc353ffa4581bbd23c6d78738afe EN eng Copernicus Publications https://www.atmos-chem-phys.net/16/9579/2016/acp-16-9579-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-9579-2016 1680-7316 1680-7324 https://doaj.org/article/f89fdc353ffa4581bbd23c6d78738afe Atmospheric Chemistry and Physics, Vol 16, Pp 9579-9590 (2016) Physics QC1-999 Chemistry QD1-999 article 2016 ftdoajarticles https://doi.org/10.5194/acp-16-9579-2016 2022-12-31T15:24:39Z While the hydroxyl radical ( <mo>•</mo> OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of <mo>•</mo> OH on/in snow and ice. Here we measure the formation rate, lifetime, and concentration of <mo>•</mo> OH for illuminated polar snow samples studied in the laboratory and in the field. Laboratory studies show that <mo>•</mo> OH kinetics and steady-state concentrations are essentially the same for a given sample studied as ice and liquid; this is in contrast to other photooxidants, which show a concentration enhancement in ice relative to solution as a result of kinetic differences in the two phases. The average production rate of <mo>•</mo> OH in samples studied at Summit, Greenland, is 5 times lower than the average measured in the laboratory, while the average <mo>•</mo> OH lifetime determined in the field is 5 times higher than in the laboratory. These differences indicate that the polar snows we studied in the laboratory are affected by contamination, despite significant efforts to prevent this; our results suggest similar contamination may be a widespread problem in laboratory studies of ice chemistry. Steady-state concentrations of <mo>•</mo> OH in clean snow studied in the field at Summit, Greenland, range from (0.8 to 3) × 10 −15 M, comparable to values reported for midlatitude cloud and fog drops, rain, and deliquesced marine particles, even though impurity concentrations in the snow samples are much lower. Partitioning of firn air <mo>•</mo> OH to the snow grains will approximately double the steady-state concentration of snow-grain hydroxyl radical, leading to an average [ <mo>•</mo> OH] in near-surface, summer Summit snow of approximately 4 × 10 −15 M. At this concentration, the <mo>•</mo> OH-mediated lifetimes of organics and bromide in Summit snow grains are approximately 3 days and 7 ... Article in Journal/Newspaper Greenland Directory of Open Access Journals: DOAJ Articles Greenland Atmospheric Chemistry and Physics 16 15 9579 9590 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 Z. Chen L. Chu E. S. Galbavy K. Ram C. Anastasio Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
While the hydroxyl radical ( <mo>•</mo> OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of <mo>•</mo> OH on/in snow and ice. Here we measure the formation rate, lifetime, and concentration of <mo>•</mo> OH for illuminated polar snow samples studied in the laboratory and in the field. Laboratory studies show that <mo>•</mo> OH kinetics and steady-state concentrations are essentially the same for a given sample studied as ice and liquid; this is in contrast to other photooxidants, which show a concentration enhancement in ice relative to solution as a result of kinetic differences in the two phases. The average production rate of <mo>•</mo> OH in samples studied at Summit, Greenland, is 5 times lower than the average measured in the laboratory, while the average <mo>•</mo> OH lifetime determined in the field is 5 times higher than in the laboratory. These differences indicate that the polar snows we studied in the laboratory are affected by contamination, despite significant efforts to prevent this; our results suggest similar contamination may be a widespread problem in laboratory studies of ice chemistry. Steady-state concentrations of <mo>•</mo> OH in clean snow studied in the field at Summit, Greenland, range from (0.8 to 3) × 10 −15 M, comparable to values reported for midlatitude cloud and fog drops, rain, and deliquesced marine particles, even though impurity concentrations in the snow samples are much lower. Partitioning of firn air <mo>•</mo> OH to the snow grains will approximately double the steady-state concentration of snow-grain hydroxyl radical, leading to an average [ <mo>•</mo> OH] in near-surface, summer Summit snow of approximately 4 × 10 −15 M. At this concentration, the <mo>•</mo> OH-mediated lifetimes of organics and bromide in Summit snow grains are approximately 3 days and 7 ... |
format |
Article in Journal/Newspaper |
author |
Z. Chen L. Chu E. S. Galbavy K. Ram C. Anastasio |
author_facet |
Z. Chen L. Chu E. S. Galbavy K. Ram C. Anastasio |
author_sort |
Z. Chen |
title |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_short |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_full |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_fullStr |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_full_unstemmed |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_sort |
hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-9579-2016 https://doaj.org/article/f89fdc353ffa4581bbd23c6d78738afe |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Atmospheric Chemistry and Physics, Vol 16, Pp 9579-9590 (2016) |
op_relation |
https://www.atmos-chem-phys.net/16/9579/2016/acp-16-9579-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-9579-2016 1680-7316 1680-7324 https://doaj.org/article/f89fdc353ffa4581bbd23c6d78738afe |
op_doi |
https://doi.org/10.5194/acp-16-9579-2016 |
container_title |
Atmospheric Chemistry and Physics |
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16 |
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15 |
container_start_page |
9579 |
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9590 |
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