Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century
The NO x (NO and NO 2 ) and HO x (OH and HO 2 ) budgets of the atmosphere exert a major influence on atmospheric composition, controlling removal of primary pollutants and formation of a wide range of secondary products, including ozone, that can influence human health and climate. However, there re...
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Online Access: | https://doi.org/10.5194/acp-17-8269-2017 https://www.atmos-chem-phys.net/17/8269/2017/ |
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ftcopernicus:oai:publications.copernicus.org:acp55385 2023-05-15T15:12:19+02:00 Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century Newland, Mike J. Martinerie, Patricia Witrant, Emmanuel Helmig, Detlev Worton, David R. Hogan, Chris Sturges, William T. Reeves, Claire E. 2018-09-09 application/pdf https://doi.org/10.5194/acp-17-8269-2017 https://www.atmos-chem-phys.net/17/8269/2017/ eng eng doi:10.5194/acp-17-8269-2017 https://www.atmos-chem-phys.net/17/8269/2017/ eISSN: 1680-7324 Text 2018 ftcopernicus https://doi.org/10.5194/acp-17-8269-2017 2019-12-24T09:51:18Z The NO x (NO and NO 2 ) and HO x (OH and HO 2 ) budgets of the atmosphere exert a major influence on atmospheric composition, controlling removal of primary pollutants and formation of a wide range of secondary products, including ozone, that can influence human health and climate. However, there remain large uncertainties in the changes to these budgets over recent decades. Due to their short atmospheric lifetimes, NO x and HO x are highly variable in space and time, and so the measurements of these species are of limited value for examining long-term, large-scale changes to their budgets. Here, we take an alternative approach by examining long-term atmospheric trends of alkyl nitrates, the production efficiency of which is dependent on the atmospheric [NO] ∕ [HO 2 ] ratio. We derive long-term trends in the alkyl nitrates from measurements in firn air from the NEEM site, Greenland. Their mixing ratios increased by a factor of 3–5 between the 1970s and 1990s. This was followed by a steep decline to the sampling date of 2008. Moreover, we examine how the trends in the alkyl nitrates compare to similarly derived trends in their parent alkanes (i.e. the alkanes which, when oxidised in the presence of NO x , lead to the formation of the alkyl nitrates). The ratios of the alkyl nitrates to their parent alkanes increased from around 1970 to the late 1990s. This is consistent with large changes to the [NO] ∕ [HO 2 ] ratio in the Northern Hemisphere atmosphere during this period. Alternatively, they could represent changes to concentrations of the hydroxyl radical, OH, or to the transport time of the air masses from source regions to the Arctic. Text Arctic Greenland Human health Copernicus Publications: E-Journals Arctic Greenland Atmospheric Chemistry and Physics 17 13 8269 8283 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The NO x (NO and NO 2 ) and HO x (OH and HO 2 ) budgets of the atmosphere exert a major influence on atmospheric composition, controlling removal of primary pollutants and formation of a wide range of secondary products, including ozone, that can influence human health and climate. However, there remain large uncertainties in the changes to these budgets over recent decades. Due to their short atmospheric lifetimes, NO x and HO x are highly variable in space and time, and so the measurements of these species are of limited value for examining long-term, large-scale changes to their budgets. Here, we take an alternative approach by examining long-term atmospheric trends of alkyl nitrates, the production efficiency of which is dependent on the atmospheric [NO] ∕ [HO 2 ] ratio. We derive long-term trends in the alkyl nitrates from measurements in firn air from the NEEM site, Greenland. Their mixing ratios increased by a factor of 3–5 between the 1970s and 1990s. This was followed by a steep decline to the sampling date of 2008. Moreover, we examine how the trends in the alkyl nitrates compare to similarly derived trends in their parent alkanes (i.e. the alkanes which, when oxidised in the presence of NO x , lead to the formation of the alkyl nitrates). The ratios of the alkyl nitrates to their parent alkanes increased from around 1970 to the late 1990s. This is consistent with large changes to the [NO] ∕ [HO 2 ] ratio in the Northern Hemisphere atmosphere during this period. Alternatively, they could represent changes to concentrations of the hydroxyl radical, OH, or to the transport time of the air masses from source regions to the Arctic. |
format |
Text |
author |
Newland, Mike J. Martinerie, Patricia Witrant, Emmanuel Helmig, Detlev Worton, David R. Hogan, Chris Sturges, William T. Reeves, Claire E. |
spellingShingle |
Newland, Mike J. Martinerie, Patricia Witrant, Emmanuel Helmig, Detlev Worton, David R. Hogan, Chris Sturges, William T. Reeves, Claire E. Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
author_facet |
Newland, Mike J. Martinerie, Patricia Witrant, Emmanuel Helmig, Detlev Worton, David R. Hogan, Chris Sturges, William T. Reeves, Claire E. |
author_sort |
Newland, Mike J. |
title |
Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
title_short |
Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
title_full |
Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
title_fullStr |
Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
title_full_unstemmed |
Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century |
title_sort |
changes to the chemical state of the northern hemisphere atmosphere during the second half of the twentieth century |
publishDate |
2018 |
url |
https://doi.org/10.5194/acp-17-8269-2017 https://www.atmos-chem-phys.net/17/8269/2017/ |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland Human health |
genre_facet |
Arctic Greenland Human health |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-17-8269-2017 https://www.atmos-chem-phys.net/17/8269/2017/ |
op_doi |
https://doi.org/10.5194/acp-17-8269-2017 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
17 |
container_issue |
13 |
container_start_page |
8269 |
op_container_end_page |
8283 |
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1766343020274253824 |