Chemical composition of aerosols collected over the tropical North Atlantic Ocean

Ambient aerosol samples were collected over the tropical northern Atlantic Ocean during the month of April 1996 onboard the R/V Seward Johnson. Dichotomous high-volume collector samples were analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations were determin...

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Published in:Journal of Geophysical Research: Atmospheres
Main Authors: Johansen, Anne M., Siefert, Ronald L., Hoffmann, Michael R.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Geophysical Union 2000
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Online Access:https://doi.org/10.1029/2000JD900024
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spelling ftcaltechauth:oai:authors.library.caltech.edu:3yph7-8n327 2024-09-15T18:24:13+00:00 Chemical composition of aerosols collected over the tropical North Atlantic Ocean Johansen, Anne M. Siefert, Ronald L. Hoffmann, Michael R. 2000-06-27 https://doi.org/10.1029/2000JD900024 unknown American Geophysical Union https://doi.org/10.1029/2000JD900024 oai:authors.library.caltech.edu:3yph7-8n327 eprintid:59447 resolverid:CaltechAUTHORS:20150812-113743698 info:eu-repo/semantics/openAccess Other Journal of Geophysical Research D, 105(D12), 15277-15312, (2000-06-27) info:eu-repo/semantics/article 2000 ftcaltechauth https://doi.org/10.1029/2000JD900024 2024-08-06T15:34:58Z Ambient aerosol samples were collected over the tropical northern Atlantic Ocean during the month of April 1996 onboard the R/V Seward Johnson. Dichotomous high-volume collector samples were analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations were determined upon return to the laboratory. Data are analyzed with the aid of enrichment factor, principal component, and weighted multiple linear regression analyses. Average mineral aerosol concentrations amounted to 19.3±16.4 μg m^(−3) whereby the chemical characteristics and air mass back trajectories indicated the dust to be of a typical shale composition and Saharan origin. Calcite accounted for 3.0 and 7.9% of the mineral aerosol during the first and second halves of the cruise, respectively. Total iron concentrations (averaging 0.84±0.61 μg m^(−3)) are crustally derived, of which 0.51±0.56% is readily released as Fe(II). Eighty-six percent of this Fe(II) is present in the fine (<3 μm diameter) aerosol fraction and correlates with NSS-SO_4^(2−) and oxalate. Approximately 23% of the measured NSS-SO_4^(2−) in both size fractions appears to be biogenically derived, and the rest is of anthropogenic nature. Biogenic SO_4^(2−) /methanesulfonic acid (MSA) ratios could not be easily extracted by employing a multiple linear regression analysis analogous to that of Johansen et al. [1999], possibly due to the varying characteristics of the aerosol chemistry and air temperature during the cruise. Because of the presence of anthropogenic SO_4^(2−), the non-sea-salt (NSS)- SO_4^(2−)/MSA ratio, 37.4±6.4, is elevated over what would be expected if the NSS - SO_4^(2−) were purely biogenic. Cl^− depletion is seen in all samples and averages 18.3±9.1%. The release of Cl from the aerosol phase appears to occur through acid displacement reactions with primarily HNO_3 in the coarse and H_2SO_4 in the fine fraction. © 2000 American Geophysical Union. Received August 19, 1999; revised November 16, 1999; accepted ... Article in Journal/Newspaper North Atlantic Caltech Authors (California Institute of Technology) Journal of Geophysical Research: Atmospheres 105 D12 15277 15312
institution Open Polar
collection Caltech Authors (California Institute of Technology)
op_collection_id ftcaltechauth
language unknown
description Ambient aerosol samples were collected over the tropical northern Atlantic Ocean during the month of April 1996 onboard the R/V Seward Johnson. Dichotomous high-volume collector samples were analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations were determined upon return to the laboratory. Data are analyzed with the aid of enrichment factor, principal component, and weighted multiple linear regression analyses. Average mineral aerosol concentrations amounted to 19.3±16.4 μg m^(−3) whereby the chemical characteristics and air mass back trajectories indicated the dust to be of a typical shale composition and Saharan origin. Calcite accounted for 3.0 and 7.9% of the mineral aerosol during the first and second halves of the cruise, respectively. Total iron concentrations (averaging 0.84±0.61 μg m^(−3)) are crustally derived, of which 0.51±0.56% is readily released as Fe(II). Eighty-six percent of this Fe(II) is present in the fine (<3 μm diameter) aerosol fraction and correlates with NSS-SO_4^(2−) and oxalate. Approximately 23% of the measured NSS-SO_4^(2−) in both size fractions appears to be biogenically derived, and the rest is of anthropogenic nature. Biogenic SO_4^(2−) /methanesulfonic acid (MSA) ratios could not be easily extracted by employing a multiple linear regression analysis analogous to that of Johansen et al. [1999], possibly due to the varying characteristics of the aerosol chemistry and air temperature during the cruise. Because of the presence of anthropogenic SO_4^(2−), the non-sea-salt (NSS)- SO_4^(2−)/MSA ratio, 37.4±6.4, is elevated over what would be expected if the NSS - SO_4^(2−) were purely biogenic. Cl^− depletion is seen in all samples and averages 18.3±9.1%. The release of Cl from the aerosol phase appears to occur through acid displacement reactions with primarily HNO_3 in the coarse and H_2SO_4 in the fine fraction. © 2000 American Geophysical Union. Received August 19, 1999; revised November 16, 1999; accepted ...
format Article in Journal/Newspaper
author Johansen, Anne M.
Siefert, Ronald L.
Hoffmann, Michael R.
spellingShingle Johansen, Anne M.
Siefert, Ronald L.
Hoffmann, Michael R.
Chemical composition of aerosols collected over the tropical North Atlantic Ocean
author_facet Johansen, Anne M.
Siefert, Ronald L.
Hoffmann, Michael R.
author_sort Johansen, Anne M.
title Chemical composition of aerosols collected over the tropical North Atlantic Ocean
title_short Chemical composition of aerosols collected over the tropical North Atlantic Ocean
title_full Chemical composition of aerosols collected over the tropical North Atlantic Ocean
title_fullStr Chemical composition of aerosols collected over the tropical North Atlantic Ocean
title_full_unstemmed Chemical composition of aerosols collected over the tropical North Atlantic Ocean
title_sort chemical composition of aerosols collected over the tropical north atlantic ocean
publisher American Geophysical Union
publishDate 2000
url https://doi.org/10.1029/2000JD900024
genre North Atlantic
genre_facet North Atlantic
op_source Journal of Geophysical Research D, 105(D12), 15277-15312, (2000-06-27)
op_relation https://doi.org/10.1029/2000JD900024
oai:authors.library.caltech.edu:3yph7-8n327
eprintid:59447
resolverid:CaltechAUTHORS:20150812-113743698
op_rights info:eu-repo/semantics/openAccess
Other
op_doi https://doi.org/10.1029/2000JD900024
container_title Journal of Geophysical Research: Atmospheres
container_volume 105
container_issue D12
container_start_page 15277
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