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Non-sea-salt sulfate and methanesulfonate at American SamoaHigh-volume bulk aerosol samples have been collected at American Samoa (14.25 deg S, 170.58 deg W) on a semicontinuous basis since the system was erected as part of the Sea/Air Exchange Program (SEAREX) in March 1983. In this report we consider those samples collected through May 6, 1992. For most of this period the sample filters were changed once a week. However, during November 1989 and from May 10 to June 10, 1990, in conjunction with the aircraft missions of the NASA Global Backscatter Experiment (GLOBE), the filters were changed daily. All of the samples were analyzed for nonsea-salt (nss) SO4(2-) and NO3(-). Analyses for methanesulfonate (MSA) include all of the 53 daily samples, 22 weekly samples from March 19, 1983, through April 12, 1984, and 96 weekly samples from January 3, 1990, through May 6, 1992. The mean concentrations (in micrograms per cubic meter) were 0.37 for nss SO4(2-), 0.0229 for MSA, 0.114 for NO3(-), and 5.1 for Na(+). Nss SO4(2-) and MSA are strongly linearly correlated in these 171 samples (r(exp 2) = 0.66) and the regression intercept does not differ significantly from zero. The geometric mean (GM) nss SO4(2-)/MSA ratio, 18.1 +/- 0.9 (where +/- indicates the 95% confidence interval of the GM) is about 7% higher than had previously been reported for this station. The ratio exhibits no significant seasonal variation. Although the ratio appeared to be significantly lower in the May - June 1990 daily samples (GM = 15.3 +/- 1.2), a further examination of the results indicated that the variance of the measured ratios from 18.1 (the GM for the whole data set) was attributable almost exclusively to the typical random errors in the analyses as determined from the 1 sigma analytical uncertainties of 5% for MSA and SO4(2-) and 2% for Na(+).
Document ID
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Savoie, Dennis L.
(Miami Univ. Miami, FL, United States)
Prospero, Joseph M.
(Miami Univ. Miami, FL, United States)
Arimoto, Richard
(Center for Atmospheric Studies, Rhode Island Univ. Narragansett, RI, United States)
Duce, Robert
(Texas A&M Univ. College Station, TX, United States)
Date Acquired
August 16, 2013
Publication Date
February 20, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: D2
ISSN: 0148-0227
Subject Category
Environment Pollution
Accession Number
Funding Number(s)
Distribution Limits

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