High-volume bulk aerosol samples have been collected at American Samoa (14.25¿S, 170.58¿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) SO=4 and NO-3. 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 SO=4, 0.0229 for MSA, 0.114 for NO-3, and 5.1 for Na+. Nss SO=4 and MSA are strongly linearly correlated in these 171 samples (r 2=0.66) and the regression intercept does not differ significantly from zero. The geometric mean (GM) nss SO=4/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&sgr; analytical uncertainties of 5% for MSA and SO=4 and 2% for Na+.