Aerosol samples were collected at the Mauna Loa Observatory in Hawaii from February 1979 to May 1985. The samples were analyzed via instrumental neutron activation analysis (INAA) for up to 47 elements and via ion chromatography for sulfate. The data are dominated by crustal dust that arrives via long-range transport from Asia each spring, thus creating a ''dust season.'' Of the 47 elements detected, 37 have a notably higher mass average during the dust season. The data record is explored using enrichment factors, principal component analysis, and chemical mass balances (receptor modeling). The crustal material accounts for 60--70% of the overall aerosol mass during dust seasons, yet only 15--20% during nondust seasons. It is by far the largest contributor to the natural variation dominating the principal component analysis by describing greater than 60% of the overall variance. Particulate sulfate is another major component accounting for 10--40% of the aerosol mass during dust seasons and 60--75% of the mass during nondust seasons. Particulate sulfate can be derived from crustal material and sea salt. Anthropogenic activity also can produce particulate sulfate or its precursors that can adhere to the surface of crustal material that travels over a polluted area. Minor components in the downslope winds are marine sea-salt aerosol contributing less than 3% of the aerosol mass during the dust season and 5--6% during the nondust season. Local basalt is considered to contribute less than 2% during the dust season and 3--4% during the nondust season. (Carbon mass is not determined and therefore no carbon-based aerosols such as soot or organic aerosols are considered in the total aerosol mass.) ¿ American Geophysical Union 1995