ATMOSPHERIC AEROSOL TRACE-ELEMENT CHEMISTRY AT MAUNA-LOA-OBSERVATORY .1. 1979-1985

Aerosol samples were collected at the Mauna Loa Observatory in Hawaii from February 1979 to May 1985. The samples were analyzed via instrume ntal 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 cre ating a ''dust season.'' Of the 47 elements detected, 37 have a notabl y higher mass average during the dust season, The data record is explo red using enrichment factors, principal component analysis, and chemic al mass balances (receptor modeling), The crustal material accounts fo r 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 th e natural variation dominating the principal component analysis by des cribing greater than 60% of the overall variance. Particulate sulfate is another major component accounting for 10-40% of the aerosol mass d uring dust seasons and 60-75% of the mass during nondust seasons. Part iculate sulfate can be derived from crustal material and sea salt. Ant hropogenic activity also can produce particulate sulfate or its precur sors that can adhere to the surface of crustal material that travels o ver a polluted area. Minor components in the downslope winds are marin e sea-salt aerosol contributing less than 3% of the aerosol mass durin g 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 therefor e no carbon-based aerosols such as soot or organic aerosols are consid ered in the total aerosol mass.)