The inhomogeneity of the aerosol chemistry for a 4-year data set from the geographic central region of Alaska expressed through loading of principal components provides provisional multivariate statistical identification for components of nonanthropogenic (apparently natural) sources of particles. Besides an Al-rich dust which is generally present but is slightly elevated in summer months, a marine sea-salt component of aerosol is detectable as well as a Br component. The marine sea-salt component was most evident when air over the ocean flowed behind the Alaska mountain range barrier from the Bering Sea and entered into the flat river floodplain of interior Alaska, undergoing little or no orographic lifting in the process. During such flow patterns, marine components such as sodium, chlorine, potassium, and selenium are enhanced by up to a factor of 10 from average, but these very components are also attenuated strongly during forced overmountain ''chinook'' flow. We hypothesize that the sea-salt deficiency for the latter flow is due to nucleation and rainout on the windward side of the Alaska mountain range and calculate that this is plausible. Chlorine in sea salt is evidently volatilized and released from the particulate phase, leading to a severalfold depletion relative to sodium aerosol during incursions of acid-rich pollution aerosol from the Arctic. Bromine in aerosol in the central geographic region in Alaska undergoes a large (¿10) enhancement each year in late March to early April in affiliation with flow of air from the Arctic. ¿ American Geophysical Union 1991