SOURCES AND CHEMISTRY OF PM(10) AEROSOL IN SANTA-BARBARA COUNTY, CA

PM(10) aerosols were collected during 1989 every sixth day at six site s in Santa Barbara County, CA. Samples were analyzed for sulfate, nitr ate, and ammonium ions, carbon, and elements. Chemical Mass Balance (C MB) receptor modeling was conducted to determine the sources of PM(10) . Motor vehicles, road dust, and marine aerosol accounted for 30-42, 2 5-27, and 18-23% of PM(10), respectively, at three urban sites: Santa Barbara, Santa Maria, and Santa Ynez. The marine contribution was 55-6 3% of PM(10) at two marine background sites. Fresh marine aerosols wer e characterized by low levels of urban emissions, low concentrations o f secondary sulfate and nitrate, and generally higher levels of acidit y. Conversely, marine aerosols aged by contact with land-based emissio ns had higher concentrations of secondary ammonium sulfate and nitrate .