Sources and chemistry of PM10 aerosol in Santa Barbara County, CA

PM10 aerosols were collected during 1989 every sixth day at six sites in Santa Barbara County, CA. Samples were analyzed for sulfate, nitrate, and ammonium ions, carbon, and elements. Chemical Mass Balance (CMB) receptor modeling was conducted to determine the sources of PM 10. Motor vehicles, road dust, and marine aerosol accounted for 30–42, 25–27, and 18–23% of PM10, respectively, at three urban sites: Santa Barbara, Santa Maria, and Santa Ynez. The marine contribution was 55–63% of PM10 at two marine background sites. Fresh marine aerosols were characterized by low levels of urban emissions, low concentrations of secondary sulfate and nitrate, and generally higher levels of acidity. Conversely, marine aerosols aged by contact with land-based emissions had higher concentrations of secondary ammonium sulfate and nitrate.