RECEPTOR MODELING OF THE FINE AEROSOL AT A RESIDENTIAL LOS-ANGELES SITE

Receptor modeling on ambient aerosol and air quality data collected at Duarte, CA (a residential site near Los Angeles), in 1983 and 1987-1988 was carried out. A significant change in the ambient concentrations of SO42-, Al, Si, Mn, Fe, Pb, Br, volatile and organic carbon and fine particle (FP) mass took place from 1983 to 1987-1988. A drastic reduction (approximately 80%) of the ambient Pb and Br concentrations took place as the lead content and the usage of leaded gasoline decreased in the Los Angeles Basin during that period. A day-of-the-week analysis indicated that both crustal (Si, Ca, Fe) and transportation (Pb, CO, organic carbon and black carbon) related pollutants exhibit significantly different concentrations between weekdays and weekends of 1987-1988. This indicates that loadings of suspended soil dust are more affected by anthropogenic activities than meteorological patterns. In contrast, sulfate and volatile carbon concentrations seem to be insensitive to that cycle indicating that other sources/processes can be responsible for the ambient levels of these pollutants, Principal component analysis of aerosol and air quality data showed that the major contributions to the variance of the ambient aerosol loadings come-from soil, motor vehicles and sulfates.