FREQUENCY-DISTRIBUTIONS OF PM(10) CHEMICAL-COMPONENTS AND THEIR SOURCES

The frequency distributions and statistical properties of the chemical components of PM(10) and their sources in the South Coast Air Basin ( SoCAB) were analyzed from several year-long studies. The non- reactive aerosol components of PM(10) have approximate ly log normal frequency distributions and constant values of geometric standard deviation (GS D) regardless of source type and location. Some major components of PM (10) behave differently from the total mass, resulting in a decreased variability for-the total mass compared with the variability of the ma jor components. The frequency distributions of the source contribution s, as computed from a chemical mass balance(CMB) receptor model, showe d approximately log normal behavior for most sources. There is evidenc e of bimodal frequency distributions for the crustal source of PM(10) at certain locations, possibly indicating contributions from several d ifferent sources that have similar chemical profiles.