Frequency Distributions of PM10 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 nonreactive aerosol components of PM 10 have approximately log normal frequency distributions and constant values of geometric standard deviation (GSD) 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 major components. The frequency distributions of the source contributions, as computed from a chemical mass balance (CMB) receptor model, showed approximately log normal behavior for most sources