During the months of December 1996 and January 1997, aerosol characterization was performed in real-time at Riverside, CA, an inland location approximately 100 km east of the Los Angeles coast. Analysis was performed on a single particle basis with measurements of both particle size and composition. Data were collected throughout the course of five rainstorms. Single particle mass spectra demonstrate that obvious composition changes occur in the aerosol systems as the marine air mass is transported inland. While precipitation scavenging of aerosols was observed, there was a significant relative increase of sea salt particles in the non-scavenged aerosol. Compositionally-resolved particle size distributions also demonstrate real-time changes that occur in the atmospheric aerosol sample. ¿ 1997 American Geophysical Union