Partitioning of organic matter (i.e., solvent-extractable) was examined between ambient aerosols and rainwater particulate and dissolved phases. A rainfall event during April 10–11, 1982, was sampled in combination with 24-hour high-volume aerosol samples (before, during, and after the storm) at West Los Angeles and Pasadena, CA. Solvent-extractable organic matter (> C15) was analyzed for total neutral and acidic components. These extract fractions were quantified by high-resolution gas chromatography and then screened for hydrocarbons, ketones, carboxylic acids as esters, alcohols, and polynuclear aromatic hydrocarbons (PAH) by high-resolution gas chromatography / mass spectrometry. Comparisons of the total mass loadings and chemical speciation were made between the total ambient aerosols and the filtered rainwater (with particles of diameters 0.22 μm). Both rain particles and ambient aerosols had significant levels of plant wax...