Variation of composition with particle size in coal liquid aerosols generated for inhalation toxicology studies.

The chemical composition and microbial mutagenicity of aerosols generated by nebulizing two coal oils (solvent refined coal [SRC]-I process solvent [PS] and SRC-II heavy distillate) were found to vary with particle size. Significant quantities of the most volatile components of PS were also present as vapors. Evaporation and condensation processes in oil deposited on surfaces as well as in the aerosol are believed to be important in determining the observed composition changes. Complete physical and chemical characterization of the aerosol should be included in inhalation studies of complex materials since the animals may be exposed to material of quite different composition than that placed in the generator initially.