The Generation and Characterization of a Respirable Aerosol of Chrysotile Asbestos for Chronic Inhalation Studies

Abstract

A chrysotile asbestos aerosol generator capable of producing respirable aerosol concentrations of the order of 25 µg/liter over prolonged periods of time has been developed. The coefficient of variation of the aerosol concentrations from day to day is of the order of 20%. The aerosol is adequately dispersed for inhalation studies, but characterization of the fibers in terms of lengths and diameters is exceedingly difficult. The electron micrographs show that the fibers are so irregular, clumped, and curved that determination of a meaningful aspect ratio (diameter/length) is not possible. Aerodynamic particle size distributions were determined with the aid of the Andersen cascade impactor to have median values of 1 to 3 µm.