Abstract
Temporal measurements of mass concentration and mean volume equivalent diameter of soot particles in diesel exhaust were made simultaneously by a two-wavelength extinction method and a scattering method. It is shown that the soot mass concentration changes dynamically depending on the variation in engine load, while the mean particle size varies within a narrow range centering 150 nm. A theoretical approach to quantify the scattering to absorption ratio of diesel soot particles is proposed whereby the transmittance values measured at two wavelengths and electron micrographs of sampled soot particles are incorporated into the soot aggregate scattering theory.
