"Feasibility studies for measuring size distributions of aerosols and particulates in the off gas from an oil shale retort have been conducted. A transmissiometer to measure extinction of a laser beam has been constructed. The extinction of the beam was measured after it passed through oil shale off gas. This extinction data combined with analysis using Andersen impactor samples yielded useful information on the size and mass distribution of aerosols and particulates in off gas. Recommendations for further studies using optical electronic instruments are outlined."