Instantaneous dust exposure monitors

This is a review of investigations conducted to evaluate portable, direct reading instruments employing the principles of light scattering and the attenuation of beta-rays to measure the respirable mass concentration of airborne particulates. Data are presented on comparative measurements obtained with several different models of beta-ray attenuation instruments manufactured by the GCA Corporation and light scattering instruments manufactured by GCA Corporation, USA, Ernst Leitz, GmbH, Germany, Rotheroe and Mitchell, England, and Sibata Chemical Apparatus Manufacturing Company, Ltd., Japan, using aerosols of coal, limestone, Arizona road dust, and silica. The effect of aerosol parameters (concentration, size distribution, index of refraction) on instrument calibration and precision are discussed.