CCSEM investigation of respirable quartz in air samples collected during power plant maintenance activities

► A improved method has been developed to measure respirable quartz in coal fly ash (CFA) using computer-controlled SEM. ► CCSEM and X-ray diffraction (XRD) were used to measure respirable quartz in CFA collected at two power plants. ► CCSEM and XRD were in good agreement only for samples collected using cyclone-filtered air samplers.