[Measurement of free silica concentration in the dust by small X-ray diffractometer].

X-ray diffraction method was applied to measure free silica concentration in the dust and the procedure of analysis have been established. The filter used was the polyvinyl chloride filter. Good linear relationship was shown to exist between the amount of silica and the intensity of its diffracted rays (r = 0.99). The standard deviation of repeated tests was 3.199%. The coefficient of variation was 4.43. An amount of 0.015 mg silica collected on the filter (d = 9 mm) can be detected. This method is suitable for monitoring and investigating silica contents in labour hygiene studies.