This study was performed in a diatomite factory located at Pohang City, Kyeongsangbuk-Do. The major objectives were to evaluate. sampling and analytical methods of diatomaceous earth dust.
Concentrations of total and respirable diatomaceous earth dust were measured. Size distribution of dust was analyzed by a personal cascade impactor and the particle size analyzer which is an application of multiple diffraction method. Also crystalline silica in respirable and total dust samples was analyzed quantitatively by X-ray diffraction and Fourie Transform Infrared Spectroscopy(FTIR).
The results were as follows:
The airborne total and respirable dust concentrations, particle size distribution, and cristalline silica(quartz) concentrations showed approximately a log-normal distribution. The means of totaldust concentrations at flour manufacturing, fire brick grinding and packaging processes exceeded the Korean and American Conference of Governmental Industrial Hygienists standards, 10 ㎎/㎥.
The size distribution of diatomaceous earth dust was log-normal and identified as the respirable particle mass and thoracic particle mass. The crystalline silica in respirable and total dust samples was identified to quartz and contained about 10% in those samples.
Finally, it is necessary to study the applicability of multiple diffraction for particle size distribution to compare the ACGIH´s size selective sampling with other materials containing crystalline silica. Also, advanced quantitative study to X-ray diffraction and FTIR methods should be carried out to verify general and specific characteristics for respirable crystalline silica.
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