Quantitative determination of airborne respirable non-fibrous alpha-silicon carbide by x-ray powder diffractometry.
OBJECTIVE
The purpose of the present investigation was to establish a method for the determination of airborne respirable non-fibrous silicon carbide (SiC). The main application is within the industrial production of SiC.


METHODS
Due to the complex airborne aerosol mixture of crystalline compounds in the SiC industry, X-ray powder diffractometry was selected as the most appropriate method. Without any international standard material for the respirable fraction of non-fibrous SiC, pure and suitable products from three SiC plants in Norway were selected. These products have a median particle diameter in the range 4.4-5.1 mum. The method is based on thin sample technique, with the dust deposited on a polycarbonate filter. Absorption correction is done by standard procedures with the use of a silver filter, situated below the polycarbonate filter.


RESULTS
The diffraction line used for quantitative determination was selected carefully. This was done to avoid interferences from quartz, cristobalite, and graphite, which all are airborne components present in the atmosphere during the industrial process. The instrumental limit of detection for the method is 12 microg.


CONCLUSIONS
This method has been used to determine airborne non-fibrous SiC in a comprehensive ongoing project in the Norwegian SiC industry for further epidemiological studies. The method is fully applicable for compliance work.
Bye
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Department of Chemical and Biological Working Environment, National Institute of Occupational Health, PO Box 8149 Dep., N-0033 Oslo, Norway. erik.bye@stami.no
Føreland
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Lundgren
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Kruse
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K
Rønning
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D000395:Air Pollutants, Occupational / Q000032:analysis*; D017554:Carbon Compounds, Inorganic / Q000032:analysis*; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D008669:Metallurgy; D016273:Occupational Exposure / Q000032:analysis; D010316:Particle Size; D016016:Proportional Hazards Models; D017655:Silicon Compounds / Q000032:analysis*; D014961:X-Ray Diffraction
D000395:Air Pollutants, Occupational; D017554:Carbon Compounds, Inorganic; D004391:Dust; D017655:Silicon Compounds; C022088:silicon carbide