Document peXMZjEZ0rxON6vGRDjarr636

Prellminaiy Duet Surrey for Asbestos Textile Institute, June, I9U7 23. employed conventional dust count techniques vhlch, In effect, related Incidence of asbestosis to the number of non-flbrous particles of a size ranging from ans / to fire or 10 microns. For Illustration, suppose the causatire dust element is scansthing different, e.g., fibers that are less than 50-60 microns long, end less than 1-2 microns in diameter. conventional dust count method uould be satis factory only' If there vere a fairly constant ratio between the two -types of dost; it would, in that case, provide an adequate, index. Preliminary Studies on Qualities of Asbestos Dust With a view to eventual development of supplementary methods for measuring asbestos dust concentretiqna cn a weight basis, ve have conducted seme preliminary studies directed to the colorimetric determination of total silica in tbs minute quantities of asbestos dust obtained In a typical atmos pheric sample. This requires development since it could provide a valuable tool for further Investigation. Sub-mlcroaooplo particles aid fibers. Another aspect of the dust examination problem an which preliminary -work has been dons Involved studies with the eleotron microscope. Vs posed, the two following questions: 1. Ordinary dust particles, cos to three microns in diameter, com prise moot of the particles in the dust count. They lode like ordinary in dustrial dust and ve refer to them aa "cubical" as distinguished from "fibrous" particles. The question, is: are these particles in fact nan-fibrous or are they bundles of fibers?