The Industrial Environment: Its Evaluation and Control (Syllabus) (1965)

The supplied text is not the cited DallaValle book. It is section B-6, "Dust Counting Techniques", by Robert L. Harris, Jr., from a U.S. Public Health Service syllabus revised in 1965. It is a methods chapter, not a health study, and does not mention asbestos. It explains how to count mineral dust particles collected in impinger samplers, including the 1942 standard method, settling times and counting statistics. In one project, some 100 samples were counted in the field within 24 hours and again about 1 to 2 weeks later. Only 25% of pairs fell within the 50% limits and 55% within the 90% limits; 65% gave lower laboratory counts. At 90F and 85 percent relative humidity, a sampling liquid that began as commercial 95.5 percent ethyl alcohol fell to about 60 percent alcohol after 20 minutes of sampling. The author suggested settling times giving counts matching quartz settling in water for 30 minutes. Noting that observers differ in seeing small particles, the author wrote that it appears differences between counters cannot be eliminated except by selecting counting personnel.

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From J-M's medical library

This copy comes from the Johns-Manville medical library. J-M listed it in its medical library index as no. 005288. Barry Castleman cites it in chapter 10, "Historical Research on Toxic Substances", of Asbestos: Medical and Legal Aspects (5th ed., 2005); see Reading Castleman.