Dust measurement and monitoring in the asbestos industry

Our plain-English summary of Dust measurement and monitoring in the asbestos industry, by C.G. Addingley (Annals of the New York Academy of Sciences, 1965).

The study

• Author: C.G. Addingley
• Journal: Annals of the New York Academy of Sciences
• Published: 1965;132(1):298-305
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

In plain English

This paper, by an author from British Belting & Asbestos Ltd. and the Asbestosis Research Council, described methods for measuring asbestos dust in factory air. It reported tests of the Royco Particle Counter, an American light-scattering instrument. It did not study workers' health. In chrysotile workrooms, the Royco was compared with membrane filter counts and with the midget impinger. When particles over five microns were counted, the membrane count was about 25 per cent higher than the Royco count. With the Royco set at four microns and above, the Royco read about 15 per cent higher than the five-micron membrane count. At one micron and above, the relative counts were Royco 100, membrane 85 and impinger 47. Over about eight months, between 1000 and 2000 results were reported. Carding showed a higher proportion of large particles or fibers than other textile processes. The author noted that the Royco counts all dust, not only asbestos, and that it had not been tested with crocidolite or amosite. The author concluded that the instrument represented the best available method for dust testing in asbestos factories.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Methods paper: a description of dust-measuring methods and a factory evaluation comparing a light-scattering particle counter (Royco) with membrane filter and midget impinger counts
• Who was studied: No people were studied. Measurements were made of workroom air in asbestos textile processes (chrysotile workrooms) at British Belting & Asbestos Ltd., England, as part of an Asbestosis Research Council program, over about eight months (the conclusion says nine months).
• Exposure: Airborne asbestos dust in chrysotile textile workrooms, including carding and weaving, measured as particle or fiber counts in size ranges (over 1, 4 and 5 microns)
• Main results:
  • When particles over five microns were counted, the membrane filter count was about 25 per cent higher than the Royco count.
  • With the Royco set at four microns and above, compared against the five-micron membrane count, the Royco results were about 15 per cent higher.
  • Counting particles of one micron and above, the relative counts were Royco 100, membrane 85 and midget impinger 47.
  • Counting particles or fibers of five microns and upwards, the membrane filter gave a count 78 per cent higher than the midget impinger.
  • With a membrane filter placed after a midget impinger, 13 particles (one micron and above) passed through for every 87 counted on the impinger record. This was the mean of two experiments.
  • In factory use, many thousands of Royco counts were processed into between 1000 and 2000 reported results.
  • Carding showed a higher proportion of large particles or fibers than other textile processes.
  • A prototype light-scattering monitor from the University of Reading gave readings in good proportional agreement with thermal precipitator counts of particles above 5 microns.
  • Remote sampling through a two-inch bore tube with isokinetic sampling showed negligible particle loss with tubes up to at least 12 feet long.
• The authors' conclusion: The author concluded that the Royco instrument represented the best available method for dust testing in asbestos factories. The author also concluded that it allowed enough tests to give statistically reliable results without inordinate labor.
• Limitations the authors state:
  • The Royco counts all particles in the air, not only asbestos. Where other organic and mineral dusts are present, as in automobile brake lining manufacture, it records only the total dust count.
  • Any change in the asbestos used could substantially alter the ratio between Royco and membrane counts.
  • The Royco was not tested with crocidolite or amosite, and the author doubted the comparison would be valid for them.
  • Very long thin fibers would probably not register on the Royco counter.
  • The impinger pass-through result was the mean of only two experiments.
  • The instrument is physically large, so a remote sampling method is needed for some locations.
  • Counting everything from 0.3 microns upwards would be liable to cause quite large errors from normal atmospheric pollution.

Related studies

• Developments in dust sampling and counting techniques in the asbestos industry — S. Holmes (1965)
• Present threshold limit value in the U.S.A. for asbestos dust: a critique — E.L. Schall (1965)
• Economics of dust control — D.W. Hills (1965)
• Asbestos dust--a community hazard? — (1969)
• The assessment of particulate matter emitted from stone-crushing industry by correlating rock textures with particles generated after comminution and dispersed in air environment — G. Belardi, G. Vignaroli, et al. (2013)
• A comparison of impinger and membrane filter techniques for evaluating air samples in asbestos plants — H.E. Ayer, J.R. Lynch, et al. (1965)

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