Rate of decline of asbestos fibre concentrations in room air

Our plain-English summary of Rate of decline of asbestos fibre concentrations in room air, by J. Prentice (The Annals of Occupational Hygiene, 1985).

The study

• Author: J. Prentice
• Journal: The Annals of Occupational Hygiene
• Published: 1985;29(3):439-40
• Type of article: Letter
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004118).

In plain English

This was a letter to the editor, not a research study. The author, of McCrone Research Associates Ltd (MRA Ltd), London, commented on a 1984 report by Moorcroft and Duggan about airborne asbestos fibres after asbestos removal is complete, a check called clearance sampling. The author reported that the firm first observed a rapid decline of airborne fibre concentrations in rooms in the late 1970s and had seen it consistently in its clearance work since. The firm therefore advocated manually disturbing all potential dust sources during clearance sampling and sampling for about one hour. The author wrote that 80-minute samples at 3 litres per minute were the most sensible compromise between sensitivity and the fatigue of the person disturbing the dust. When the firm was asked for four-hour samples at 2 litres per minute, extra shorter, lower-volume samples gave consistently higher calculated results, while the total number of fibres counted was about equal. The letter gave no fibre counts, concentrations or numbers of samples. The author concluded that clearance measurement requires some sacrifice of sensitivity and precision to gain realistic assurance that future workers' exposure is reduced to the lowest level practicable.

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: Letter to the editor commenting on a published short communication, based on the author's firm's practical experience with clearance sampling
• Who was studied: Rooms where clearance sampling was done after asbestos removal, in the work of MRA Ltd (London) from the late 1970s onward; no number of sites or samples given
• Exposure: Airborne respirable asbestos fibre in room air after asbestos removal (fibre type not specified); comparison of sampling durations and volumes
• Main results:
  • MRA Ltd observed a rapid decline of airborne fibre concentrations in rooms, first in the late 1970s
  • The firm advocated manual disturbance of all potential dust hosts during clearance sampling and sampling times of about one hour
  • In the firm's practice, samples taken for 80 minutes at 3 litres per minute were the most sensible compromise
  • When four-hour clearance samples at 2 litres per minute were requested, extra shorter, lower-volume samples gave consistently higher calculated results
  • The total number of fibres counted on long and short samples was about equal, and no excess of fibres was counted on longer samples when no additional disturbance was performed
• The authors' conclusion: The author concluded that measuring asbestos fibres in clearance situations requires some sacrifice of sensitivity and precision in order to gain realistic assurance that future workers' exposure is reduced to the lowest level practicable

Related studies

• Rate of decline of asbestos fibre concentration in room air — J.S. Moorcroft, M.J. Duggan (1984)
• Environmental measurements of total dust and fiber concentration in manufacturer and user of man-made mineral fibers — J.H. Kim, H.S. Chang, et al. (1999)
• Development of a fibre size-specific job-exposure matrix for airborne asbestos fibres — J.M. Dement, E.D. Kuempel, et al. (2008)
• A comparison of parallel dust and fibre measurements of airborne chrysotile asbestos in a large mine and processing factories in the Russian Federation — E. Feletto, S.J. Schonfeld, et al. (2017)
• A study of personal and area airborne asbestos concentrations during asbestos abatement: a statistical evaluation of fibre concentration data — J.H. Lange, P.R. Lange, et al. (1996)
• The use of a new static device based on the collection of the thoracic fraction for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy — E. Kauffer, J.C. Vigneron, et al. (1996)

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