Size distributions of occupational airborne asbestos textile fibres as determined by transmission electron microscopy

Our plain-English summary of Size distributions of occupational airborne asbestos textile fibres as determined by transmission electron microscopy, by A.P. Rood, R.R. Streeter (The Annals of Occupational Hygiene, 1984).

The study

• Authors: A.P. Rood, R.R. Streeter
• Journal: The Annals of Occupational Hygiene
• Published: 1984;28(3):333-9
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The size distributions of airborne chrysotile fibres, associated with the processes of carding, spinning and weaving in an asbestos textile factory, have been evaluated by transmission electron microscopy. The distributions were approximately log-normal, with little change between processes. Median lengths and diameters were 1.6 and 0.08 µm, respectively. The results indicate that about 60% of fibres would not be seen by scanning electron microscopy, under the usual conditions, and an even larger proportion would be missed by optical microscopy. For fibres longer than 5 µm, then, about 70% of fibres would be seen by the scanning electron microscope. An optical microscope with a resolution of 0.5 µm would see approximately one quarter of all fibres greater than this length.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study measured the sizes of airborne chrysotile asbestos fibres in an asbestos textile factory using transmission electron microscopy. Fourteen air samples were taken near machines used for carding (five samples, 519 fibres measured), spinning (four samples, 424 fibres) and weaving (five samples, 495 fibres). Fibre sizes differed little between samples or between processes. Overall, the median fibre length was 1.6 micrometres and the median diameter was 0.08 micrometres. About 60% of all fibres were thinner than 0.1 micrometres, the detection limit of the usual scanning electron microscopy method, and 93% were thinner than 0.3 micrometres, the limit the authors used for optical microscopy. About 11% of fibres were longer than 5 micrometres. Among these longer fibres, about 26% were below the detection limit of the usual scanning electron microscopy technique and 75% were below the detection limit of the phase-contrast optical microscope. The authors suggested that airborne fibre sizes may depend on characteristics of the fibre itself, such as grade and origin, rather than on the processing equipment.

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: Industrial hygiene measurement study: transmission electron microscopy of static air samples to describe airborne fibre size distributions
• Who was studied: Fourteen static air samples from one asbestos textile factory (location and sampling dates not stated): four from spinning (424 respirable fibres measured), five from carding (519 fibres) and five from weaving (495 fibres)
• Exposure: Airborne chrysotile fibres sampled within about 2 m of machines and extraction systems for carding, spinning and weaving. Non-chrysotile fibres were excluded.
• Main results:
  • Fibre size distributions were approximately log-normal, with little variation between processes.
  • Overall, the median length was 1.6 micrometres (geometric standard deviation 2.4) and the median diameter was 0.08 micrometres (2.3).
  • The geometric mean diameter was 0.09 micrometres for carding and 0.08 micrometres for spinning and weaving.
  • The geometric mean length was 1.5 micrometres for carding and 1.7 micrometres for spinning and weaving.
  • Of all fibres, about 60% had diameters under 0.1 micrometres (the SEM detection limit) and 93% were under 0.3 micrometres (the optical limit).
  • About 11% of fibres were longer than 5 micrometres. Of these longer fibres, about 74% had diameters over 0.1 micrometres and 25% had diameters over 0.3 micrometres.
  • For fibres longer than 5 micrometres, about 26% were below the detection limit of the usual SEM technique and 75% were below the detection limit of the phase-contrast optical microscope (PCOM).
  • The authors suggested that airborne size distributions may depend on fibre characteristics such as grade and origin rather than on the processing equipment.
• The authors' conclusion: The authors concluded that about 60% of all fibres were below the detection limit of the usual SEM method and about 93% were below the detection limit of the phase-contrast optical microscope.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Chrysotile.

Medical terms in this study, explained in our Lexicon: Transmission Electron Microscopy (TEM), Chrysotile, Carding, Scanning Electron Microscopy (SEM).

Related studies

• A comparison of light microscopy and transmission electron microscopy results in the evaluation of the occupational exposure to airborne chrysotile fibres — A. Marconi, E. Menichini, et al. (1984)
• 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)
• Airborne fiber size characterization in exposure estimation: Evaluation of a modified transmission electron microcopy protocol for asbestos and potential use for carbon nanotubes and nanofibers — J.M. Dement, E.D. Kuempel, et al. (2015)
• A study of the size distributions of airborne amosite fibres in the manufacture of asbestos insulation boards — S.T. Beckett, J.L. Jarvis (1979)
• Indoor asbestos levels on a housing estate (determined by transmission electron microscopy) — D. Gazzi, G.W. Crockford (1987)
• Estimates of historical exposures by phase contrast and transmission electron microscopy in North Carolina USA asbestos textile plants — J.M. Dement, D. Myers, et al. (2009)

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