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

Our plain-English summary of 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, by E. Kauffer, J.C. Vigneron, Fabriès, et al (The Annals of Occupational Hygiene, 1996).

The study

• Authors: E. Kauffer, J.C. Vigneron, Fabriès, M.A. Billon-Galland, P. Brochard
• Journal: The Annals of Occupational Hygiene
• Published: 1996;40(3):311-9
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A new static device, the CATHIA sampling head, based on the collection of the thoracic fraction is proposed for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy. By comparison with a standard aerosol sampling head, it has been shown that this sampler reduces the total mass concentration, but does not introduce any change in the most common index used to characterize an asbestos aerosol fibre, that is the concentration of fibres with length greater than 5 microns, diameter less than 3 microns and length to diameter ratio greater than 3. The homogeneity of the deposited dust on the collection filter favours the use of this sampling head with both the indirect and direct preparation methods.

In plain English

This French study tested a new stationary air sampler called CATHIA. It collects the 'thoracic fraction' of dust (particles that can enter the airways) for counting asbestos fibres by transmission electron microscopy. The authors compared it with a standard head that does not select particles by size and is routinely used in France for asbestos in non-occupational environments. They collected 11 pairs of filters with both heads in an asbestos paper factory and 13 pairs in asbestos contaminated buildings. Counted fibres were longer than 5 micrometres, thinner than 3 micrometres, and over three times longer than wide. In both settings, dust mass concentrations differed significantly between heads, while fibre number concentrations did not. The standard head's average dust mass concentrations were 78% higher in the factory and 51% higher in the buildings. Dolomite dust tests showed an even filter deposit with CATHIA but not with the standard head. The authors concluded that CATHIA reduces total mass concentration without changing the usual fibre index, and allows both direct and indirect sample preparation. They noted this may not hold for coarser fibres such as man-made mineral fibres.

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 comparison study: paired air sampling with a new thoracic-fraction sampling head (CATHIA) and a standard non-selective sampling head, plus chamber tests of how evenly dust is deposited on the filters
• Who was studied: Air samples, not people: 11 pairs of filters from a factory manufacturing asbestos paper and 13 pairs from asbestos contaminated buildings (France), plus eight dolomite dust sampling runs in an experimental chamber
• Exposure: Airborne asbestos fibres in an asbestos paper factory and in asbestos contaminated buildings (fibre type not specified). The fibres counted were those longer than 5 micrometres, with diameter less than 3 micrometres and aspect ratio greater than 3.
• Main results:
  • In the dolomite chamber tests, the three parts of filters from the CATHIA head showed no differences (P greater than 0.9), while filters from the standard head showed strong inhomogeneity (P less than 0.01)
  • For the 11 paired factory samples, mass concentrations differed significantly between the two heads (P less than 0.01), while fibre number concentrations did not differ significantly
  • For the 13 paired samples from asbestos contaminated buildings, the Wilcoxon test led to the same conclusion as for the factory: mass concentrations differed significantly and fibre number concentrations did not. This held (P greater than 0.4) under an alternative treatment of samples where no fibres were detected.
  • Gravimetric (mass) concentrations with the standard head were on average 78% higher than with CATHIA for factory samples, and 51% higher for samples from asbestos contaminated buildings
• The authors' conclusion: The authors concluded that the CATHIA head gives a homogeneous filter deposit, so both direct and indirect preparation methods can be used. They also concluded that it reduces total mass concentration without changing the most common asbestos fibre index. With the standard head, the direct preparation method cannot be used.
• Limitations the authors state:
  • The authors noted that similar fibre counts were expected for thin fibres like most asbestos, and that this could not be the case for coarser fibres such as man-made mineral fibres
  • In the buildings, concentrations were low and the chance of detecting no fibres on the examined grid area was high, so many results were below the analytical sensitivity

Topics

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

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

Related studies

• Size distributions of occupational airborne asbestos textile fibres as determined by transmission electron microscopy — A.P. Rood, R.R. Streeter (1984)
• 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)
• A technical comparison of evaluating asbestos concentration by phase-contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report — R.F. Dodson, S.P. Hammar, et al. (2008)
• Performance of asbestos fibre counting laboratories by transmission electron microscopy — B. Préat (2001)
• Personal and static sample measurements of asbestos fibres during two abatement projects — A. Dufresne, C. Dion, et al. (2009)
• 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)

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