Producing samples for the organization of proficiency tests. Study of the homogeneity of replicas produced from two atmosphere generation systems

Our plain-English summary of Producing samples for the organization of proficiency tests. Study of the homogeneity of replicas produced from two atmosphere generation systems, by L. Freville, J.C. Moulut, M. Grzebyk, et al (The Annals of Occupational Hygiene, 2010).

The study

• Authors: L. Freville, J.C. Moulut, M. Grzebyk, E. Kauffer
• Journal: The Annals of Occupational Hygiene
• Published: 2010;54(6):659-70
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This article describes two atmosphere generation systems used for the production of replicas. The first, the Sputnic system, is based on the Sputnic air sampler developed by the National Institute of Occupational Health in Oslo (Norway). It is used to generate asbestos fibres or silica particles and allows the simultaneous production, by means of sampling on filters, of up to 114 replicas. The second is a multipurpose system that allows dust sampling on foams used with the CIP 10-R device. Twenty samples can be taken simultaneously. In total, 120 series of samples allowed characterization of the variability of the two generation systems used for the production of replicas loaded with asbestos fibres or silica dust. The coefficients of variation characterizing the dispersion of the filter loading in the Sputnic system are <10% for high densities asbestos fibre or silica dust samples. The coefficient of dispersion is on average higher when the asbestos fibre density is lower. The differences observed between the measurements taken on the different crowns of the Sputnic system are low and <2%. The results obtained with the multipurpose system show that replica dispersion is on average equal to 4%, which will allow proposal in the near future of a proficiency test dedicated to the quantitative analysis of crystalline silica on foams sampled with the CIP 10-R device.

In plain English

This was a laboratory study of sampling equipment, not a study of people or disease. INRS researchers in France tested how evenly two machines spread airborne dust onto matching samples ("replicas"). The first, the Sputnic system, makes replicas for INRS asbestos-counting and silica proficiency tests. It loaded filters with chrysotile asbestos fibres or silica (quartz). A second, "multipurpose" system loaded CIP 10-R sampler foams with a quartz and talc mixture. In all, 120 sampling series were analysed. On the Sputnic system, the mean coefficients of variation for the different sample categories ranged from 6.3 to 17.5%. For silica and higher-density asbestos samples these means were 6.3 to 8.2%. Variation was higher at lower asbestos fibre densities, although the 17.5% figure rested on a single determination. Each measurement was scaled to its experiment's average and results were pooled across experiments. On that basis, each ring ("crown") of sampling points was within 2% of the average, excluding Crown 6, which had limited results. The multipurpose system averaged 4%. The authors concluded this would allow them to propose a future proficiency test for silica on CIP 10-R foams.

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: Laboratory validation of two atmosphere generation (dust-sampling) systems used to produce replica samples for proficiency tests
• Who was studied: No people were studied. The study analysed 120 sampling series at INRS, France. On the Sputnic system these were 40 silica series and asbestos series on filters (38 on 25 mm filters and 31 on 37 mm filters). On the multipurpose system there were 11 silica series of 20 CIP 10-R samplers each.
• Exposure: Generated aerosols of chrysotile asbestos fibres and of silica (alpha-quartz) on the Sputnic system, and mixtures of alpha-quartz and talc on foams in the multipurpose system
• Main results:
  • Sputnic system: the mean coefficients of variation for the different sample categories in Table 1 ranged from 6.3 to 17.5%
  • Sputnic system: for silica samples and for asbestos samples with fibre density above 63.7 fibres per square millimetre, the mean coefficients of variation were between 6.3 and 8.2%
  • Sputnic system: at asbestos fibre densities below 63.7 fibres per square millimetre, mean coefficients of variation were 11.7% on 25 mm cassettes and 17.5% on 37 mm cassettes. The 37 mm figure came from only one determination.
  • Sputnic system: for asbestos fibre samples, mean results did not differ between crowns (P = 0.12 for 25 mm cassettes, P = 0.26 for 37 mm cassettes)
  • Sputnic system: for silica samples, means differed statistically between crowns. Each measurement was divided by its experiment's mean, and the crown means were pooled across all experiments. Excluding Crown 6, which had limited results, these pooled crown means diverged from unity by at most 2%, with no gradient.
  • Multipurpose system: mean replica dispersion (coefficient of variation) for quartz on foams was 4% across 11 series. For the whole quartz and talc mixture it was 1.8%.
• The authors' conclusion: The authors concluded that the multipurpose system's average replica dispersion of 4% will allow them to propose, in the near future, a proficiency test for the quantitative analysis of crystalline silica on foams sampled with the CIP 10-R device.
• Limitations the authors state:
  • The low-density asbestos result for 37 mm cassettes rested on only one determination
  • Only limited results were available for Crown 6, and no samples could be taken on Crown 5 with 37 mm cassettes
  • Comparing results with other authors' systems is difficult because the sampling systems, replica numbers, experiment numbers and dust types differ

Topics

Medical terms in this study, explained in our Lexicon: Crystalline.

Related studies

• A comparison of fibre counting across three European national proficiency testing schemes — A.D. Jones, M.C. Arroyo, et al. (2005)
• Continued participation in an asbestos fiber-counting proficiency test with relocatable grid slides — M. Harper, J.E. Slaven, et al. (2009)
• Proposal to adapt the WASP programme to fibre counting tests — M. Grzebyk, E. Kauffer, et al. (2006)
• Personal and static sample measurements of asbestos fibres during two abatement projects — A. Dufresne, C. Dion, et al. (2009)
• Study of the count-to-mass conversion factor for asbestos fibres in samples collected at the emissions of three industrial plants — S. Puledda, A. Marconi (1991)
• Development of rapid and highly accurate method to measure concentration of fibers in atmosphere using artificial intelligence and scanning electron microscopy — Y. Iida, K. Watanabe, et al. (2021)

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