Personal and static sample measurements of asbestos fibres during two abatement projects

Our plain-English summary of Personal and static sample measurements of asbestos fibres during two abatement projects, by A. Dufresne, C. Dion, A. Frielaender, et al (Bulletin of Environmental Contamination and Toxicology, 2009).

The study

• Authors: A. Dufresne, C. Dion, A. Frielaender, E. Audet, G. Perrault
• Journal: Bulletin of Environmental Contamination and Toxicology
• Published: 2009;82(4):440-3
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Exposure assessment was performed during the abatement of amosite containing material (ACM) and chrysotile containing material (CCM). Mean fibre concentrations (MFC) in breathing zone (BZ) were 20.6+/-7.9 f/cc and 6.3+/-2.2 f/cc during abatements of ACM and CCM, respectively. At the fixed station, MFC were 5.4+/-3.5 f/cc for ACM and 2.9 f/cc+/-1.6 for CCM. For observer's BZ, MFC were 3.1+/-1.3 f/cc (ACM) and 1.8 f/cc (CCM) during the abatement. Though elevated, area and observer-type samples clearly underestimate exposure. Exposure remained unacceptable in the worksite with the class of respiratory protection used.

In plain English

This field study measured airborne asbestos fibres during two abatement projects. One removed friable material containing 75%–90% amosite. The other removed ceiling fireproofing and insulation containing 5%–10% chrysotile in gypsum and mica. The authors compared samples from workers' breathing zones with samples from fixed stations near the work and from an observer, one of the authors, who stayed away from the removal platform. During amosite removal, workers' samples averaged 20.3 f/cc (8 samples), against 5.4 f/cc at the fixed station and 3.1 f/cc for the observer. During chrysotile removal, the averages were 6.3 f/cc (18 samples), 2.9 f/cc and 1.8 f/cc. Workers' levels were 2.2 to 3.8 times the fixed-station levels and 3.5 to 6.5 times the observer's levels. Workers wore powered HEPA respirators with a NIOSH assigned protection factor of 50. The authors said this protection allowed up to 10 f/cc for amosite under Québec limits. The authors concluded that area and observer samples underestimated worker exposure. They also concluded that exposure at the amosite site remained unacceptable with the respiratory protection used.

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: Workplace exposure-measurement study comparing simultaneous personal breathing-zone, observer and fixed-station (area) air samples during two asbestos abatement projects
• Who was studied: Workers on two asbestos abatement projects: 2 workers (8 samples) during amosite removal and 3 workers (18 samples) during chrysotile removal. Also sampled: one observer (a non-worker who was one of the authors), fixed stations near the removal work, and 5 samples by a hired consultant during the amosite project. The article cites Québec regulations but does not give the dates or exact location of the worksites.
• Exposure: Removal of friable material containing 75%–90% amosite (ACM), and of material containing 5%–10% chrysotile in a gypsum and mica matrix used for fireproofing and insulation at ceiling level (CCM). Tasks included scraping insulation, sweeping surfaces, moving scaffolds and moving bags. Workers wore powered HEPA respirators (NIOSH assigned protection factor 50), and water mist was sprayed.
• Main results:
  • Workers' breathing zone: mean 20.3 f/cc (n = 8; SD = 7.9) during amosite abatement and 6.3 f/cc (n = 18; SD = 2.2) during chrysotile abatement
  • Fixed station: mean 5.4 f/cc (n = 5; SD = 3.5) for the amosite project and 2.9 f/cc (n = 6; SD = 1.6) for the chrysotile project
  • Observer's breathing zone: mean 3.1 f/cc (n = 2; SD = 1.3) during amosite abatement and 1.8 f/cc (n = 3; SD = 0.33) during chrysotile abatement
  • Consultant's daily breathing-zone samples during the amosite project: mean 3.0 f/cc (n = 5; SD = 1.9)
  • Ratio of worker breathing zone to fixed station: 3.8 for amosite and 2.2 for chrysotile
  • Ratio of worker breathing zone to observer breathing zone: 6.5 for amosite and 3.5 for chrysotile
  • The Québec exposure limits cited were 0.2 f/cc for amosite and 1 f/cc for chrysotile. The authors stated that a respirator with a protection factor of 50 translates into an upper limit of 10 f/cc for amosite under the Québec limit.
• The authors' conclusion: The authors concluded that area and observer-type samples clearly underestimated workers' exposure and could allow hazardous conditions to be overlooked. They concluded that personal breathing-zone sampling was the most representative method in this case. They also concluded that workers' exposure remained unacceptable at the amosite worksite with the class of respiratory protection used.

Topics

Medical terms in this study, explained in our Lexicon: Abatement, Amosite, Chrysotile, Respirator.

Related studies

• 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)
• Exposure to airborne asbestos during abatement of ceiling material, window caulking, floor tile, and roofing material — J.H. Lange, S.L. Sites, et al. (2006)
• Asbestos abatement in a location previously improperly abated — J.H. Lange, S.L. Sites, et al. (2006)
• Personal airborne asbestos exposure levels associated with various types of abatement — J.H. Lange, K.W. Thomulka, et al. (2006)
• 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)

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