Ann. occup. Hyg., Vol. 46, No. suppl_1, pp. 125-127, 2002
© 2002 British Occupational Hygiene Society
Published by Oxford University Press
Airborne Asbestos Fibres in Steam Tunnels: A Qualitative Analysis by PLM and a Quantitative Analysis by PCOM and TEM/EDS
Department of Epidemiology, Biostatistics and Occupational Health, McGill University 3450 University Street, Montreal, Quebec, Canada H3A 2A7
*Author to whom correspondence should be addressed. E-mail: andre.dufresne{at}mcgill.ca
A question often asked of industrial hygienists is whether or not asbestos fibres can be propagated by air draughts on altered insulating material. An occupational hygiene survey was conducted during the summer of 1999 throughout the steam tunnels of a university campus to determine airborne concentrations of asbestos fibres in order to answer this question. Results were compared with the so-called clearance test standard (0.01 f/ml used in the Province of Québec) for work liable to produce asbestos dust emission. Some 3.2% of the results were over the clearance test standard when airborne concentrations of asbestos fibres were determined by phase contrast optical microscopy. However, 41.9% of the results were over the clearance test standard when ambient samples were counted by transmission electron microscopy/energy dispersive spectroscopy (TEM/EDS) for asbestos fibres only and reached 48.4% for all TEM mineral fibres. Of the TEM/EDS results, 3.2% were >0.1 f/ml, the threshold limit value proposed by ACGIH.
asbestos TEM analysis PCOM analysis steam tunnel