[Results of an interlaboratory fibre count comparison program concerning the SEM technique].
BACKGROUND
The necessity of quality control for laboratories carrying out airborne asbestos fibre monitoring is recognized in Italian law concerning the worker and the environmental protection against asbestos. The scanning electron microscopy technique is prescribed to control the airborne fibre concentration after asbestos removal from buildings.


OBJECTIVE
In 2002 the Italian laboratories carrying out SEM analysis on asbestos were requested by the Istituto Superiore di Sanità to take part in a fibre count comparison program. Thirty-nine agreed to participate.


METHODS
Fifteen samples were exchanged among the laboratories participating in the program. Seven samples consisted of polycarbonate membranes and eight of cellulose ester membranes. The sample loads did not exceed 50 fibres/mm2. The fibre counting results were evaluated with reference to the mean value of each sample calculated from the results provided by all the participants.


RESULTS
Only 19% of the fibre count results were considered "insufficient", and the results falling within the 95% confidence interval were the 65% of the total. University and public laboratories obtained on the whole the best results.
Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanità, Roma. biagio.bruni@iss.it
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Bruni
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Martinelli
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Paoletti
D000395:Air Pollutants, Occupational / Q000032:analysis*; D001194:Asbestos / Q000032:analysis*; D007753:Laboratories / Q000592:standards*; D008855:Microscopy, Electron, Scanning; D010865:Pilot Projects; D011786:Quality Control
D000395:Air Pollutants, Occupational; D001194:Asbestos