The effect of non-asbestos fibres and sample fibre density on the agreement between laboratories evaluating membrane filter samples of airborne asbestos dust

摘要: Abstract During an exchange of mounted membrane filter samples between six British laboratories, some the participants counted as asbestos all fibres which fitted a geometric definition, whilst others evaluated only those subjectively considered to be asbestos. This was found result in different counting levels depending both upon type sample and method used identify fibres. Once criteria had been agreed, however, no significant difference level detected three laboratories. The also highlighted difficulty obtaining good agreement laboratories when have fibre density on less than 20 mm−2.