Monitoring and evaluating man – made mineral fibres: work of a WHO/EURO reference scheme.

In the mid-1970s, a meeting held at WHO in Copenhagen launched a research programme on the health effects of man-made mineral fibres. As part of this programme, a WHO/EURO Reference Scheme was initiated in 1980 to improve comparability of data obtained from epidemiological studies and thus reduce the level of uncertainty in the risk assessment process. The scheme involved developing reference methods for evaluating airborne MMMF concentrations and size distributions by phase contrast optical microscopy (PCOM) and scanning electron microscopy (SEM). These methods were tested in a series of inter-laboratory counting trials. Interim progress in the scheme was published in 1985. This paper updates the work of the scheme and confirms that the previously published improvements in reproducibility of measurement have been maintained.