4. Interpreting results

4.1 Conventional approach

The conventional approach is an old one, linked to the fact that knowledge of the distribution curve of exposure values due to environmental fluctuations is in fact not always accessible. To take account of this uncertainty, the French Ministry of Labor has proposed an evaluation grid based on the deviation of results from the TWA.

• If measurements are less than or equal to 0.3 VME, exposure is below the limit value.

• If one of the measurements is greater than 0.3 VME, exposure is above the limit value.

Note that this conventional approach is set to disappear with the new GEH probabilistic approach. If the probability of exceeding the TLV is...