3. Measuring radon emissions

Radon gas emanations can be measured using "spot or instantaneous measurements". These involve exposing the dosimeter for a few minutes, then immediately measuring by counting.

This type of analysis is not very meaningful, as it is extremely variable depending on the period of gas activity.

Continuous measurements" produce sampling. They enable simultaneous (or slightly delayed) analysis of temporal variations in volumetric activity over a maximum period of one hour. Integrated" measurements enable the temporal integration of physical quantities linked to the decay of radon or its progeny (number of traces, number of charges, number of atoms).

Given the possible, and possibly significant, variations in radon activity inside homes, only this type of determination can be used to assess health risk.

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