Activity concentration

Rate of activity of a radionuclide to the volume of the material in which the radionuclide is distributed.

The activity concentration of the air is given in the unit Becquerel per cubic metre (Bq/m³). The activity concentration of the air states which activity of a certain radionuclide is included in one cubic metre air.

The activity concentration of liquids is given in the unit Becquerel per liter (Bq/l). The activity concentration in liquids indicates how much activity of a particular radionuclide is contained in one liter of a liquid.