Indoor 222Rn concentration in the exhibition and storage rooms of Polish geological museums

The radon exhaled from radioactive mineral collections exhibited in five Polish geological museums may influence its total indoor concentration. Radon concentrations measured in the exhibition halls do not pose a risk for visitors or museum staff. However, air exceeding the ICRP (2007) action limit for workers (equal to 300 Bq/m3) was noted in the storage rooms of two museums. Significant222Rn activity concentrations equal to more than ~300 kBq/m3were measured inside lead containers where radioactive minerals were stored.