Radioactivity: always and everywhere

> What is radioactivity and ionising radiation?
> Cosmic radiation
> Natural radioactive substances
> Medical exposure


Radioactivity and ionising radiation are natural phenomena always present in the natural environment. In our daily lives we are confronted with various significant radiation sources: cosmic radiation, natural radioactive substances and medical applications of ionising radiation. The millisievert is the unit that quantifies the level of potential radiation damage to the human body, also referred to as the dose.
  • In Belgium the average exposure to ionising radiation is 4.6 millisievert per annum.
  • 2.5 millisievert comes from natural sources: the natural background radiation.
  • Medical applications account for 2.1 millisievert.
  • The limit for an employee in the Belgian nuclear sector is set at 20 millisievert per twelve consecutive months.