Due to its complex topology and geology, Switzerland shows high spatial variations in exposure to background radiation. In a previous study on background radiation and childhood cancer risks in Switzerland we used previously published exposure models to estimate children’s radiation exposure (read more about that study here).
In the CALIRIS project, we developed a new geographic exposure model for natural background radiation. For this, we have mapped terrestrial radiation using modern statistical methods and about 40’000 radiation measurements. The map and how we computed it are published here.
In addition, the new exposure model now also has a time-trend for the exposure to radiation from Caesium-137. Caesium originates from the Chernobyl accident in 1986 due to which large parts of Europe were contaminated. Over time, the amount of radiation exposure due to the contamination decreased because of the radioactive decay, but also because the Caesium atoms are transported deeper into the ground and washed away.
The third included exposure source is cosmic radiation, for which exposure depends mainly on altitude.
The improved exposure model will be used for a new study on background radiation and childhood cancer risk using a much larger sample size than the previous study.