The biggest source of radiation in normal life is from radon gas in the ground. This is a natural thing, but if it comes up from the ground and gets trapped in a building can cause radiation exposure. About 50% of the average dose in the UK comes from radon gas. It is possible to monitor a building to see if it is a problem, and to put measures in place to help reduce the level of radon gas if it is a problem though.
Comments
Colin commented on :
To add to this visit the following link
https://www.gov.uk/government/publications/ionising-radiation-dose-comparisons/ionising-radiation-dose-comparisons
I