in the UK there are many areas that Radon can be an issue from: https://www.ukradon.org/information/ukmaps https://www.ukradon.org/information/ukmaps "Every b

in the UK there are many areas that Radon can be an issue from: https://www.ukradon.org/information/ukmaps https://www.ukradon.org/information/ukmaps "Every building contains radon but the levels are usually low. The chances of a higher level depend on the type of ground. Public Health England has published a map showing where high levels are more likely." getting a sensor at a reasonable price is tricky since Radon emits Alpha radiation - I managed to get one at around £300