You've grown up on a planet which has, in places, quite a high level of background radiation, and life on Earth has evolved to cope with this. Your cells have self-repairing mechanisms which allow them to survive relatively unscathed.

The amount of background radiation varies considerably around Britain, as shown on the map. You can see that it is particularly high in Cornwall, because of the types of rock there.

Find out about the units we use to measure radioactivity:

Background radioactivity is mainly natural radioactivity, all around us. As you can see from the pie chart, the vast majority of our annual dose comes from radon gas, food & drink, the ground, and cosmic rays (which are gamma rays coming in from space).

Unless you are having radiotherapy, your dose from medical sources is quite low. The chart also shows that the nuclear industry adds very little to the level of background radioactivity.

Many people don't realise that your radiation dose from cosmic rays is increased considerably if you fly a great deal. This is because our atmosphere provides some protection against cosmic rays, so the higher you fly the more you get.

However, don't worry - this only tends to be a problem if you're an airline pilot or an astronaut.