Background radiation is a measure of the amount of ionizing radiation found in the atmosphere at a given site and is not attributable to intentional radiation sources being added. Background radiation comes from a number of natural as well as artificial sources.
Both rocks and soils contain trace quantities of natural radioactivity, which can be swallowed or inhaled when disturbed at times. Radon, along with its decay products, is a gas that can collect indoors and be inhaled. We will even absorb radioactivity from the food we consume and from the drinking water.
A number of factors determine the annual dose from background radiation that everyone receives. The amount of the exposure of background radiation obtained each year from separate natural sources –
- Radon-222 (68%)
- Space (11%)
- Terrestrial (7%)
- Radon-220 (5%)
- Potassium-40 (5%)
- Thorium & Uranium Series (4%)