Radiation occurs from two sources.
Natural radiation exists due to materials present in the earth and
particles arriving from outer space.
Artificial radiation is caused by man-made processes.
However, there is no difference in the effects of the radiation
regarding its source.
An average person in the UK will receive approximately 10% of their
annual dose of radiation from the sun's cosmic rays whilst a
further 50% is due to radon (Rn) - a gas generated from
naturally-occurring uranium present in the earth.
Artificial radiation sources included medical treatments
(approximately 15%) and fallout from nuclear tests and accidents
(approximately 1%).
A person will be continually exposed to a low level of radiation
throughout their life - this is perfectly normal and does not cause
any health effects.
Exposure to large amounts of radiation however can cause sterility,
cataracts or even death.
Lower amounts of exposure over a long period of time can cause
cancer or hereditary defects in descendants.
Radon exposure is thought to cause about 2,500 deaths per year in
the UK.
