Radiation
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. There is no difference in the effects of the radiation regarding it's source.
Introduction
An average person in the UK will receive approximately 10% of their annual dose of radiation from the suns cosmic rays, whilst another 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 fall out 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.