Sources of Ionizing Radiation
From Thermal-FluidsPedia
Ionizing radiation can come from both natural and man-made sources. Natural (background) sources of radiation are cosmic radiation and terrestrial radiation. Cosmic radiation is due to interactions between earth’s magnetic field and charged particles coming from the sun and other distant stars. Cosmic radiation is stronger at higher elevations. Sources of terrestrial radiation are uranium and products of its decay such as thorium, radium, and radon, which are found in soil. Our body also contains radioactive materials such as potassium-40, carbon-14, and lead-210 when we are born.
Man-made (anthropogenic) sources of radiation come from nuclear reactors, consumer products, irradiated food, medical checkups, and radiation therapy. Precluded from this list is possible exposure due to the accidental release of nuclear radiation from nuclear reactors, testing of nuclear bombs, or nuclear wars. It is therefore reasonable to assume that the geographical location we live in, our lifestyle, and the state of our health all affect the amount of radiation to which we are exposed. Because the earth itself contains radioactive materials, the food and water we consume may also be affected. Even the materials from which our houses are made contribute. For example, stone and bricks are more radioactive than wood and aluminum. Consumer products such as televisions and computer screens, luminous watches and dials, smoke detectors, and airport x-ray machines (See box “X-ray Vision”) also contribute to the radiation doses we regularly receive.
In addition to the sources mentioned above, there are other sources such as alpha particles, beta particles, and neutrons which may occur naturally in the outer atmosphere or may be produced in nuclear fission processes.
References
(1) Toossi Reza, "Energy and the Environment:Sources, technologies, and impacts", Verve Publishers, 2005