Man-Made Sources

Man made sources of ionizing radiation account for about 18% of your total radiation exposure. At first glance that may seem like a lot, but in reality, most of that exposure comes from medical imaging and treatments. So, depending on how many medical treatments you have had in the past year, your exposure to man made ionizing radiation could be much lower.

Man-Made Sources of Ionizing Radiation
Source
Percentage of Total
Medical x-rays
61.1%
Nuclear medicine treatments
22.2%
Consumer products
16.7%
Other
<1%

Consumer products such as smoke detectors, for example, use the radioactive isotope americium-241. Atmospheric fallout from above-ground nuclear weapons tests carried out between 1945 and 1980 and the Chernobyl nuclear accident are other sources of man made ionizing radiation.

Nuclear power plants are also a source of ionizing radiation. Nuclear reactors and used fuel are heavily shielded from the environment so your exposure to ionizing radiation from nuclear power plants is almost zero.

Emissions from the burning of fossil fuels are a source of ionizing radiation because tiny amounts of uranium and other radioactive isotopes are present in crude oil and coal. When fossil fuels are burned, some of these isotopes are present in the ash and released into the atmosphere to go wherever the wind takes them.

Man-made sources of ionizing radiation from consumer products, power plants, manufacturing processes, food irradiation and fallout account for a little over 1% of your total radiation exposure.

Sources of Ionizing Radiation
Source
Percentage of Total
Radon
55%
Medical x-rays
11%
Internal
11%
Cosmic
8%
Terrestrial
8%
Nuclear medicine treatments
4%
Consumer products
3%
Other (occupational, fallout, nuclear fuel cycle)
<1%

Source:

Natural Resources Canada, www.nrc.gov/reading-rm/basic-ref/teachers/06.pdf.