Background Radiation

Background radiation is the ubiquitous ionizing radiation that the general population is exposed to, including natural and artificial sources.

Both natural and human-made background radiation varies by location.

Average annual human exposure to ionizing radiation (millisievert)
Radiation source World Range USA Japan Remark
Inhalation of air 1.26 0.2-10.0 2.28 0.40
Ingestion of food & water 0.29 0.2-1.0 0.28 0.40
Terrestrial radiation from ground 0.48 0.3-1.0 0.21 0.40
Cosmic radiation from space 0.39 0.3-1.0 0.33 0.30
sub total (natural) 2.40 1.0-13.0 3.10 1.50
Medical 0.60 3.00 2.30
Consumer items - 0.13
Atmospheric nuclear testing 0.005 - 0.01
Occupational exposure 0.005 0.005 0.01
Chernobyl accident 0.002 - 0.01
Nuclear fuel cycle 0.0002 0.001
Other - 0.003
sub total (man-made) 0.6 0 to tens 3.14 2.33
Total 3.00 0 to tens 6.2 3.83 millisievert

The natural background radiation of the human environment is a combination of:

  • Sources in water and food that are incorporated into the body;
  • Airborne radon gas released from the decay of uranium and thorium in the Earth's crust;
  • Direct irradiation from radioactive materials in the ground;
  • Direct sources from outer space, such as cosmic rays;
  • Secondary radiation, produced by the bombardment of the atmosphere by cosmic rays.

Natural sources of background radiation account for most human exposure to ionizing radiation. Most artificial exposure is due to radiological imaging and radiation therapy. Other artificial sources of background radiation such as:

  • building materials, cigarettes, and other products that incorporate radioactive sources from nature;
  • Self-luminous dials and signs
  • Global radioactive contamination consequent to nuclear weapons testing
  • Nuclear power station and nuclear fuel reprocessing accidents
  • Normal operation of nuclear power facilities and like scientific research
  • Emissions from burning fossil fuels, such as those of coal-fueled power plants

Read more about Background Radiation:  Natural Background Radiation, Human-caused Background Radiation, Other Usage

Famous quotes containing the words background and/or radiation:

    “... every experience in life enriches one’s background and should teach valuable lessons.”
    —Mary Barnett Gilson (1877–?)

    “There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
    —Camille Paglia (b. 1947)