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Facts about Nuclear Radiation

The average person receives an annual radiation dose of 360 millirems per person. 300 millirems comes from natural sources. A millirem (mrem) is a unit of absorbed radiation dose. A person would get this amount of radiation (1 mrem) from:

  • Three days of living in Atlanta
  • Two days of living in Denver

These differences are due to differences in altitude.

Sources:

  • Frontline: Facts About Radiation
  • Hyperphysics: Meet the Millirem


  • Sleeping next to someone for 8 hours: 2 mrems. Exposure comes from the naturally radioactive potassium in the other person's body.

  • Coal plant, living within 50 miles: .03 mrem. There is a lot of thorium and uranium in coal. Living within 50 miles of a nuclear power plant adds .009 mrem of exposure, for a total of 0.039 mrem. Both figures are considered extremely low levels.

  • Living in a masonry home: 7 mrems. Stone, brick and adobe have natural radioisotopes in them.

  • Living on the Earth: 200 mrems. We are living in a sea of radon. It is made from the natural decay of uranium and thorium in the soil, left over from the creation of the solar system. Radon is a rare gas that diffuses out of soil and into the air. It contributes more than half of our background exposure.

  • Smoking: up to 16,000 mrems. The tobacco leaf acts like the absorbing surface of charcoal in a radon test kit. It collects long-lived isotopes of airborne radon, like lead-210 and polonium. Small portions of the lungs can get relatively whopping doses, compared to background levels.

  • Porcelain teeth or crowns: tenths of a rem. Uranium is often added to these dental products to increase whiteness and florescence.

  • Air Travel: 1 mrem per 1000 miles. 30,000 feet above the ground you're closer to the ionizing radiation (high-energy gammas well as particles) from the sun.

  • Grand Central Station, NYC: 120 mrem for employees. Its granite walls have a high uranium content.

  • Brazil Nuts: This is the world's most radioactive food due to high radium concentrations 1000-times that of average foods.

  • The US Capitol Building in Washington, DC: This building is so radioactive, due to the high uranium content in its granite walls, it could never be licensed as a nuclear power reactor site.