Amidst all the hype and hysteria over "nuclear disasters", it's helpful to consider some actual numbers and effects.

"Nuclear radiation" is nothing new. We get it from many natural sources every day (sun, rocks, cosmic rays etc.), and have for all our lives. So did Mozart, George Washington, Julius Caesar, Emperor Chin, and Alley Oop the cave man.

Keep the following numbers in mind next time you hear hysterical reports of Japanese citizens being exposed to a whopping 20 microseiverts of radiation from the damaged nuclear plant.

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http://www.fox6now.com/news/la-fg-ra...0,386338.story

You're being exposed to radiation -- but it's the amount that counts

6:50 a.m. CDT, March 15, 2011

Everyone is exposed to some radiation. It's the level of exposure that determines whether there's any harmful effect.

But how much radiation is a lot? Here are a few numbers for comparison.

(A microsievert is a unit that measures the biological effects of radiation.)

* One year's worth of exposure to natural radiation from soil, cosmic rays and other sources: 3,000 microsieverts

* One chest X-ray: 100 microsieverts

* One dental X-ray: 40-150 microsieverts

* One mammogram: 700 microsieverts

* CT scan (abdomen): 8,000 microsieverts

* Full-body airport X-ray scanner: 0.0148 microsieverts

* Airplane flight from New York to Los Angeles: 30-40 microsieverts

* Smoking a pack a day for one year: 80,000 microsieverts

* Average dose to people living within 10 miles of 1979 Three Mile Island accident: 80 microsieverts

* Average radiation dose to evacuees from areas highly contaminated by the Chernobyl disaster: 33,000 microsieverts (Of 600,000 of the most-affected people, cancer risk went up by a few percentage points -- perhaps eventually representing an extra 4,000 fatal cancers on top of the 100,000 fatal cancers otherwise expected.)

* Limit on whole-body exposure for a radiation worker for one year: 50,000 microsieverts

Sources: TSA (APL report); CDC; FDA; NRC; ANS; IAEA; Wright State University in Dayton, Ohio
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