RADIATION
Radiation is natural. It's in our food, in the air, water, and soil. It's even in our bodies. It comes from unstable atoms-tiny particles of matter. As these atoms break up, they produce invisible energy waves or particles. Our bodies absorb a small amount of this radiation every hour, every day, every week.

More than 80 percent of the radiation we are exposed to comes from such natural sources as sunlight, soil, and certain types of rocks.

Cosmic rays filtering down through the atmosphere, and radon gas filtering up through the soil, are sources of natural radiation. This radiation is called background radiation. It is present everywhere, all the time and varies greatly depending on our geographical location.

People are exposed to radiation from man-made sources such as color televisions, smoke detectors, computer monitors, and X-rays. These sources account for less than one-fifth of our total radiation exposure. But, there is no difference between natural radiation and its effects and man-made radiation and its effects.

A person taking a cross-country flight would receive about two to five additional millirem of radiation per roundtrip, depending on flight altitude and shielding on the airplane. Due to the thinner atmosphere at the altitudes involved in cross-country flights, a traveler is exposed to more cosmic radiation. Because of their occupations, airline pilots and flight attendants routinely are exposed to higher levels of radiation than many other workers. Airline crew members and frequent flyers receive annual doses on the order of between 500 and 600 millirem.

A person undergoing a full set of dental X-rays would receive about 10-39 additional millirem per set.

A person living directly outside a nuclear power facility would receive approximately one additional millirem per year.