Sources of Radiation
Since the beginning of time, all living creatures have been, and are still being, exposed to radiation. Nonetheless, most people are not aware of all the natural and man-made sources of radiation in our environment.
A chart of the public's exposure to ionizing radiation (displayed below) shows that people generally receive a total annual dose of about 620 millirem. Of this total, natural sources of radiation account for about 50 percent, while man-made sources account for the remaining 50 percent.
For additional information, see the following topics: