On average, how much radiation do Americans receive annually?

• A. 100 mrem
• B. 300 mrem
• C. 620 mrem
• D. 1000 mrem

Answer: (C)

The average annual radiation dose that Americans receive is approximately 620 millirems (mrem). This figure includes all sources of radiation exposure, such as natural background radiation from cosmic rays, terrestrial sources, radon gas, and man-made sources like medical imaging and radiation treatments.

Natural background radiation is the largest contributor, with radon being a significant component. In addition to this, medical procedures, particularly X-rays and CT scans, also add to the total exposure. The 620 mrem figure reflects a comprehensive look at the various sources of radiation that individuals commonly encounter in their daily lives, making it a salient benchmark when discussing radiation safety and health.

Other options reflect estimates that may not consider the totality of both natural and man-made radiation exposures. Therefore, the choice of 620 mrem accurately encapsulates the average annual dose Americans typically receive from all radiation sources combined.