What is the average annual dose of background radiation for people in the U.S.?

• A. Over 620 millirem.
• B. About 600 millirem.
• C. About 300 millirem.
• D. About 100 millirem.

Answer: (A)

The main idea here is how much radiation people in the United States are exposed to in a year from natural and everyday sources. In the U.S., the average annual background dose is about 6.2 millisieverts, which is roughly 620 millirem. This comes from natural sources like cosmic rays, radon in homes, and minerals in the soil, plus small contributions from man-made sources that aren’t from medical procedures. Since the commonly cited figure is around 620 millirem, saying “over 620 millirem” fits that typical estimate and acknowledges slight variation among individuals and measurement methods. The other numbers are lower than what most people actually receive from background sources.