Background radiation exposure rates normally vary from location to location. There are many factors that influence exposure levels, including naturally-occurring radionuclides in the soil and altitude. For example, the exposure rate from naturally-occurring elements in rocks and soils (terrestrial radiation) may vary by more than a factor of 10.
For more information about typical exposures rates, visit About Exposure and Dose Rates or the Health Physics Society’s Environmental Radiation fact sheet.Exit