The dose is compared to the appropriate radiation protection standard set by Federal law. As radioactive materials decay, they emit energy in the form of rays and particles. When people are exposed to radiation, their bodies can absorb this energy, which results in a radiation dose. The amount of damage to the body depends on the type and amount of radiation absorbed. This unit expresses the potential health impact from any type of radiation.
Radiation is a natural part of our environment.
These background sources include naturally occurring radioactive materials in the environment and cosmic radiation from the sun. Radioactive materials also are in the environment as a result of past nuclear weapons testing. Recent evidence suggests that as much as two-thirds of a person's background radiation dose comes from naturally occurring radon gas, which accumulates in buildings. The amount of radiation to which a person is exposed varies according to location and lifestyle. In the Livermore area, background radiation dose is about 200-300 millirem per year.