What does background radiation consist of?

Background radiation consists of a combination of natural and man-made sources. Natural sources of background radiation include cosmic radiation from space, terrestrial radiation from the earth, and radiometric decay of naturally occurring isotopes such as uranium and radon found in rocks and soil. In addition to these natural sources, there are also artificial or man-made sources that contribute to background radiation, such as medical procedures (like X-rays), nuclear power, and fallout from nuclear weapons testing.

The combination of these sources is what determines the overall background radiation level that people are exposed to in their daily lives. By acknowledging both natural and man-made contributions, one can understand the full scope of radiation exposure in the environment.