Background Radiation Explained

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Background radiation is the low-level naturally occurring radiation that is found all around the Earth. Background radiation comes from cosmic rays, radon gas, x and gamma rays, food and drinks. Background radiation is generally safe for humans.

This information is relevant for Edexcel Combined Science and Physics students, as well as AQA Physics (Separate Science) students. 

All other courses (AQA and OCR) do not contain material about background radiation and can skip this page. 

What is the Largest Source of Background Radiation?

The largest source of background radiation in the UK is radon gas. This is a gas that is naturally occurring and is made when uranium decays. This is a common process by which some of the radioactive isotopes of elements are converted over time to other lighter elements that have fewer protons and neutrons in their nuclei. 

Other important sources of background radiation include:

Medical treatments and diagnoses, food, drinks and cosmic rays. 

Learn more about atomic models.

Why Does Background Radiation Vary Across the UK?

Background radiation as explained above comes from uranium-containing rocks. The amount of uranium in rocks can be explained by the differences in geology around the UK. Over hundreds of millions of years, the UK has developed into a rich diversity of rock types with all three major types represented. To see maps of these differences in geology – see this link to the British Geological Society

In general, the soils which produce sedimentary rocks and the composition of the magma that produces the igneous rocks determine the amount of radon gas that will be released, again due to the uranium content. If you are interested in geology and would like to learn more about radon gas and its origins in rocks around the UK, take a look at this paper for a high-level, detailed picture of the distribution of radon gas. 

For more information on radioactivity, check out this quiz on the types of radiation.