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Science

Nuclear radiation

Most background radiation comes from natural sources, while most artificial radiation comes from medical examinations, such as x-ray photographs.

Radiation can damage cells and make them cancerous.

Radiation also has many practical uses. It can be used in medicine to trace where certain chemicals collect in the body, and also in industry, to control measuring equipment.

Background radiation

Background radiationradiation: Energy carried by particles from a radioactive substance, or spreading out from a source. is all around us. Some of it comes from natural sources and some comes from artificial sources.

Natural sources

Natural sources of background radiation include:

  • Cosmic rays - radiation that reaches the Earth from space
  • Rocks and soil - some rocks are radioactive and give off radioactive radon gas
  • Living things - plants absorb radioactive materials from the soil and these pass up the food chain

For most people, natural sources contribute the most to their background radiation dose.

50% radon gas from the ground, 12%  buildings and the ground, 12% food and drink, 12% cosmic rays, 14% artificial sources - mainly cosmic rays, small amount of nuclear power and weapons test

Average contribution of different sources to natural background radiation

Artificial sources

There is little we can do about natural background radiation. After all, we cannot stop eating, drinking or breathing to avoid it!

However, human activity has added to background radiation by creating and using artificial sources of radiation. These include radioactive waste from nuclear power stations, radioactive fallout from nuclear weapons testing and medical x-rays. Move your mouse over the diagram to check your understanding of this:

Artificial sources account for about 15 per cent of the average background radiation dose. Nearly all artificial background radiation comes from medical procedures such as receiving x-rays for x-ray photographs.

Back to Atoms and radiation index

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