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What is radiation?

Radiation is the release of energy (rays and particles) from certain kinds of atoms.

Natural Radiation is all around us in the environment and in products and devices we use in everyday life.

It is also generated by artificial sources such as medical devices like X-ray machines , MRI and during the production of electricity from both nuclear power .

Did you know?

Health Canada provides information about radiation and its impact on health on the Government of Canada website. For more information, read the full section: Understanding Radiation.

Below is an excerpt from the Health Canada website:

Sources of radiation

Sources of naturally occurring radiation include:
• radioactive material found in rocks and soils
• cosmic radiation
• ultraviolet radiation from the sun

Radiation can also be generated by artificial sources, including:
• medical or clinical devices such as X-ray machines and ultrasound devices
• household or personal products such as microwave ovens and cell phones
• industrial or commercial equipment such as telecommunication towers and nuclear power generating stations
• fallout resulting from past military experimentation and weapons development

Ionizing radiation

As unstable atoms decay, they release radiation in the form of electromagnetic waves and subatomic particles. Some forms of this radiation can detach electrons from, or ionize, other atoms as they pass through matter. This is referred to as ionizing radiation.

Sources of ionizing radiation exposure

Every day, Canadians come in contact with ionizing radiation in their living and work environments.
Canadians are exposed to naturally-occurring radiation in the environment from rocks and soil, as well as cosmic radiation from space. These sources of radiation are referred to as "background" radiation.
Ionizing radiation can also be generated from artificial sources including medical or clinical devices, such as X-ray machines and CT scanners.

Exposure levels in Canada

The average Canadian is exposed to between 2000 and 3000 microsieverts (µSv) of radiation annually from background radiation.
Here are a few examples of radiation levels from various sources:
• A long, cross-country air flight could expose a person to about 30 microsieverts of radiation
• A CT scan can expose a person to between 5000 and 30 000 microsieverts of radiation depending on the area being scanned
• A chest X-ray could expose a patient to approximately 70 to 100 microsieverts of radiation
• A dental X-ray could expose a patient to an estimated 100 microsieverts of radiation
• A mammogram could expose a patient to an estimated 3000 microsieverts of radiation.

Non-ionizing radiation

On a daily basis, Canadians are exposed to non-ionizing radiation generated by household wiring, lighting, and electrical appliances such as microwave ovens, hair dryers, and toasters. In the workplace, common sources include computer monitors, photocopiers, fax machines, and fluorescent lights. Power lines and electric tools also a form of non-ionizing radiation. Some medical applications of non-ionizing radiation include short-wave diathermy and magnetic resonance imaging (MRI).