Radiation is energy that comes from a source and travels through material or space. Every day, Canadians come in contact with radiation in both their living and work environments. Radiation can be classified as ionizing or non-ionizing. Ionizing radiation has sufficient energy to remove electrons from atoms or molecules. The loss of an electron results in the formation of a charged atom, called an ion. The damaging effects of ionizing radiation result from this ability to change the chemical composition of matter with which it interacts. Radiation that has enough energy to move or vibrate atoms, but not enough to remove electrons, is called non-ionizing radiation.

The Electromagnetic Spectrum

Electromagnetic spectrum displayed left to right by higher frequency, shorter wavelength to lower frequency, longer wave length. From left to right higher frequency examples are Cosmic radiation gamma radiation and X-rays (these are forms of ionising radiation); next moving toward lower frequency examples from left to right, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves (these are forms of non-ionising radiation). Pictorial examples of the types of electromagnetic spectrum are:

  • Cosmic - radiation from Outer Space
  • Gamma radiation - Nuclear Medicine treatment
  • X-ray - medical X-ray
  • Ultraviolet - radiation from the Sun
  • Visible light - a Rainbow
  • Infrared - radiant heater
  • Micro Waves - a micro wave oven
  • Radio waves - a radio broadcast

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
  • nuclear fallout resulting from past military experimentation and weapons development

Health Canada's Role:

Health Canada aims to reduce the health and safety risks associated with different types of radiation. To protect Canadians from these effects, Health Canada

  • conducts research into the biological effects of environmental and occupational radiation
  • develops better methods for internal radiation dosimetry and its measurement
  • develops regulations, guidelines, standards and safety codes pertaining to radiation-emitting devices
  • provides radiation advice and collaborates with government departments and agencies, industry, and the general public

What Information is Available?

In this section, you will find information about

  • the different types of radiation found in our environment and places of work
  • how radiation is measured and with what degree of accuracy
  • the health effects related to natural or artificial sources of radiation, including research on radionuclide metabolism
  • regulations, guidelines, standards and safety codes pertaining to radiation-emitting devices
  • the Federal Provincial Territorial Radiation Protection Committee

© "The Energy Spectrum" graphic reproduced by permission of World Nuclear Association, London, United Kingdom

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: