Ultraviolet (UV) radiation

Overexposure to UV rays can cause skin cancer, premature skin aging and weakening of the immune system.

Ultraviolet radiation comes from natural sources (the sun) and artificial sources (tanning equipment, lasers, welding equipment and certain lamps).

Ultraviolet Radiation (UVR)

Some uses of UVR include:

But, as with all forms of radiation, there are risks involved with UVR. 

Overexposure to UVR has been linked to the following negative health effects:

It is important to protect yourself when exposed to either natural or artificial UVR.

There are three types of UVR:

Ultraviolet A (UVA) rays:

Ultraviolet B (UVB) rays:

Ultraviolet C (UVC) rays (short-wave radiation):

Know the factors that affect UVR levels and learn to reduce your risk of sunburn and skin damage.

How much UVR reaches me?

You get more UVR when the sun’s rays are the strongest. The amount of UVR that reaches you depends on these factors:


Time of day

How long you’re in the sun

Position on the earth

Cloud cover



Land cover

Reflected UVR

UV Index

Environment Canada created the UV Index to let Canadians know how strong the sun’s UV rays are each day. It is a system that helps people understand what sun protective actions are recommended, based on the strength of the sun’s rays. The higher the UV Index number, the stronger the sun’s rays and the greater the need to take precautions.

When the daily UV index is 3 or higher, it can be found on The Weather Network’s website and on the Government of Canada’s website. Most daily newspapers, and television and radio weather forecasts also report the UV Index.

Remember, you can reduce your exposure to UVR in many ways:

For more information, contact the Health Unit at 705.522.9200 or 1.866.522.9200.


Canadian Centre for Occupational Health and Safety. (2020) Ultraviolet Radiation. Retrieved from https://www.ccohs.ca/oshanswers/phys_agents/ultravioletradiation.html
on July 22, 2020.

Health Canada (2017). Guidelines for Tanning Equipment Owners, Operators and Users. Retrieved from https://www.canada.ca/en/health-canada/services/publications/health-risks-safety/2017-guidelines-tanning-salon-owners-operators-users.html#a20 on August 27, 2020.

Government of Canada. Health Canada (2019). Ultraviolet Radiation. Retrieved from https://www.canada.ca/en/health-canada/services/health-risks-safety/radiation/types-sources/ultraviolet.html on July 22, 2020.

World Health Organization (n.d.). Ultraviolet radiation. Retrieved from https://www.who.int/health-topics/ultraviolet-radiation#tab=tab_1 on July 22, 2020.


This item was last modified on August 27, 2020