FACT SHEET – ULTRAVIOLET RADIATION

FAST FACTS

• Overexposure to ultraviolet (UV) radiation either from the sun or from artificial sources such as tanning beds is the leading factor in the development of skin cancers and is the most preventable cause of the diseases i.

• Excessive sun exposure in children and adolescents is likely to contribute to skin cancer in later life ii .

• UV rays can get through clouds, fog and haze. Water, sand, concrete and especially snow can reflect, and even increase, the sun's burning rays iii .

• Sun protection is recommended when the ultraviolet index is 3 and above iv .

ULTRAVIOLET RADIATION v

Ultraviolet (UV) radiation is a component of solar radiation. UV radiation levels are influenced by a number of factors. One such factor is sun elevation: the higher the sun in the sky, the higher the UV radiation level. Additionally, elements like latitude and altitude mean that closer proximity to the equator and higher attitudes result in greater the UV radiation levels. While it is expected that UV radiation levels are also highest under cloudless skies - even with cloud cover, they can be at elevated levels. The ozone also influences UV radiation levels as it absorbs some of the UV radiation from the sun yet as it is depleted, more UV radiation reaches the earth's surface. Finally, many surfaces reflect the sun’s rays and add to the overall UV exposure (e.g. grass, soil and water reflect less than 10% of UV radiation; fresh snow reflects up to 80%; dry beach sand reflects 15%, and sea foam reflects 25%).

HEALTH EFFECTS ON THE SKIN

In Canada, sunlight is strong enough to cause skin cancer, as well as accelerated skin aging, cataract and other eye diseases with overexposure vi . The risk of skin cancer today is much greater than it was 20 years ago and continues to increase vii . While it has long been thought that a small amount of UV radiation is beneficial to one’s health given the role it plays in the production of vitamin D, it is recommended that a safer way to receive vitamin D is through food and supplements viii .

Excessive UV exposure on the skin results in a number of chronic skin changes including ix :

- Malignant melanoma: a life-threatening skin cancer.

- Carcinoma of the skin: a malignant cancer, which generally progresses less rapidly than melanoma and is less likely to cause death.

- Photoageing: a loss of skin tightness and the development of solar keratosis.

PROTECTIVE MEASURES/MINIMIZING RISK

There are a number of measures that can help protect against overexposure to UV radiation. If participating in outdoor activities when the UV index is 3 or higher, it is recommended to take shade, always wear 100% UV protective sunglasses to protect your eyes and cover up with long sleeved shirts, pants, gloves and hat or visor. Also, it is important to apply sunscreen all year round to exposed skin, reapplying often as directed and using a ‘broad spectrum’ sunscreen with sun protection factor (SPF) of at least 30 x.

Vulnerable Groups:

Children and teenagers have much more sensitive skin than adults and therefore extra protection is needed if they are going to be exposed to UV radiation for long periods of time. Studies show that sunburn may increase the risk of skin cancer later in life - children should be used to wearing protective clothing and sunscreen lotion from a very early stage xi .

Weather/Seasons:

- Do not let the winter’s cold fool you; UV radiation is dramatically higher on a snowy day. Snow reflects as much as 80 per cent of UV radiation, which is much higher than the amount reflected by water or dry beach sand (10 per cent and 15 per cent, respectively) even in summer xii .

- Avoid sunbathing for the purpose of tanning, especially between 11:00 a.m. and 4:00 p.m. in the summer when the sun's rays are strongest.

- Do not think you are safe from UV exposure because the sky is cloudy - the sun’s harmful rays can get through fog, haze, and light cloud cover.

i Canadian Dermatology Association. 2010 Melanoma Fact Sheet. Available at: http://www.dermatology.ca/patients_public/info_patients/skin_cancer/2010Melanoma-factsheet_e.pdf . Accessed on February 22, 2011 ii World Health Organization. Ultraviolet Radiation and Human Heatlh. Available at: http://www.who.int/mediacentre/factsheets/fs305/en/index.html# . Accessed on February 22, 2011 iii Canadian Cancer Society. About UV Rays. Available at: http://www.cancer.ca/Canada- wide/Prevention/Sun%20and%20UV/Preventing%20skin%20cancer.aspx?sc_lang=en . Accessed on February 22, 2010 iv Canadian Cancer Society. Being Safe in the Sun. Available at: http://www.cancer.ca/Ontario/Prevention/Use%20SunSense/Using%20SunSense.aspx?sc_lang=en . Accessed on February 22, 2011 v World Health Organization. Ultraviolet Radiation and Human Health. Available at: http://www.who.int/mediacentre/factsheets/fs305/en/index.html# . Accessed on February 22, 2011 vi Canadian Cancer Society. About UV Rays. Available at: http://www.cancer.ca/Canada- wide/Prevention/Sun%20and%20UV/Preventing%20skin%20cancer.aspx?sc_lang=en . Accessed on February 22, 2010 vii Canadian Cancer Society. Sun and UV. Available at: http://www.cancer.ca/Canada- wide/Prevention/Sun%20and%20UV/Preventing%20skin%20cancer.aspx?sc_lang=en#ixzz1EhZuIdNO . Accessed on February 22, 2011. viii Canadian Dermatologists Association. Safe way to maintain adequate levels of vitamin D. Available at: http://www.dermatology.ca/media/position_statement/vitamin_d.html . Accessed on February 22, 2011 ix World Health Organization. Ultraviolet Radiation and Human Health. Available at: http://www.who.int/mediacentre/factsheets/fs305/en/index.html# . Accessed on February 22, 2011 x BC Cancer Agency. Prevention. Available at: http://www.bccancer.bc.ca/PPI/TypesofCancer/SkinNonMelanoma/default.htm . Accessed on February 22 xi Health Canada. Ultraviolet Radiation from the Sun. Available at: http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/environ/ultraviolet-eng.php . Accessed on February 22 xii World Health Organization. Global Solar UV Index: UV radiation. Available at: http://www.who.int/mediacentre/factsheets/who271/en/ Accessed February 15, 2011.