Sun Safety

After a long Canadian winter, our first impulse is to soak up sun while we can. However, long-term sunlight exposure and multiple or severe sunburns are major risk factors for skin cancer. If you have fair skin or lots of freckles and moles, you are even more at risk. Children are also more likely to suffer long-term damage from exposure, as their skin is thinner and more sensitive than an adult's.

Sunlight contains a spectrum of ultraviolet radiation. UVA and UVB rays are of most concern. Ultraviolet rays do not need to burn you in order to do damage. Over time, sun exposure can harm the skin's cell structure and function.

• UVB rays are the most powerful and harmful. They cause sunburn, surface skin aging and are linked to the development of cancer and cataracts. They are stronger between late morning and early afternoon when the sun's rays are directed straight down at the earth.
• UVA rays are naturally more abundant and penetrate deeper to damage skin, causing structural skin aging. They also contributes to the development of skin cancer. UVA radiation is relatively constant year round, and stronger in the early morning and late afternoon when the sun reaches the earth at an angle.

UV Intensity

• The sun is most intense between 10am and 4pm, and especially close to mid-day.
• Skiers, hikers, and mountaineers should note that UV radiation increases about 10% for every 1000m of elevation gain.
• Fresh snow can reflect up to 85% of UV rays. Water reflects about 10%.
• Clouds reduce, but do not eliminate UV exposure. Light or variable cloud cover (when the sky remains bright) reduces radiation by 10 to 20%. Heavy dark clouds reduce it by 50 to 80%.
• Depletion of the ozone layer increases the amount of UV that penetrates the atmosphere. In Canada, ozone degradation is worst in late summer and early fall.
• When travelling, be aware that anti-malaria drugs such as Doxycycline can increase UV sensitivity. Tetracycline antibiotics, often used to treat infection, can cause photosensitivity at high elevations.

Protective Clothing

Some MEC-brand garments have a UPF (Ultraviolet Protection Factor) rating. The higher the rating, the higher the level of protection from UVA and UVB rays. These are voluntary standards set by the American Society for Testing and Materials (ASTM) offer a relative indication of the level of protection you can expect.

Some UV-protective garments are treated with compounds, fluorescent brighteners, or specially treated resins that absorb UV rays. According to the ASTM, a garment with a UPF treatment must undergo 40 simulated launderings, withstand the equivalent of two years' exposure to sunlight, and (for swimwear) be exposed to chlorinated water.

A new cotton T-shirt without a UV treatment offers a UPF of about 15. In general garments with a tighter weave or knit provide higher levels of protection. Clothing that is damaged, worn, wet, or stretched is less effective at blocking UV rays.

Sunscreen

The SPF of sunscreen refers to the duration of time a product may offer protection, not a level of intensity. In ideal conditions a product with an SPF of 15 may allow you to extend the time of exposure before burning considerably. However, a product with an SPF of 30 is not twice as strong, nor will it last twice as long as a product labelled SPF of 15. How long a product protects your skin is a function of skin type and activities like sweating and swimming.

• Most people benefit from sunscreens with an SPF of 15 or more.
• Some sunscreens, called broad spectrum, claim to block both UVA and UVB. However, no sunscreen blocks all UVA. There is currently no standard system for rating UVA protection.
• Do not use sunscreen on infants under 12 months, keep them shaded with clothing and a hat, and keep them out of the sun.
• Apply sunscreen 15-30 minutes before exposure or before applying insect repellent.
• Re-apply every two hours, regardless of any performance claims listed on the product. For climbers or endurance athletes who can't stop every two hours we recommend a product with an SPF of 45 or 60 which offer a higher initial chemical load, thus a slightly higher grade of protection.