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.
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.
|40 to 50||Excellent protection|
|25 to 35||Very good protection|
|15 to 20||Good protection|
|less than 15||Not considered sun-protective|
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.
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.