|This is the time of year when we need to be more diligent about wearing sunscreen daily. We hear a lot about UVA and UVB, but do you actually know what these acronyms are? UV is for ultraviolet, one of the 3 categories of sunlight. The other 2 are visible and infra-red. Ultraviolet or UV is divided into 3 sections according to their wave lengths – UVA, UVB, and UVC.
UVC thankfully doesn’t concern us right now because it usually does not reach the earth’s surface. It is absorbed by the ozone layer. It is the shortest wave length from the sun and prolonged exposure to UVC can be fatal.
UVB can only penetrate the epidermis. UVB rays are the tanning rays which are strongest in the summer months when the earth rotates closest to the sun.
UVA were at one time thought to be safe and as a result tanning salons sprang up like mushrooms. We have since discovered that UVA actually does more damage that UVB rays. UVA rays remain same strength all year and can penetrate light clothing, wind shields, office windows, and hats. In fact they are considered to be a light x-ray.
Should you use a sunscreen or a sunblock? Sunscreens are chemical. They absorb UVA and UVB rays. Sunblocks are physical. They physically block both the UVA and UVB radiation from the skin. Both sunblocks and sunscreens are rated with SPF numbers – the Sun Protection Factor for UVB rays only. A sunscreen with a SPF of 15 will delay sunburn from occurring for 15 times (in minutes) longer than normal if using no protection at all.
To learn more about Canada’s UV Index follow the link below.
To check the Weather Network’s UV Report, follow the link below.