What is UV radiation?
The sun emits light (visible radiation), heat (infrared radiation) and UV radiation (invisible to the eye and touch). UV radiation can be further broken down in to its different wavelengths of UVA, UVB and UVC. Short-wavelength UVC is the most damaging type of UV radiation. However, it is completely filtered by the atmosphere and does not reach the earth's surface.Medium-wavelength UVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning. The relatively long-wavelength UVA accounts for approximately 95 per cent of the UV radiation reaching the Earth's surface. It can penetrate into the deeper layers of the skin and is responsible for the immediate tanning effect.
Why do i need to protect against UV radiation in the winter?Normally you don't, but if you are going on a skiing holiday or mountaineering then you need to protect yourself. At altitude there is less atmosphere to filter UV rays. With every 1000m , UV intensity increases by 10-12%. So your skin can burn more quickly on the slopes than at sea level. Snow reflects around 85% of the sun's UV rays so you may burn in unusual places. Look out for the underside of your chin and your ears in particular. Up to 80% of the sun's UV rays penetrate light clouds, and what gets through can reflect back and forth between the clouds and the snow. So even if it's cloudy it's important to protect yourself.
Protecting against UV radiation?