What is ultraviolet radiation (UV)?

The sun is the energy source that sustains all life on earth. Ultraviolet Radiation(UV) is simply one form of energy coming from the sun.

Even though you may have only just started hearing about UV and the effects it has on you, it is nothing new.  In fact, UV is as old as the earth itself.  However, research over the years has helped us to better understand how this form of energy from the sun affects us.

Cloudy days deceive many people into thinking the danger of UV radiation is minimal.  Clouds affect the strength of radiation reaching the ground in complex ways.  Most clouds block some UV radiation, but the degree of protection depends on the type and amount of cloud.  Some clouds can actually increase the UV intensity on the ground by reflecting and refracting the sun's rays.  People can also be caught unawares when a small break in an overcast deck of clouds allows a brief burst of intense radiation to reach the ground.

Cold air can also be deceptive as temperature is not directly related to UV intensity.  Skiers should take particular care as reflective snow on the ground and high altitude raise the UV Index significantly relative to its value at sea level.

What is UV Radiation?

UV Index

Effects of Sunlight

Guidelines for Protection

Sun Quiz