SafeSun, Personal UV meter. Basic UV facts UV light is invisible and cannot be easily detected without a scientific instrument such as a SafeSun , Personal UV meter. Human skin is particularly affected by the sun's UV-B radiation. Exposure to UV-B results in reddening of skin and sunburn. The risk of skin cancer grows with every sunburn.
Physicians associate eye cataracts with UV over-exposure.
Even on a cloudy day, you can sunburn. In some cases, UV radiation can penetrate clouds, mist and fog. Staying in the shade does not provide complete protection from UV radiation. A considerable amount of UV does not come directly from the sun, but is scattered by the atmosphere. UV is scattered by the atmosphere to a greater degree than is visible light.