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Ultraviolet rays are the component of sunlight and is divided into UV-A and UV-B and UV-C radiation. UVA rays tan skin and is due to premature skin aging. UV-B rays cause sunburn and are often associated with skin cancer and eye problems such as cataracts. UV-C rays are most dangerous. There are, fortunately, blocked by ozone layer and do not get to the earth's surface.
What is known about the UV radiation
- The intensity of solar UV radiation is affected by several factors such as the sun's altitude, latitude, altitude and reflection from the Earth's surface, concentrations of atmospheric ozone and clouds.
- Clouds reduce but not eliminate the UV radiation. Changing cloud or a thin layer of clouds allows more UV radiation to penetrate on the earth's surface.
- The thinner atmosphere at higher altitudes, blocking less UV radiation. With every 1000 meters of altitude the UV intensity increases by 10-12%.
- The intensity of UV radiation significantly increases by reflection from surfaces such as water, snow or sand. Dry beach sand can reflect up to 15-20% and sea water 10-20% of UV rays.
- To the depth of two feet below the water reaches 40% of UV radiation reaching the water.
- The intensity of UV radiation is much higher from April to September, but may be significant also in winter. Snow can reflect up to 80% of UV rays.
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