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UV Index Today provides real-time and hourly UV index forecasts for 40,000+ cities in the United States. You can search by city and state, or use the interactive map and list of states to find your local UV index and risk level.
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10-400 nanometers, shorter than that of visible light, but longer than X-rays.UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury ...
Ultraviolet (UV) radiation is a form of non-ionizing radiation that is emitted by the sun and artificial sources. The beneficial effects of UV radiation include the production of a vital nutrient, vitamin D. However, overexposure may present risks. Sunburn, premature aging, and skin cancer are all risks to overexposure.
UV levels vary mainly with the height of the sun in the sky and in mid-latitudes are highest during the summer months during the 4-hour period around solar noon. During these times the sun's rays take the most direct path to earth. In contrast, during early morning or late afternoon hours the sun's rays pass at a greater angle through the ...
Learn how UVA and UVB rays affect your skin, eyes, and health, and how to protect yourself from them. Find out the sources, strength, and comparison of these two types of UV radiation.
ultraviolet radiation, that portion of the electromagnetic spectrum extending from the violet, or short-wavelength, end of the visible light range to the X-ray region. Ultraviolet (UV) radiation is undetectable by the human eye, although, when it falls on certain materials, it may cause them to fluoresce—i.e., emit electromagnetic radiation of lower energy, such as visible light.
UV radiation comes primarily from the sun and is made up of UVA, UVB, and UVC rays. UVC rays do not reach Earth, but both UVA and UVB rays pose health risks. Learn more here.
UV-B light (290-320nm) causes sunburns with prolonged exposure along with increasing the risk of skin cancer and other cellular damage. About 95% of all UV-B light is absorbed by the ozone in Earth's atmosphere. UV-C light (100-290nm) is extremely harmful and is almost completely absorbed by Earth's atmosphere. It is commonly used as a ...
Ultraviolet light is a type of electromagnetic radiation that can cause sunburns, tans and skin cancers. Learn about the different types of UV light, how they affect living tissue and materials, and where they come from naturally and artificially.
The UV Index (or UVI) is a standard, international measure of ultraviolet radiation. Values start at zero and can rise above 10. The higher the number, the greater the potential for damage to the ...