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"Very high" A UV index reading of 8 to 10 means very high risk of harm from unprotected sun exposure. Take extra precautions because unprotected skin and eyes will be damaged and can burn quickly. Minimize sun exposure between 10 a.m. and 4 p.m. If outdoors, seek shade and wear sun-protective clothing, a wide-brimmed hat, and UV-blocking ...
Highest ultraviolet index measured: On 29 December 2003, a UV index of 43.3 was detected at Chile/Bolivia's Licancabur volcano, at 19,423 feet (5,920 m) altitude. A light-skinned individual in such conditions may experience moderate sunburn in as little as 4 minutes.
Consider the sunburn, a deterministic effect: [4] when exposed to bright sunlight for only ten minutes [5] at a high UV Index, that is to say a high average dose rate, [6] the skin can turn red and painful. The same total amount of energy from indirect sunlight spread out over several years - a low average dose rate - would not cause a sunburn ...
Using satellite data, measurements from the European Space Agency produce similar maps expressed in units of the widely followed UV Index, for locations around the world. [27] Effects of UV-radiation at high latitudes, where snow stays on the ground into early summer and the sun then remains at a low position even at its zenith, have been ...
This page was last edited on 29 August 2007, at 07:25 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may ...
UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids such as semen, blood, and saliva. [94] For example, ejaculated fluids or saliva can be detected by high-power UV sources, irrespective of the structure or colour of the surface the fluid is deposited upon. [95]
The intensity is commonly measured by the UV Index. [8] There are two different mechanisms involved in the production of a tan by UV exposure: Firstly, UVA radiation creates oxidative stress, which in turn oxidizes existing melanin and leads to rapid darkening of the melanin.
Sunburn effect (as measured by the UV Index) is the product of the sunlight spectrum at the Earth's surface (radiation intensity) and the erythemal action spectrum (skin sensitivity). Long-wavelength UV is more prevalent, but each milliwatt at 295 nm produces almost 100 times more sunburn than at 315 nm.