Search results
Results From The WOW.Com Content Network
Average UV at noon 1996-2002 (European Space Agency) The ultraviolet index, or UV index, is an international standard measurement of the strength of the sunburn-producing ultraviolet (UV) radiation at a particular place and time. It is primarily used in daily and hourly forecasts aimed at the general public.
On the positive side, UV exposure enables the synthesis of vitamin D 3, which is essential for bone health [1] and potentially plays a role in inhibiting certain cancers. [ 2 ] [ 3 ] While vitamin D can also be obtained through dietary supplements, [ 4 ] UV exposure offers benefits such as enhanced subdermal nitric oxide production and improved ...
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.
UV rays, and therefore sunlight and sunlamps, are the only listed carcinogens that are known to have health benefits, [55] and a number of public health organizations state that there needs to be a balance between the risks of having too much sunlight or too little. [56] There is a general consensus that sunburn should always be avoided.
¯, the theoretical daily-average irradiation at the top of the atmosphere, where θ is the polar angle of the Earth's orbit, and θ = 0 at the March equinox, and θ = 90° at the June solstice; φ is the latitude of the Earth.
Fastest daily average: 174 km/h (108 ... On 29 December 2003, a UV index of 43.3 was detected at Chile/Bolivia's Licancabur ... (assuming a standard lapse rate) ...
In 2009, Natural Resources Canada released a report [14] describing the possible UV exposure from several types of lamps. The report states that at 3 cm distance, the recommended daily exposure to ultraviolet radiation for skin and eye damage (if looking directly at the lamp) was attained between 50 minutes and 5 hours depending on the type of ...
Photochemical immersion well reactor (50 mL) with a mercury-vapor lamp.. Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750 nm), or infrared radiation (750–2500 nm).