UV Monitoring
Published: Wednesday, July 23, 2008
One of the major health concerns is the amount of harmful UV radiation reaching the ground. To report the UV-Index accurately for public information requires quite sophisticated instruments. Only Kipp & Zonen produces both these and the software necessary to correct the data for atmospheric effects.
The Ultraviolet (UV) part of the solar spectrum has several beneficial effects for human biology, but too much can be very harmful. The UV region covers the wavelength ranges 100-280 nm (UVC), 280-315 nm (UVB) and 315-400 nm (UVA). All UVC and approximately 90 % of UVB from the sun is absorbed by the earth’s atmosphere.
UV radiation helps to produce vitamin D, but it can also burn the skin and cause cancers, melanoma and cataracts. The short wavelength UV-B radiation is especially dangerous. Biological material that is exposed to it, tends to become damaged and degrade, including human skin. UV reflected from the ground, snow and sea is equally dangerous. We are very sensitive to small changes in the amount of UVB and this varies a lot, depending on altitude, the height of the sun in the sky, the amount of Ozone in the atmosphere and cloud cover.
The Global Solar UV Index is an indicator of UV exposure and its possible detrimental effects. The UV Index (UVI) serves as an important vehicle to raise public awareness and to alert people about the need to adopt protective measures when outdoors. The human skin’s response is not the same at all wavelengths. UVI should only be derived from radiation intensity measurements made according to the action spectrum for UV-induced erythema on the human skin (UVE) that is defined by ISO.
Many countries nowadays have some sort of UV monitoring program. Often this program is also extended to providing public information about the exposure risk level. For this kind of monitoring, the Kipp & Zonen UVS-E-T is the most suitable choice. It measures UV radiation with the same response as human skin and is ideal for calculating the UV-Index.
‘Holes in the Ozone layer’ are areas of stratospheric Ozone depletion. These are indicators of the general health of the atmosphere and let through more harmful UV to the ground. They are not confined to the North and South Poles. The Kipp & Zonen ‘Brewer’ spectrophotometer forms the basis of the global Ozone and UV database and is the ultimate instrument for UVA, UVB, UVE and UVI measurements with correction for atmospheric Ozone and Sulphur Dioxide. The Brewer is the best reference for a network of broadband UV radiometers such as our UVS-E-T.