Uva uvb uvc wavelength
These regions were determined by the transmission properties of three common glass filters a barium-flint filter defined the UVA (315-400nm) a barium-flint-pyrex filter the UVB (280-315nm) and a pyrex filter defined the UVC (wavelengths shorter than 280nm). Source & ©: SCCP "Opinion on Biological effects of ultraviolet radiation relevant to health with particular reference to sunbeds for cosmetic purposes (2006)" 3.2(a), p.12Ģ(b) What are the differences regarding the health and safety risks with respect to exposure of persons to UVA, UVB and UVC radiation respectively?Ĭoblentz introduced the concept of the spectral regions UVA, UVB and UVC at the Second International Congress on Light in Copenhagen in 1932. The earliest study suggested an elevated risk associated with exposure to fluorescent lights at work (Beral et al,1982) but all subsequent studies failed to identify such a risk (Osterlind et al, 1988 Rigel et al,1983 Walter et al, 1992 Holly et al, 1995).
Household lights emit significant amounts of UVR (Sayre et al, 2004) and several case-control studies have addressed risk for melanoma associated with such exposure.
#UVA UVB UVC WAVELENGTH SKIN#
It is likely, from our knowledge of skin cancer and solar UVR, that the skin cancer risk attributable to artificial UVR will be greater in those who are genetically susceptible such as the fair skinned. Overall, the risks of skin cancer from the medicinal use of artificial UVR (in the absence of photosensitizers) appear to be small but the data are few and the dose to which the patients are exposed tends to be significantly smaller than users of commercial sunbeds are potentially exposed to. A study in Scotland with a median follow up period of 4 years has shown a small increase in BCC after treatment with narrow band UVB phototherapy (Man et al, 2005). This was an in situ melanoma which developed in the same year that narrow band UVB therapy was begun (Weischer et al, 2004). In an even smaller study of 195 German psoriatics treated with broadband (n=69) or narrow band UVB (n= 126) from 1994 to 2000 only one skin cancer had occurred by 2004. In a study of psoriatics treated with coal tar and UVB in the 1950s followed up for 25 years there was no demonstrable increased risk of skin cancer but the numbers treated were relatively small (280) (Pittelkow et al, 1981). In the PUVA cohort study reported by Stern from the United States, there was no discernable additional effect of exposure to UVB (Stern and Laird, 1994).
#UVA UVB UVC WAVELENGTH PLUS#
The use of psoralen plus UVA (PUVA) to treat psoriasis is known to cause skin cancer (Stern and Laird, 1994) but PUVA is mechanistically quite different from UVA and UVB and therefore is not relevant to the current discussion. Photo(chemo)therapy is used in the treatment of skin diseases. Although the UVR dose is considerably lower than that to which users of tanning devices are potentially exposed, such studies do have the merit of much more accurate dosage estimation. There are some data published on the effects of medical use of artificial UVR sources. Many studies therefore have recorded only whether a tanning device has been used “ever” or “never” so that the power to address dose or age effects is limited.įurthermore, tanning device users are often those who sunbathe frequently and it is likely that case-control studies are seriously confounded. There are also great difficulties in collecting adequate exposure data because of recall bias and lack of user knowledge of the type of UVR emitted by the devices. Furthermore the tanning device studies are often uninformative because of small numbers of cases and controls, and low usage of the devices. It is much more difficult to compare chronic effects which, in the sun, also depend on patterns of exposure.ĭata on the risk of skin cancer associated with artificial UVR sources (see Section 4) are few compared with those related to sun exposure. It is relatively easy to compare the acute risks of exposure to natural and artificial UVR, which are similar, the details of which are discussed in Section 4. Emission spectra of solar UVR and two tanning lamps