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Contribution of UVA irradiance to the erythema and photoaging effects in solar and sunbed exposures

Paper ID Volume ID Publish Year Pages File Format Full-Text
30047 44457 2015 7 PDF Available
Title
Contribution of UVA irradiance to the erythema and photoaging effects in solar and sunbed exposures
Abstract

•The ratio UVA/UVB depends on the SZA and the TOC.•The UVA contribution to the solar erythemal irradiance is ∼20% at 20° and 30% at 60°.•The UVA erythemal contribution represents 50–80% in sunbeds.•The photoaging effect is 4 times larger in sunbeds than in sun.

Even though UVA irradiance had not been considered detrimental to human skin for years, nowadays it is recognized for its role in photoaging and other biological responses. The ratio UVA/UVB is about 17 at a solar zenith angle (SZA) of 20° and it is almost constant up to 60° when it rapidly increases since the UVB wavelengths (280–320 nm) are more attenuated than the UVA waveband (320–400 nm). For a constant SZA, the ratio increases with the ozone content. The UVA component of the solar erythemal irradiance ranges from 20% at 20° to 30% at 60°, whereas it varies from 50% to 80% in the two different types of measured sunbeds. Moreover, the different spectral distribution of the lamps used for artificial tanning leads frequently to high UVA doses. The biological responses related to skin photoaging (skin sagging and elastosis) could be around fourfold the equivalent solar irradiance at midday in summer midlatitudes and they can be important in unprotected UVA exposures to sunbeds. The UVA dose accumulated during the time required in reaching 1 minimum erythemal dose (MED) increases with the SZA since the exposure durations are longer. Indeed, seasonal differences in the mean UVA dose are observed due to variations in the ozone content that results in longer exposure times without erythema. Although an artificial tanning session is usually shorter than one hour, the UVA dose from sunbeds during the time for 1 MED for skin type II (250 Jm−2) can be 2–4 times larger than the solar dose, depending on the lamp spectral emission.

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Contribution of UVA irradiance to the erythema and photoaging effects in solar and sunbed exposures
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 143, February 2015, Pages 5–11
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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Full-text PDF Download
Online Support
Any Questions? feel free to contact us