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Titel |
Utilising shade to optimize UV exposure for vitamin D |
VerfasserIn |
D. J. Turnbull, A. V. Parisi |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 11 ; Nr. 8, no. 11 (2008-06-02), S.2841-2846 |
Datensatznummer |
250006177
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Publikation (Nr.) |
copernicus.org/acp-8-2841-2008.pdf |
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Zusammenfassung |
Numerous studies have stated that humans need to utilise full sun radiation,
at certain times of the day, to assist the body in synthesising the required
levels of vitamin D3. The time needed to be spent in the full sun
depends on a number of factors, for example, age, skin type, latitude, solar
zenith angle. Current Australian guidelines suggest exposure to
approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on
age, would be appropriate to provide adequate vitamin D3 levels. The
aim of the study was to determine the exposure times to diffuse solar UV to
receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in
order to assess the possible role that diffuse UV (scattered radiation) may
play in vitamin D3 effective UV exposures (UVD3). Diffuse and
global erythemal UV measurements were conducted at five minute intervals
over a twelve month period for a solar zenith angle range of 4° to
80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED,
solar zenith angles smaller than approximately 50° can be utilised for
exposure times of less than 10 min. Spectral measurements showed that,
for a solar zenith angle of 40°, the UVA (315–400 nm) in the diffuse
component of the solar UV is reduced by approximately 62% compared to the
UVA in the global UV, whereas UVD3 wavelengths are only reduced by
approximately 43%. At certain latitudes, diffuse UV under shade may play
an important role in providing the human body with adequate levels of
UVD3 (290–315 nm) radiation without experiencing the high levels of UVA
observed in full sun. |
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