Utilising shade to optimize UV exposure for vitamin D

Turnbull, D. J. and Parisi, A. V. (2008) Utilising shade to optimize UV exposure for vitamin D. Atmospheric Chemistry and Physics, 8 (11). pp. 2841-2846. ISSN 1680-7316

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Abstract

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 4o to 80o at a latitude of 27.6oS. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50o can be utilised for exposure times of less than 10 minutes. Spectral measurements showed that, for a solar zenith angle of 40o, 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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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Author(s) 2008. This work is distributed under the Creative Commons Attribution 3.0 License.
Depositing User: Dr David Turnbull
Faculty / Department / School: Historic - Faculty of Sciences - No Department
Date Deposited: 22 Jul 2008 01:39
Last Modified: 02 Jul 2013 23:04
Uncontrolled Keywords: shade; vitamin d; UV; ultraviolet radiation; diffuse
Fields of Research (FOR2008): 06 Biological Sciences > 0699 Other Biological Sciences > 069999 Biological Sciences not elsewhere classified
02 Physical Sciences > 0299 Other Physical Sciences > 029901 Biological Physics
04 Earth Sciences > 0401 Atmospheric Sciences > 040103 Atmospheric Radiation
Socio-Economic Objective (SEO2008): C Society > 92 Health > 9204 Public Health (excl. Specific Population Health) > 920401 Behaviour and Health
URI: http://eprints.usq.edu.au/id/eprint/4280

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