Vitamin D production in human skin occurs only when UV radiation exceeds a threshold. From simulations of UV irradiances, the VitD www page computes the daily duration of dermal vitamin D production at midday when UV radiation exceeds the required threshold. The daily duration depends on latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude all of which can be specified by the user.
Author: Ola Engelsen
Norwegian Institute for Air Research
Copyright © 2005 Ola Engelsen
Last modified September 20th 2006.
The current model has undergone internal checking and validation. If you have any questions or comments on this service and how it could be improved for your needs, please contact the author. If you use this model for your work I would be interested to know about it.
If you use this program and publish the results, I would appreciate a lot if you cite it:
Ola Engelsen, Magritt Brustad, Lage Aksnes and Eiliv Lund (2005) Daily Duration of Vitamin D Synthesis in Human Skin with Relation to Latitude, Total Ozone, Altitude, Ground Cover, Aerosols and Cloud Thickness, Photochemistry and Photobiology, 81(6), 1287-1290.
The underlying simulations are done using the following model:
Engelsen O. and Kylling A., Fast simulation tool for ultraviolet radiation at the Earth's surface. Optical Engineering, 44 (4), 041012 (2005).
Brustad, M., E. Alsaker, O. Engelsen, L. Aksnes, and E. Lund (2004) Vitamin D status in middle-aged women at 65-71 °N in relation to dietary intake and exposure to ultraviolet radiation. Publ. Health Nutr. 7, 327-335.