Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness.
Vitamin D production in human skin occurs only when incident UV radiation exceeds a certain threshold. From simulations of UV irradiances worldwide and throughout the year, we have studied the dependency of the extent and duration of cutaneous vitamin D production in terms of latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude. For clear atmospheric conditions, no cutaneous vitamin D production occurs at 51 degrees latitude and higher during some periods of the year. At 70 degrees latitude, vitamin D synthesis can be absent for 5 months. Clouds, aerosols and thick ozone events reduce the duration of vitamin D synthesis considerably, and can suppress vitamin D synthesis completely even at the equator. A web page allowing the computation of the duration of cutaneous vitamin D production worldwide throughout the year, for various atmospheric and surface conditions, is available on the Internet at http://zardoz.nilu.no/~olaeng/fastrt/VitD.html and http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html. The computational methodology is outlined here.
Engelsen
Ola
O
Norwegian Institute for Air Research (NILU), Tromsø, Norway. ola.engelsen@nilu.no
Brustad
Magritt
M
Aksnes
Lage
L
Lund
Eiliv
E
D000336:Aerosols; D000531:Altitude; D003198:Computer Simulation; D006801:Humans; D020407:Internet; D008962:Models, Theoretical; D010126:Ozone; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects; D013997:Time Factors; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000096:biosynthesis*; D014887:Weather
D000336:Aerosols; D014807:Vitamin D; D010126:Ozone