Ivan found this very informative article about production of the vit D dep. on the latitudes. It supports the idea we were discussed before that conscious effort should be undertaken by the people to fulfill their need in the vit. D which is a valuable substance for our body in its health needs incl. cancer protection and immune system function.
This is the link to an article:
Daily Duration of Vitamin D Synthesis in Human Skin with Relation to
Latitude, Total Ozone, Altitude, Ground Cover, Aerosols and Cloud
Thickness.
http://www.direct-ms.org/pdf/VitDGenSci ... thesis.pdf
there is link to an online tool in this article to calculate the data for your own geographical spot.
vit D
Re: vit D
Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness
Ola Engelsen et al. Photochem Photobiol. 2005 Nov-Dec.
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.
https://pubmed.ncbi.nlm.nih.gov/16354110/
Ola Engelsen et al. Photochem Photobiol. 2005 Nov-Dec.
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.
https://pubmed.ncbi.nlm.nih.gov/16354110/
Debbie