It's definitely UVB. http://en.wikipedia.org/wiki/Vitamin_D#Production_in_the_skin http://en.wikipedia.org/wiki/Vitamin_D#Production_in_the_ski... http://lpi.

It's definitely UVB. http://en.wikipedia.org/wiki/Vitamin_D#Production_in_the_skin http://en.wikipedia.org/wiki/Vitamin_D#Production_in_the_ski... http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/ http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/ http://www.ncbi.nlm.nih.gov/pubmed/19812604 http://www.ncbi.nlm.nih.gov/pubmed/19812604