Interrelation of atmospheric ozone and cholecalciferol (vitamin D3) production in man.

Mean atmospheric ozone levels have increased steadily in the last 25 years, and this is likely to have decreased the amount of UVR reaching the earth's surface. Vitamin D3 formation in man depends on the UV irradiation of a precursor in the skin, and so we have used a computer, and the action spectrum for D3 production, to calculate the probable reduction in vitamin D3 formed by the human skin as a result of the increased ozone levels. We estimate that in the period from 1951 to 1972 the total vitamin D accumulation by the body might have thus been reduced by 15%.