WE ARE OUTDOOR BEINGS
If we take evolutionary development periods as a basis, humans are outdoor creatures that have adapted to the globally very different range of radiation over many generations, for example by reducing skin pigmentation.
In comparison, the time spent indoors has increased dramatically in just a few generations, and thus too quickly for evolutionary adaptation. In post-industrial society, we currently spend over 90 percent of our lives inside buildings or vehicles.
However, the amount of radiation that prevails outdoors is comparatively strongly reduced indoors due to the properties of the transparent elements of the building envelope or is no longer available at all in some spectral ranges. There is hardly any awareness of the problems resulting from this deficiency.