UV radiation, high energy visible light and photo protection UV radiation is subdivided into three bands, UVA (320-400nm), UVB (290-320nm) and UVC (200-290nm). UVA is often further subdivided into UVAII (320-340nm)and UVAI (340-400nm) bands. UVC is completely absorbed by stratospheric ozone.
The total flux of UVA at the earth’s surface vastly exceeds that of UVB. UVB and UVA have well-studied but differing detrimental effects on the skin and materials. The need for protection against both UVB and UVA radiation to prevent skin cancer and degradation of materials is well recognised.