Solar Erythemal Radiation

A recent article in the widely read journal, Radiation Protection Dosimetry (150 [2012] 278-82) provides one more reason, as if one were needed, to grow a beard.

The abstract reads: “A dosimetric technique has been employed to establish the amount of erythemal ultraviolet radiation (UVR) protection provided by facial hair considering the influence of solar zenith angle (SZA) and beard–moustache length. The facial hair reduced the exposure ratios (ERs) to approximately one-third of those to the sites with no hair. The variation in the ERs over the different sites was reduced compared with the cases with no beard. The ultraviolet protection factor (UPF) provided by the facial hair ranged from 2 to 21. The UPF decreases with increasing SZA. The minimum UPF was in the 53–62° range. The longer hair provides a higher UPF at the smaller SZA, but the difference between the protection provided by the longer hair compared with the shorter hair reduces with increasing SZA. Protection from UVR is provided by the facial hair; however, it is not very high, particularly at the higher SZA.”

Thanks to my son, Woelke, for the reference.