Figure 12.31 Upper portion, Spectral irradiance of terrestrial and extraterrestrial solar radiation together with that generated by a typical UV sunlamp. The shift to lower UV wavelengths of terrestrial radiation due to ozone depletion generalised UV action spectrum for plant damage is shown. Lower portion, Relative absorption of UV radiation by nucleic acids, proteins and flavoproteins. (Original diagram M.M. Caldwell)