Top-of-the atmosphere (TOA) and surface fluxes for UVA (top), UVB (middle), and UVC (bottom) wavelengths for 100%, 10%, 1%, and 0.1% PAL O₂ model atmospheres for all stellar hosts. We note the differences in y-axis scale for different subplots. UVA flux is only slightly shielded by O₃ so surface fluxes scale roughly with TOA fluxes. UVB flux is partially shielded by O₃ and therefore allows the GOV-hosted models to receive less surface UVB than Sun-hosted models despite higher TOA UVB due to more efficient O₃ production. UVC surface fluxes for high O₂ levels are strongly influenced by O₃ abundance due to strong UV shielding from O₃ in this wavelength range. For models with only 0.1% PAL O₂ levels all surface UV fluxes begin to converge to TOA values as the shielding of O₃ is significantly decreased. See Sect. 4.4 for full details.