I believe we are here in a "plant" forum......and that is different from an "animal" forum......ooohhh...sorry....that too is prolly beyond your mental capacity...my apologies.....and just in case you haven't started to read yet and research is foreign to you....uvb is not the only problem with uv spectra light.....to animals OR plants.
Twenty years ago virtually nothing was known about the effects of UVR on plants (Teramura 1986). Even today knowledge is principally limited to the effects on agricultural crops; little is known of the effects of UVR in other natural ecosystems such as forests, meadows, savannas, tundra and alpine areas (Tevini and Teramura 1989).
The responses of plants to UV irradiation include physiological, biochemical, morphological and anatomical changes. Clearly more information is needed before a reliable assessment can be made on whether changes in ambient UVB are likely to affect significantly productivity.
And regarding sunburn......Recent studies (Parrish et al 1982, Gange et al 1986) have extended determination of the erythema action spectrum up to 400 nm and have shown that the erythemal effectiveness of UVR decreases with increasing wavelength through the ultraviolet spectrum, although the rate of change of effectiveness is much less from 330 to 400 nm, than from 300 to 330 nm.
A large number of published erythema action spectra were subject to statistical analysis and combined to produce the reference action spectrum (McKinlay and Diffey 1987). This action spectrum has been accepted by both the Commission Internationale de l'Eclairage (CIE) and the International Electrotechnical Committee (IEC), and has been shown to predict accurately the erythemal effectiveness of several polychromatic light sources differing greatly in spectral composition (Urbach 1987).
Although it can be seen that UVA radiation is much less erythmogenic than UVB radiation--broadly speaking by a factor of 1000--the much higher UVA irradiance present in sunlight means that in summertime UVA radiation contributes about 15-20% to the sunburn reaction.