What is an action spectrum?
• An action spectrum is a parameter that describes the relative effectiveness of energy at different wavelengths in producing a particular biological response. “Biological response” may refer to effects at a molecular level, such as DNA damage, or at a whole organism level, such as plant growth. An action spectrum is used as a “weighting factor” for the UV spectrum to find the actual biologically effective dose (BED) for a given effect. This relation is described mathematically below, where UV and A are the ultraviolet irradiance and action spectrum values at a given wavelength (lambda), respectively. The total dose is then found by integrating over the entire wavelength range. Several action spectra are shown in the figure below: the erythemal action spectrum given by McKinlay and Diffey (1987), the mammalian non-melanoma skin cancer action spectrum of de Gruijl and van der Leun (1994); the spectrum for melanoma induction in platyfish-swordtail hybrids derived by Setlow et al., (1993)
