[12.1.2.4] s_{er} (λ)

The standardized relative spectral effectiveness in producing erythema (evaluated 24 hours post-exposure) on sensitive human skin of type 1 (always burn, never tan) and type 2 (usually burn, sometimes tan).

 

s_{er}(λ) = 1.0                                             for  250 ≤ λ ≤ 298 nm

 

s_{er}(λ) = 10^{0.094(298-λ)}              for    298 < λ ≤ 328 nm

 

s_{er}(λ) = 10^{0.015(140-λ)}             for   328 < λ ≤ 400 nm

 

Note: The absolute dose required to produce a given degree of erythema varies enormously in the range 250 nm to 298 nm, especially below 280 nm. Consequently, for the sake of simplicity and as a “reference” to compare erythemal efficacy of different UV sources, a uniform spectral sensitivity was adopted for wavelengths below 298 nm.

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