Minimum Erythemal Dose
The minimum erythemal dose (MED, J.m-2) is defined as the erythemal radiant exposure that produces a just noticeable erythema on a single individual's previously unexposed skin. This measure is subjective with regards determination of the reddening of the skin and depends on many variables including individual skin pigmentation and exposure site. Where MED is used in populations of different skin types, it must be defined for skin type, it use is therefore limited.
Standard Erythemal Dose
The standard erythemal dose (SED, J.m-2) is equivalent to an erythemal radiant exposure of 100 J.m-2. The SED is independent of skin type and a particular exposure dose in SED may cause erythema in fair skin but none in darker skin.
Two units of type "dose equivalent."
http://support.bentham.co.uk/support/solutions/articles/5000619299-erythemal-radiant-exposure-and-uv-index
Minimum Erythemal Dose The minimum erythemal dose (MED, J.m-2) is defined as the erythemal radiant exposure that produces a just noticeable erythema on a single individual's previously unexposed skin. This measure is subjective with regards determination of the reddening of the skin and depends on many variables including individual skin pigmentation and exposure site. Where MED is used in populations of different skin types, it must be defined for skin type, it use is therefore limited.
Standard Erythemal Dose The standard erythemal dose (SED, J.m-2) is equivalent to an erythemal radiant exposure of 100 J.m-2. The SED is independent of skin type and a particular exposure dose in SED may cause erythema in fair skin but none in darker skin.