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dence suggests that UV exposure should be avoided and that even low UV doses
can be harmful.
UV MEDs
MED (Minimum Erythemal Dose) is defined as the amount of sunlight exposure neces-
sary to induce a barely perceptible redness of the skin within 24 hours after sun expo-
sure. In other words, exposure to 1 MED will result in a reddening of the skin. Because
different skin types burn at different rates, 1 MED for persons with very dark skin is
different from 1 MED for persons with very light skin.
Both the U.S. Environmental Protection Agency (EPA) and Environment Canada have
developed skin type categories correlating characteristics of skin with rates of sunburn.
T
ABLE
A-1: EPA S
KIN
P
HOTOTYPES
Skin Phototype
Skin Color
Tanning & Sunburn history
1 - Never tans,
always burns
Pale or milky white;
alabaster
Develops red sunburn; painful swelling,
skin peels
2 - Sometimes tans,
usually burns
Very light brown;
sometimes freckles
Usually burns, pinkish or red coloring
appears; can gradually develop light
brown tan
3 - Usually tans,
sometimes burns
Light tan; brown, or
olive; distinctly
pigmented
Rarely burns; shows moderately rapid
tanning response
4 - Always tans;
rarely burns
Brown, dark brown, or
black
Rarely burns; shows very rapid tanning
response
