University of Delaware
Office of Public Relations
UpDate - Vol. 16, No. 18, Feb. 6, 1997
Index ranges from zero to 3

     With the index, a rating of zero to three is given to each of the
400-plus cities included in the index to assess the potential of
dry, itchy skin conditions.

* A rating of zero means no problem, that relative humidity is
  not below 30 percent for three consecutive days and dry, itchy
  skin problems are not likely.
* A rating of one means conditions are mild with relative
  humidity indoors between 25 and 30 percent for three
  consecutive days. Mild to moderate dry, itchy skin problems
  are possible, particularly in people who are prone to dry
  skin, such as children and the elderly, and those who are
  atopic (allergic).
* A rating of two means conditions are moderate with relative
  humidity between 20 and 25 percent for three consecutive days
  and moderate to severe dry skin problems are possible among
  most of the general population.
* A rating of three means conditions are high, that relative
  humidity has been below 20 percent for three consecutive days
  and that severe dry skin problems are likely to occur in the
  general population.