National Oceanography and Atmosphere Administration
As
described in other sections of the UV information,
the UV Index is a forecast of the probable intensity of skin
damaging ultraviolet radiation reaching the surface during
the solar noon hour (11:30-12:30 local standard time or 12:30-13:30
local daylight time). The greater the UV Index is the greater
the amount of skin damaging UV radiation. How much UV radiation
is needed to actually damage one's skin is dependant on several
factors. But in general the darker one's skin is, (that is
the more melanin one has in his/her skin) the longer (or the
more UV radiation) it takes to cause erythema (skin reddening).
Figure 1 shows a look up chart where by one can cross check
his/her propensity to burn versus the UV Index. For those
who always burn and never tan the times to burn are relatively
short compared to those who almost always tan.
The
EPA has devised general guidelines as far as what to do to
protect oneself from overexposure to UV radiation. These are
shown in the table below.
Exposure
Category |
UV
Index |
Protective
Actions |
Minimal |
0,
1, 2 |
Apply
skin protection factor (SPF) 15 sun screen. |
Low |
3,
4 |
SPF
15 & protective clothing (hat) |
Moderate |
5,
6 |
SPF
15, protective clothing, and UV-A&B sun glasses. |
High |
7,
8, 9 |
SPF
15, protective clothing, sun glasses and make attempts
to avoid the sun between 10am to 4pm. |
Very High |
10+ |
SPF
15, protective clothing, sun glasses and avoid being in
the sun between 10am to 4pm. |
Figure
1
Return
to UV Index
Last
Updated September 2, 1997 by Craig
S. Long
|