INDOOR TANNING OFFERS
CONTROL
Indoor tanners are at a great advantage by having access to the control that
goes into the indoor tanning process. In addition to various state and local
regulations in place, national guidelines set by the Federal government enhance
the controllable factors involved in indoor tanning. Since 1986, Federal
Performance Standards for tanning devices have been in place to cover and
control many of the following aspects of indoor tanning:
-Timer control
-Protective eyewear
-Temperature control
-Electrical safety
-Protection from lamps
-Equipment access and support, and more
VARIABLES INVOLVED IN OUTDOOR TANNING
Outdoor tanners are at the mercy of many uncontrolled elements. Here is
an example of a few things to consider if tanning outdoors:
1. Solar elevation (height of the sun in the
sky)
The intensity of outdoor ultraviolet light (the
sun), and especially UVB, depends on the height of the sun in the sky. This will
vary depending on the season of the year, time of day and latitude in which you
live. UV intensities are highest during the summer months in the 4-hour period
around noon (or 13:00 if daylight saving is in effect).
UVB intensity varies more with the time of the
day than does UVA. As a rule of thumb "when your shadow is shorter than your own
height" you may receive half or more of UVB during the 4 hours around solar noon
on a clear summer day. In summer at noontime, UVB is two to three times more
intense in equatorial areas than in northern Europe. At about 600
latitude the total UVB exposure during the months of January and February can be
less than one clear day's exposure around midsummer.
2. Latitude and Altitude
The UV intensity at the earth's surface is
related to the angle at which the UV rays pass through the atmosphere. In the
tropics (close to 00 latitude, or near the equator) solar UV is more
intense because it has less distance to travel through the atmosphere to the
earth's surface.
UV intensities increase with altitude. This is
because the amount of atmosphere available to absorb UV is reduced, and so more
and shorter wavelength UV is able to reach higher altitude areas. In high
altitudes, skiers can be exposed to higher intensities of UV, especially as snow
is an excellent reflector.
3. Atmospheric Scattering
Solar UV is composed of direct and scattered
radiation. The sky looks blue because the blue rays from sunlight are highly
scattered by the atmosphere. UV is scattered even more than blue light, and this
can lead to an increase in a person's exposure.
4. Clouds and Haze
UV intensities are highest under cloudless
skies. Clouds generally reduce UV intensity, but light or thin clouds have
little effect and under certain conditions may even enhance the UV intensity.
Hazy days generally have higher amounts of water vapor; UV scatter in the
atmosphere increases and can result in a higher personal UV exposure. Thus, even
though haze or cloud cover can cause one to feel cooler, the UV exposure can
still be high.
5. Ground reflection
The reflective properties of the ground have an
influence on UV exposure. Most natural surfaces such as grass, soil and water
reflect less than 10% of incident UV. However, fresh snow strongly reflects
(80%) UV. During spring in higher altitudes, under clear skies, reflection from
snow could increase UV exposure levels to those encountered during summer. Sand
also reflects (10-25%) and can significantly increase UV exposure at the beach.
Reflected UV is a key source of exposure to the
eye. Acute effects, such as snow-blindness while skiing or photokeratitis at the
beach, can result from UV reflected from snow or sand respectively.
