Radiation - Invisible energy
(ultraviolet) radiation is an invisible part of the sun's energy.
There are different kinds of ultraviolet rays based on their wavelength.
Two types that reach the earth are UVA and UVB. UVA rays go deeper
into the skin, causing wrinkles and skin aging. UVB rays cause burning
and blistering on your skin.
of UV radiation; Good news & Bad news
sunlight is the source of the all life on earth. It lights up the
earth and gives the solar energy to plants and animals to live.
Also it assists in the production of vitamin D in skin cells. This
vitamin is essential for the growth and development of healthy bones.
tell us that a small amount (10 - 15 minutes per day) of sun exposure
is good for health, but sun overexposure can lead to a number of
serious health problems, including malignant melanoma, other skin
cancers, eye cataracts, weakening of the immune system, and premature
aging of the skin. With reduced ozone protection, increased levels
of UV radiation are reaching the earth's surface.
influencing UV Radiation
of day: When the sun is highest
in the sky, UV radiation is intense.
of year: The sun is strong in summer,
intermediate in spring and fall, and lowest in winter. UV rays are
also reflected by sand and water, even
in winter, sun overexposure can occur because ice and
snow reflect a large amount of UV radiation.
conditions: It is true that there is less UV radiation on
a cloudy day, but clouds cannot absorb
one hundred percent of the harmful rays. Sometimes clouds
increase the UV radiation through reflecting it.
Generally, the further away
from the equator, the less amount of UV radiation.
The amount of UV radiation increases significantly with altitude
because there is less atmosphere to absorb the UV radiation.
conditions: Thicker ozone provides better protection from
UV radiation and the thickness of the ozone layer varies by season
UV index, developed by the National Weather Service and the Environmental
Protection Agency, is a new component for local weather forecasts
that predicts tomorrow's likely levels of exposure to UV radiation
and also indicates the degree of caution you should take outdoors.
The UV index predicts UV levels on a 0 to 10+ scale. The lower number
means less exposure.
information on UV
index, what it is, how it is calculated, and UV crossword puzzle,
is provided by the Environmental Protection Agency Web site.