Most of us would fondly remember those enjoyable times under the
sun, when everything seems bright, warm and cheery. But do you know
too much fun in the sun can do more harm than good?
The sun is constantly bombarding us with a wide array of energy. On
one end there are the infra
red rays (which makes us feel hot); following closely is the
visible light range (which
helps us see things). Immediately after are the ultraviolet rays, or UV for
short.
Much hype has been placed on UV and the protection from it. But
what exactly is UV? Ultraviolet can be classified into three
groups: UVA, UVB and UVC (according to their wavelength). UVC is
mainly absorbed by the ozone layer. Little UVC reaches the Earths
surface. It is UVA and UVB that we are concerned about.
UVA is UV energy of a longer wavelength (315nm 400nm). It is the
least harmful, but it can cause aging of the skin, DNA damage and
possibly skin cancer. UVA is notoriously known as the silent
killers. UVB is UV energy of a shorter wavelength (280nm 315nm).
UVB is known to cause skin cancer. Both UVA and UVB are responsible
for sunburn the redness and burning sensation of the skin.
Sunburn. Image
courtesy of John L. Bezzant, M.D. and the Spencer S. Eccles Health
Sciences Library
To prevent UVA and UVB from harming our skin, we need a protective
layer to shield us from the rays. For those who cannot avoid (or
love!) being under the sun, sunscreen is the answer.
There are two methods of UV protection: physical vs. chemical.
Physical protection involves deflecting the UV rays via a physical
barrier. In sunscreens, this is accomplished using micronized
chemical molecules. Examples of such molecules are Titanium Dioxide and Zinc Oxide. Chemical protection
involves converting UV rays into harmless form via chemical
pathways. One such chemical is Avobenzone.
Much research has been done on the effectiveness of these chemicals
in UV protection. As of now, titanium dioxide, zinc oxide and
avobenzone remain the more popular choices of active ingredients in
sunscreens. There are also other chemicals showing promising
results. One of these is Tinosorb
M (whose effectiveness is still under evaluation).
Now that you have known about UVA and UVB, we shall discuss more
about the measurement of sunscreen effectiveness in UVA and UVB
protection in our next article.
Sun Maven Tip for the Consumer:
When looking for a good sunscreen product, be sure to check through
the ingredient list. Look for well-researched sunscreen
ingredients, such as titanium oxide, zinc oxide or avobenzone near
the front of the list. A word of caution: These chemicals should
form the main active ingredients in the product. Too little of
goodness is none at all.
Sun Maven is an up
and coming sun care products retailer in Singapore (Jan
2006).