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 EarthÂ’s 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 LibraryTo 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).