What Is The Difference Between UVA And UVB Rays?


We all know about the ultraviolet radiation that originates from the sun and reaches the earth to cause various problems with the skin. This radiation is composed of three separate wavelengths. UVA, UVB and UVC. As far as the skin is concerned, UVC is inconsequential but UVA and UVB have a direct effect on photo aging, burning and tanning.

There is a lot of misinformation in reference to UV radiation and a lot of debate on the best way for the skin to receive the necessary vitamin D which is photosynthesized. What is not misinformation is that ultraviolet radiation is responsible for many skin cancers SCC (squamous cell carcinoma), BCC (basal cell carcinoma) and in most likelihood melanoma. Let’s discuss the differences and the effects.  Obviously, sun damage can lead to skin wrinkles as well.

General Facts on UVB and UVA Rays

UVA refers to the long wavelengths (320 – 400nm) and amounts to 95% of all solar radiation. It is present for as long as there is sunlight and it can penetrate deep into the skin. The recent studies have shown that UVA plays a major part in aging and wrinkling of the skin as well as the aforementioned skin cancers. While it is less intense than UVB, it is 30 to 50 percent more prevalent and capable of penetrating through glass and therefore we are all exposed to large doses of it throughout our lives.

UVB pertains to the middle range wavelengths (290 – 320nm) and until recently it was believed that it is the most damaging part of UV radiation. Thankfully it is not as prevalent as UVA, it cannot penetrate glass and the intensity varies depending on the season, the location and the time of day. Usually it is most intense between 10 a.m. and 4 p.m. and it is directly linked with the acceleration of skin aging and the development of skin cancer.

pic of UV Ray on the skinFor the record, UVC refers to the short wavelengths and is filtered by the ozone layer and does not reach the earth surface and this is why it is considered as inconsequential. However this will remain so as long as there is still an ozone layer to protect the earth. It is well known that ozone depletion is a major problem for the earth’s environmental conditions.

The most recent study that was conducted by a joint Australia-U.S. team of scientists, determined than both UVA and UVB are equally damaging to the skin. In fact UVA causes more genetic damage to the DNA and the skin cells as it penetrates deeper into the body, while UVB causes more superficial damage.

The changes in SPF

Until this recent study, SPF rating was addressing protection from UVB radiation as it was considered as more harmful. Actually it was referring to the erythema produced by UVB and the level of sunscreen protection against it. Until the results of this recent study are put in effect in the development of new sunscreens, it is important to select the appropriate products that are already out on the market.

First of all it is necessary to select a sunscreen that offers broad spectrum protection. This is indicated by the presence in the ingredients of at least one element that can protect against long wavelengths. Such ingredients are zinc oxide and avobenzone. In general it is best to look for inorganic and mineral sunscreens which do not absorb UV radiation. Instead, they reflect UV rays away from the skin.

Irreparable damage

The effects to the skin seem to be the same in both UVA and UVB with UVB being more protectable against and UVA having a lot worse long term effects and harder to defend against. The fact is that we receive a combination of both wavelengths in large doses every year and the result is cumulative and irreversible. Remaining only in the immediate effects like sunburns, spots and discoloration is like seeing only the tip of the iceberg.

Both UVA and UVB merit deeper and more extensive study which will produce more permanent results and solutions. Until that time, it is of the utmost importance to apply protection whenever we are venturing outdoors and to limit our exposure to the sun to the absolute minimum possible.

This in no way implies that we are to remain indoors. On the contrary some exposure is recommended in order to allow for vitamin D to form and help out skin. But under no circumstances are we to get out into the sun without the proper protection which includes sunglasses and hats.

If you find yourself with severe sunburn, there are a number of things you can do in order to try and lessen the pain.  Try coconut oil for sunburn as a natural remedy.  Of course, using aloe vera is a popular method as well.

What Is The Difference Between UVA And UVB Rays?
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