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Matthew Hutchins' Physics of UltraViolet Light
Portions of UV Lighting
Sample Problems


Tanning was basically explained on the home page.

But relating to Germicidal and UVC I'll talk about the affects of tanning on the body and the UV Index rating and SPF rating.

UVA does not cause much damage to the skin internally, it mostly causes an aging look of the skin and can cause a rapid aging of the skin because of the destruction of collagen fibers.

UVB is the type of UV lighting that can cause most of the problems with you skin. This type of UV lighting can have such an affect as to break up you DNA structure in you cells, causing them to not function properly. This is the main cause of skin cancer in the world (specifically it causing covalent bonds to form between adjacent thymine). UVB, as well as UVA, can cause problems to the eyes and make them not function properly.

Although, UV light is not all bad. It is claimed that thousands die prematurely due to an insufficient UVB exposure. What? When UVB comes in contact with the skin it forms Vitamin D, apparently if you are going to stay out of the sun you need to drink a lot of milk!


When You go to the beach you should but on protection. The most important thing is to prevent you skin from coming in contact with UV rays. One way to do this is with "sun block." This is the thick white cream that goes on you nose that you see lifeguards wearing. This acts as a barrier between your skin and UV rays. Another thing is "sun screen." This filters some of the UV rays coming in and brings the rays down to a less hazardous level, depending on the SPF (Sun Protection Factor). The higher the SPF the less chance of damage, also there will be less of a sun tan.

Depending on the UV Index, issued by the National Weather Service, different SPF can be used. The higher the UV Index the higher SPF should be used. The UV Index is a scale of 1-11+ telling you how strong the UV radiation is for that area for that time.

Continue to Flrorescence!

İMatthew Hutchins 2005