UVC is used for killing pond scum, sterilizing medical instruments and purifies air. Narrow band UVB is effective treatment for skin ailments including psoriasis. UVA, well, next time you hear you neighbor’s bug zapper harvesting a big one, think of how lucky we are. Black lights produce some visible light creating that wonderful effect on your velvet Elvis fluorescent painted piece of art but it’s the light below 400nm that many bugs can see and we cannot.
Unnaturally produced light can emit undesirable radiation. Incandescent lamps convert very little electricity to light and most of the light is far away from the violet end of the spectrum so little or no UV. LEDs manufactured for solely lighting purposes emit no harmful UV radiation but fluorescent lamps are a different story.
How does a fluorescent lamp produce UV? The lamp is filled with an inert gas (argon) and mercury to allow the electric arc to follow from one end of the tube to the other. When energized the gas creates UV light invisible to the human eye. The visible light emitted by a fluorescent lamp is due to the phosphor coating (white powder) applied to the inside of the glass tube – fluorescing or reacting to the excited gas.
The visible light is useful but the invisible – or UV – light can be detrimental to textiles, paints, coatings, etc. not only causing color shifting (fading) but also degradation of the structure of the materials. Use of UV filtering tube guards eliminates nearly all of the harmful UV energy so protect your valuable items from sunlight or unprotected fluorescent lights.