The ultraviolet radiation given off by compact fluorescent light bulbs (CFLs) can damage skin, according to a recent study. And while the researchers, from SUNY Stony Brook, don't suggest throwing out your compact bulbs, they do suggest using them a bit more cautiously.
Specifically, they suggest that the bulbs not be used at close distances and that they be placed behind an additional glass cover (globe or chimney) and not used as naked light bulbs.
Cells exposed to CFL bulbs grew more slowly, showed increased production of reactive oxygen species and a decrease in their ability to contract collagen, an essential part of the wound healing process.
The potential for damage comes from ultraviolet rays (UVA and UVC) produced by the bulbs. The UV escapes through small cracks in the bulbs' coating, cracks that were found in every bulb tested by the researchers.
Skin cells were exposed to the bulbs for two hours at a distance of one inch. This is equivalent to the exposure a person would get from spending 45 hours with the bulbs 14 inches away, about the typical distance from a work lamp. The bulbs were tested in a cooled enclosure where cell temperature was maintained in the 25-37˚ Celsius range, to eliminate the possibility of heat damage from the bulbs.
Exposure to incandescent bulbs did not cause any observable damage.
Some of the bulbs tested by the researchers were the pear-shaped kind that come encased in an additional glass capsule. These tested out little safer than the standard twisty CFL bulbs, with one brand testing out even more harmful.
Damage to cells increased in the presence of titanium dioxide nanoparticles, which are also found in many skin care products. Normally, titanium dioxide absorbs UV and acts as a sunscreen. But its behavior as tiny nanoparticles is less well understood and is currently a controversial topic. Here, the particles appeared to act as a photosensitizer, actually amplifying the damage from UV.
Since the UV is escaping from defects in the coating, perhaps the whole problem can be solved by bulbs that are manufactured better.
An article on the study was published online in Photochemistry and Photobiology.