The study authors collected a number of CFL bulbs and measured the amount of emissions from UVA, the type of radiation responsible for skin cancer, and UVC, a type of radiation that people are exposed to mostly through artificial lighting, coming from each one. There were significant levels of UVC and UVA emitted from all the bulbs, but in general, the higher the wattage, the higher the UV radiation.
How to Shop for Low-Energy Lightbulbs
They then exposed healthy human skin cells to light from CFL bulbs and incandescent bulbs. The researchers found that the healthy skin cells reacted to CFL radiation in the same way they react to radiation from sunlight. Namely, they increased production of cancer-causing free radicals. In some cases, depending on how close the light was to the cells, they found that skin damage could happen within 30 minutes; in other cases, damage took as much as 12 hours of exposure to the lights.
So what's going on? It has to do with how these bulbs are made, says the study's lead author Miriam Rafailovich, PhD, professor in the department of material science and engineering. CFLs work with the help of mercury: You flip one on, and mercury vapor gets excited by electron beams and emits a light that produces the same sort of UV radiation from the sun. Incandescent bulbs operate off of a different technology that doesn't produce the same sort of radiation. The glass tubes of CFL bulbs are also lined with phosphors, chemicals that theoretically keep radiation from leaving the bulb. "Everything is OK as long as the phosphor is in tact. It absorbs ultraviolet radiation and prevents it from damaging you."
The problem is, twisting the glass into those curly shapes inevitably causes cracks in the phosphors, Rafailovich says, which is why they found UV radiation emitted by every CFL bulb they tested.
You won't see as high UV radiation levels coming out of those tube-shaped overhead fluorescent lights you probably have in your office, she adds, because they don't have to be twisted.
Save Your Eyes—Change Your Light Bulbs
Slathering on sunscreen at the office is a bit of an overreaction to these results, she adds, but there are ways you can protect your skin:
• Keep your desk lamps at arm's length. "You shouldn't sit closer than a foot to these bulbs," says Rafailovich. The UV rays don't spread much farther than that. That distance helps if you're using CFLs in an overhead light fixture, which is far enough away to keep them from doing much damage.
• Invest in some glass shades. Glass shades prevent UV rays from penetrating much better than plastic or cloth lampshades, she adds.
• Go au naturel. Avoid the whole lightbulb issue entirely by letting in as much natural light as possible. At home, you can hang mirrors to reflect light, brighten spaces by applying a fresh coat of soft white paint, and pull more outdoor light into your rooms by opening blinds. Throw open the shades at your office, too. Many office windows have something called a low-e coating, which helps buildings save energy and has the added benefit of blocking most of the UV radiation from sunlight.