That light bulb that’s supposed to be good for the planet and your electricity bill may be bad for your eyes and skin.
Compact fluorescent light (CFL) bulbs are considered by some to be a responsible choice for energy-conscious living because:
- They produce the same amount of light as incandescent bulbs but with just one fourth of the energy use.
- They are convenient since they fit into the same light fixtures as the old, energy-hungry incandescent bulbs.
- Their energy efficiency saves you money on your utility bill.
At my house, we exchanged most of our halogen and incandescent light bulbs for compact fluorescent light bulbs. We felt good about it.
But, a recent scientific study published in Photochemistry and Photobiology took a hard look at whether CFLs are actually a good idea for our skin and eyes – and the results are disturbing!
First, some background on compact fluorescent light bulbs:
According to Homedepot.com:
Compact fluorescent light bulbs are an energy-efficient alternative to conventional incandescent bulbs. In an incandescent bulb, electric current heats a thin filament to the point that it glows. This design produces a warm, soft light, but the bulb loses most of its energy in the form of heat. In CFLs, electric current energizes argon and mercury vapor, which excites a glowing phosphor coating inside the bulb. This design loses very little energy to heat, which means it consumes much less power than an equivalent incandescent bulb.
CFLs use around 75% less electricity than an incandescent bulb with the same light output, while lasting about 10 times longer. Additionally, since CFLs produce less heat, they can help you save on cooling costs.
This means that CFLs are a practical choice for consumers who buy their own light bulbs and pay their own utility bills.
But, how do CFLs work this energy-efficient miracle?
The authors of the Photochemistry and Photobiology study explain:
Compact fluorescent light (CFL) bulbs work on the principal of excitation of Hg (mercury) vapors and production of the Hg (mercury) emission lines that are used to excite the phosphor leading to light emission in the visible range. In addition to emission of visible light, the phosphor also serves as an absorber of the UV radiation from the Hg (mercury) vapor.
Translated, this means the UV light generated in the CFL bulb is supposed to be absorbed by the phosphor coating applied on the bulb glass, and that’s what protects us from otherwise harmful UV exposure.
Recently, however, people have begun to wonder if this UV protection mechanism really works. Medical articles, mostly out of the European Union, have documented the potential for CFLs to worsen photosensitive skin conditions (allergies to UV light) and skin cancers in susceptible people. Now this new study shows that commercially available CFL bulbs actually release UV rays that can damage healthy skin cells too.
What’s the reason that the UV protection mechanism may not be working and the CFLs might be releasing UV rays?
Cracks! Yes, cracks in the phosphor coating of the bulbs allow UVC (a really bad, DNA-damaging UV ray that doesn’t even get to us from the sun) and UVA to escape from the bulb. It’s not just “cheap” bulbs either. Nope. Every bulb the investigators tested had the phosphor coating cracks that allowed UV light to escape – bad news!!
A deeper look at the issues will help you better understand what this means to you so you can make choices about your options.
Facts to consider:
- It’s the curved geometry – due to the narrowness of the CFL tubing – that places undo stress on the phosphor coating, causing it to crack. This is less of a problem with the large tube fluorescent bulbs that we’re all familiar with (and that aren’t anywhere near as convenient).
- This study was an in vitro study (meaning they tested isolated cell types in a petri dish), not a study on the skin of living humans. Intact living human skin is tougher and more complex, with better protection mechanisms. Nonetheless, this study tested for widely accepted signs of UV damage in these cells and found it after exposure of the cells to the CFLs.
- To determine if the danger from this CFL UV exposure applies in a real life setting (i.e. your desk lamp) the investigators measured UV emission from CFL desk lamp light bulbs at 2.5, 7.5, and 35cm (about 1 to 14 inches). The results showed that in under 6 hours, using the worst of the light bulbs that they tested, and at a typical working distance of 14 inches, your skin and eyes are exposed to unsafe levels of UV rays. This level was defined as the Threshold Limit Value (TLV), which is what is considered safe and allowable in regulated workplace settings.
- Incandescent bulbs did not emanate UV light and did not cause cell damage when tested in this study.
Bottom Line: My opinion is that the results have significance for your real life exposure and all of us need to pay attention to how close we sit to CFL bulbs. What’s even more disturbing to me about the data is that UVC is released from the bulbs. UVC is very powerful at damaging cell DNA. We normally don’t have to worry about UVC because even the sun’s UVC rays don’t reach us here on earth. UVC is bad news, and trust me, you don’t want UVC exposure!
The authors’ final sentence of their paper sums it up well:
… our results confirm that UV radiation emanating from CFL bulbs (randomly selected from different suppliers) as a result of defects or damage in the phosphorus coating is potentially harmful to human skin.
What am I, as a dermatologist, doing with my own CFLs bulbs?
Well, as I was typing this post I looked over at the CFL in the task light that sits about 14 inches from my face every day and replaced it with one of my old incandescent bulbs.
I’m also going to start asking my patients about the bulbs in their task lighting when I see inexplicable evidence of excessive UV exposure on their skin.
There are some additional questions that I can’t answer right now given the data and our understanding of UV light. I’m going to have to wait for more information before I can reach any additional conclusions. Questions such as:
- What about the CFL bulbs in ceiling fixtures? Are we far enough away from the bulbs so that the UV light exposure has dropped off to a negligible level?
- Does glass or plastic housing on a light fixture block enough of the harmful rays to bring the CFL bulb UV emission down to safe levels and, if so, at what distances? We know that glass blocks UVC and some forms of plastic block UVA, so the presence of protective housing may really help. Is there some magic material that can block all the UV rays that we want blocked? Sounds to me like a patent opportunity for some clever photo-science expert!
Reference: Photochem Photobiol. 2012 Jun 23. doi: 10.1111/j.1751-1097.2012.01192.x. [Epub ahead of print] The Effects of UV Emission from Compact Fluorescent Light Exposure on Human Dermal Fibroblasts and Keratinocytes In Vitro. Mironava T, Hadjiargyrou M, Simon M, Rafailovich MH.
Photo: Thanks and Gratitude to Nioxxe