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CFLs, Dirty Electricity and Bad Science

Governments and environmental advocates are promoting compact fluorescent lightbulbs (CFLs) as a way of reducing electricity use, saving money, and reducing our carbon footprint. CFLs are not a perfect technology – when turned on they take a moment to fully brighten and they contain a small amount of mercury which requires special procedures for disposal. CFLs are likely also to be a transitional technology, as more energy efficient light sources (such as LEDs) are already coming onto the market.  But CFLs are a safe and energy efficient alternative to incandescent bulbs.

It seems, however, with any new technology comes a wave of internet fearmongering, and CFLs are now a prime target. YouTube videos are circulating claiming that CFLs cause headaches, mercury toxicity, a host of symptoms from electromagnetic sensitivity, and something called “type 3 diabetes.”  Let’s take a look at the claims and the science.

Mercury in CFLs

There is a small amount of mercury in each CFL, necessary for the function of the bulb, about 4mg on average, with some newer bulbs having as little as 1.4mg. There is no exposure to mercury from using CFLs, as long as they are not broken. Even if a bulb is broken the exposure to mercury is negligible, far less than eating a tuna fish sandwich. But still, there are recommended procedures for cleaning up and disposing of a broken bulb to further minimize exposure, such as not using a vacuum, and ventilating the area. These procedures represent the cautionary principle in action, but make it easy to fearmonger about the risks of the mercury in the bulb.

According to an EPA study, only about 30% of the mercury in a CFL is released as vapor after breaking, and this occurs over a 4 day period. So a broken bulb would have to remain in a poorly ventilated area for days to reach this kind of exposure. Ventilating the room and quickly cleaning up a broken bulb is enough to reduce exposure to negligible levels.

The amount of mercury that CFLs put into the environment is actually less than the amount of mercury put into the environment by burning coal for the electricity they save. Therefore, the net effect of using CFLs is to reduce environmental mercury.

While technology that does not require the use of any toxic material is always preferred, the small amount of mercury is CFLs is not a health or environmental risk and should not discourage their use.

Ultraviolet Sensitivity

Another claims is that CFLs put out more ultraviolet light and this can cause skin reactions in those who are sensitive. Those with lupus erythematosis, for example, need to avoid exposure to UV light. It remains uncertain, however, what risk, if any, is posed by indoor lighting. Published research is mostly theoretically, concluding that indoor lamps, including CFLs generally have very low levels of UV radiation, but that long term exposure could potentially lead to a cumulative effect.

However, direct comparisons show that CFLs put out less UVA than incandescent or halogen bulbs, while putting out more UVB radiation. Further, there are CFLs available that are shielded and put out the least total UV light of all options.

For the average user, UV radiation from indoor lights does not appear to be a concern. For those with skin sensitivity long term indoor exposure may be a concern, in which case they may want to use a bulb with lower UV radiation output. There seems to be more variability within bulb types than between them, but the best option is shielded CFLs.

Headaches and Flicker Rate

There are claims that CFLs cause headaches. These claims likely stem from two sources, the first being that headaches are common. Just about every drug in existence lists headaches as a side effect, at least in a few percent of users. This is recognized as just background noise because headaches are so common. But also, older fluorescent lights (the long tubes, not the compact variety) did have a flicker of about 60 hz, and this is noticeable by some people and could cause headaches. The newer bulbs, however, use a different technology (electronically ballasted vs magnetically ballasted) and cycle at about 10,000-40,000 hz, which is not detectable. There is also no published evidence linking use of CFLs to headaches.

Dirty Electricity

The major health claim being made against CFLs, however, is that they put out “dirty electricity” which can allegedly cause a variety of health problems. There is now a video circulating on Facebook making such claims. Fear of dirty electricity goes beyond CFLs – the new bulbs are just the latest target.

Much of this seems to stem from one Canadian researcher, Dr. Magda Havas. She has dedicated her efforts to studying and warning the public about the health risks of electromagnetic radiation for years. She has become the go-to expert for the media, and her name crops up in almost every article on the subject.

This is unfortunate, because she appears to be a lone dissenting voice (some might call her a lone crank), who is often put up against the consensus of scientific opinion as if they were two equal experts. Most articles I read on the subject essentially say – some experts say electromagnetic radiation is safe, but some say that it is causing health problems, and inevitably Magda Havas is that latter expert. Meanwhile, she has published very little research, and no good research, to support her controversial claims.

For example, Havas is now talking to the media about “type 3 diabetes” as if it is a proven and accepted entity. She claims that exposure to electromagnetic radiation (including CFLs) can increase blood sugar. Her evidence is one published study, which is nothing more than a case series of four patients. Exposure to electromagnetic radiation (EMF) was often estimated (for example, assumed from working in front of a computer or using a treadmill) and not measured. There was no blinding at all to the exposure to EMF and measurement of blood sugars.

Case reports and case series are generally considered to be the weakest form of scientific medical evidence. They are one notch above anecdotes. They are used to propose new ideas for further study, but not to form conclusions. In my opinion it is irresponsible to talk to the media about the results of such research as if they demonstrate a new phenomenon. It is premature and misleading.

Regarding EMF in general, The World Health Organization recently reviewed the literature on non-ionizing radiation and found:

In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research.

Unfortunately, in popular summaries of the issue I often find that this exhaustive expert review of 25,000 studies is put up against – the opinions of Magda Havas – with the conclusion that “the experts disagree” therefore, who knows?

What about CFLs specifically? They do indeed put out more EMF in certain frequencies than incandescent or halogen bulbs, but there is no evidence that this level of EMF poses any health consequences. Further, one thing is absolutely clear – EMF falls off sharply with distance. Even after a couple of feet the EMF put out by light bulbs falls from tiny by many orders of magnitude to negligible.  The EMF intensity at a distance of inches (as shown in the Facebook video) is irrelevant.

Conclusion

The notion that EMF or dirty electricity causes a health risk, and that CFLs are a significant source of exposure, is not based upon any compelling science. Further, such claims stem mostly from a single researcher who appears to spend most of her time spreading fear about EMF than producing quality research. The media and the public should not be confused by this lone researcher on the fringe into believing that “experts disagree.”

Rather, while there is always room for more research, there is already extensive evidence for the safety of non-ionizing radiation. Special cases, like long term (>15 year) use of cell phones, where the source of EMF is held right up to the skin, are still under investigation.

Exposure from EMF in the home, from light bulbs and other sources, pose no credible health risk. The media needs to do a better job of putting claims for health risks into the proper scientific perspective.

Posted in: Public Health, Science and Medicine

Leave a Comment (53) ↓

53 thoughts on “CFLs, Dirty Electricity and Bad Science

  1. windriven says:

    One tiny quibble-

    Dr. Novella said: “Further, there are CFLs available that are shielded and put out the least total UV light of all options.”

    Actually, it is arguable that of all options LED light bulbs produce the least UV radiation. Most LED light bulbs drop off at a wavelength of about 420nm. UVA ends and visible light begins at about 400nm. UVB wavelengths are even shorter.

    LEDs tend to emit in a relatively narrow bandwidth. White light is produced by either using a combination of blue, green and red emitters or by coating the emitters with a phosphor – much as CFLs do.

  2. windriven – you are correct, I was referring to the three types studies in the link provided – CFL, incandescent, and halogen. LEDs were not studied.

    Once they figure out the directional problem (LEDs tend to spew light in one direction rather than spread light in all directions) LEDs are the clear winner in every other category. They use the least electricity and last the longest. Price is still high, but with the energy and replacement savings they are still cost effective, and price will come down.

    Right now they are best for spot lighting, but still not optimal for room lighting. If good LED products hit the market, though, they are likely to quickly displace CFLs.

  3. “Exposure from EMF in the home, from light bulbs and other sources, pose no credible health risk.”

    I’m not sure if that is true. Exposure to this text…

    “Unfortunately, in popular summaries of the issue I often find that this exhaustive expert review of 25,000 studies is put up against – the opinions of Magda Havas – with the conclusion that “the experts disagree” therefore, who knows?”

    via my EMF emitting monitor cause me to slap my forehead, thereby disrupting my hot coffee onto my lap. EMF is now known to cause first degree burns. :)

  4. bartdeblog says:

    Coincidentally, I was reading about the CFLs just today, having found an article quack site claiming that the NWO is killing people off with melanoma caused by fluorescent lighting, quoting a 1982 study that showed a RR of over 2 for those working under fluorescent lamps. I googled a bit and… well, there were later studies that showed the effect and some that didn’t (no study showed a ratio as high as the original study). Still, it’s quite worrying, as we know the mechanism of UV radiation causing skin cancer.

    The initial study abstract is here:

    http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2882%2990270-7/abstract

    I was wondering, what is your take on this?

  5. From reading through pubmed, it seems the earliest studies were the most positive, then the results settled on a possible smaller effect. But bulb technology has changed since then and it is questionable if the results are still relevant.

  6. “Even after a couple of feet the [electromagnetic radiation (EMF)] put out by light bulbs falls from tiny by many orders of magnitude to negligible. The EMF intensity at a distance of inches (as shown in the Facebook video) is irrelevant.”

    By “EMF,” you mean light? The stuff that these devices are intended to generate? You’re saying that there is “negligible” (undetectable?) EMF two feet away from a lit lightbulb. In that case I guess that the whole discussion is moot, because if lightbulbs are incapable of illuminating anything then nobody’s using them.

    I am thinking that I’m missing something.

  7. daedalus2u says:

    There is an effect of co-exposure with infrared light, where photons of lower energy cause a de-excitation of molecules excited by a UV photon and exhibit a protective effect. Natural sunlight has photons like that, fluorescent lights don’t.

    Part of why fluorescent lights and LEDs are so efficient is that they produce light at wavelengths where human visual receptors are most sensitive. It takes fewer photons at the peak of sensitivity to detect an image with high resolution than when using photons at off peak. Colors are not quite the same as when viewed with broad spectrum sources.

  8. I am not sure about dirty electricity.

    I am much more alarmed about heavy electricity. It is like being hit by a ton of invisible lead soup.

    http://www.youtube.com/watch?v=IJCxJWwkHdQ

  9. kvanh says:

    The fluorescent lightst that flicker are the ones that use older ballasts. While new fixtures use electronic ballasts that don’t have the problem, many older buildings still have the old style (they started phasing them out in the early 90′s).

    The building i work in has the old style lights which give me headaches (not to mention the area i’m in is way over lit) i’ve had most of the bulbs in my area pulled to reduce the lighting level and get flickering lights out of my direct sight when working.

    I switched the majority of my lights at home to CFLs a couple of years ago and have no problems with them.

  10. Scott says:

    Right now they are best for spot lighting, but still not optimal for room lighting. If good LED products hit the market, though, they are likely to quickly displace CFLs.

    Personally I’d be happy with ANY LED products hitting the (local) market. In a Boston suburb, I can’t find any anywhere.

    Part of why fluorescent lights and LEDs are so efficient is that they produce light at wavelengths where human visual receptors are most sensitive.

    Yeah, that pesky black-body spectrum really kills incandescent efficiency. In order for them to peak in the wavelengths the human eye uses, they’d have to be the same temperature as the sun. (And anybody who thinks that’s coincidental, well, think about it a bit more.)

  11. xwolp says:

    I was wondering when Type 3 diabetes would make it on here.
    I think I suffer from Type 4 diabetes as it seems to worsen when I read about Type 3 diabetes.

  12. Calli Arcale says:

    I use CFLs in my house at every opportunity. That said, they do present substantial environmental and economic problems in the long term, though of course generally not the ones people get all hot and bothered about. (That’s the biggest irony of many environmental topics; pop culture ends up focusing on one which is either not so serious or even not actually real and ignoring actual, real problems.)

    The biggest problem with CFLs is probably disposal, though eventually materials for manufacturing will become a problem. The latter is also a concern for LEDs. Rarer elements are becoming more sought after and consequently more expensive, which in turn drives more exploration for new places to mine the stuff. Afghanistan has recently turned out to be particularly rich in some of these elements, which could become a blessing or a curse. There’s one of the big social and environmental problems — the race to exploit a reserve of rare metals can cause a lot of devastation if not done carefully. Disposal is another problem. CFLs are required to be recycled. In theory, this helps with the mining problem; if you can reclaim the metals, you can reduce the amount you need to mine. But in practice, recycling tends to be more expensive than mining (with some exceptions such as aluminum and steel), and the high labor costs and general NIMBYism at home mean there is a tendency to just ship the toxic waste abroad to countries which will either just dump it (due to a lack of oversight) or attempt to recycle by very hazardous methods.

    I think we do need to switch to more efficient bulbs, but we’ll also need to do something about the side effects at some point. This is not a problem specific to light bulbs, either; batteries are another biggie, as are electronic devices themselves. People seem to understand the value of recycling gold, aluminum, and copper from these devices, but propose building a plant to reclaim mercury or lead and you’ll have a citizen’s petition against you in no time. I can’t say I blame the NIMBYs, but these things will have to be built somewhere.

  13. bapowell says:

    I’m not a biologist or a medical researcher, but it seems to me that the sample size used in Dr. Havas’ study is probably too small to provide any statistically significant findings. That said, how reputable is the journal that Dr. Havas published in? I find it deeply troubling that there appears to be an official outlet for the findings of poorly designed studies.

  14. vicki says:

    I just want them to get rid of the old flickery fluorescents. I work by a combination of the overhead fluorescent lights (which sometimes flicker before they die, and then I hope someone listens to my complaints and replaces them quickly) and the light from my computer monitor. I cannot convince anyone to replace the defective, old-style fluorescent light built into my desk, which flickers very noticeably from the moment I turn it on until the moment I give up and turn it off, whether that’s three minutes or nine hours later. (Mine isn’t the only one that does this, but some of my coworkers are, happily, less bothered by the flickering.)

  15. moderation says:

    I thought I recognized the name:

    Professor Magda Havas of Trent University is currently the primary promoter of the idea that wi-fi in schools is causing an epidemic of illness in children. From your friends at Skeptic North:

    http://www.skepticnorth.com/2010/08/ontarioswifi-phobia-2/
    http://www.skepticnorth.com/2010/08/further-down-the-wifi-rabbit-hole-i-go/

    The CBC even did a very sensationalistic story with almost no counterweight to Professor Havas (she shows up at about 2 min 50 sec).

    http://www.cbc.ca/thenational/blog/2010/09/wi-fi-should-we-be-worried.html

  16. windriven says:

    “Right now they are best for spot lighting, but still not optimal for room lighting.”

    If you think about it the omnidirectional nature of incandescents and fluorescents isn’t optimal for room lighting either. Who needs or wants a spherical lights source? That is why we have lamp shades for reading lights and various reflectors and diffusers for ceiling lights. It may be that the transition to solid state lighting will result in ‘shaped’ lighting products that actually put light where it is wanted and needed.

  17. Fredeliot2 says:

    Where I am in Connecticut and probably in other places the power company will subsidize the replacement of old T12 tubes with magnetic ballasts with new T8′s with electronic ballasts. The net savings in electricity can be enough to get less than a 2 year payback. There is a Federal mandate to phase out the old T12 bulbs. Anyone who is suffering from flicker should let their employer know that replacement can save money. There are also LED replacements for fluorescent tubes, the cost is a bit high but I’m sure they will get better and cheaper.

  18. robbmcleod says:

    The correlation between skin cancer and working under fluorescent lighting is probably due to vitamin D deficiency (i.e. less daytime sun exposure) than the lighting itself, no? You would have to show a difference between people working under incandescents (unlikely given the expense) and fluorescents and people working outdoors to show that indoor lighting has a real impact here.

  19. Kawarthajon says:

    Steve,

    You’re dead right about Dr. Havas. She is a terrible crank (I can think of a lot worse words for her, but I’ll be civil). She lives in my community (Ontario) and she’s one of the driving forces behind the whole ban wireless internet from elementary school. Her research is a joke, but she’s seen by the Canadian media as some sort of expert. It boils my blood to think of the energy she’s putting into promoting her unscientific make-believe.

  20. Damned Skeptic says:

    Since fear mongering is a favorite past time for some environmentalists, it’s ironic that they are down playing the hazards of the mercury in CFLs. I imagine, without the fear of global warming apocalypse, instead of touting CFLs and getting the government to ban incandescent lights they’d have questioned the industry statistics on longevity and energy savings and warned of the dangers of bringing a toxic bulb into our homes. Plus, I’m sure there would have been at least one lawsuit stemming from the lack of adequate warning labels on the bulbs. Maybe there’s still hope that they’ll get to go after CFLs if LEDs or some bulb type proves to be a viable alternative.

  21. Joe says:

    @windrivenon 22 Sep 2010 at 1:16 pm wrote ” “Right now they are best for spot lighting, but still not optimal for room lighting.” “If you think about it the omnidirectional nature of incandescents and fluorescents isn’t optimal for room lighting either.”

    That is an interesting point. However, LEDs are really extreme in their “spot” capacity. Engineering can solve the problem- you can have LEDs installed at points over every few square inches of your living room ceiling so you can walk-around and be able to read ‘whatever’. As things stand economically, I can afford to see what is in the circle of light offered by an LED; but it has has limited utility to see anything more.

  22. ROTiree says:

    “Even if a bulb is broken the exposure to mercury is negligible, far less than eating a tuna fish sandwich.”

    OK, looking at the FDA website, “light canned tuna” (albacore?) has a mean concentration of methylmercury of 0.118 PPM, or 0.118mg per kg. So, 1.4mg of mercury is equivalent to eating 11.86 kg of tuna. Big sandwich, there…

    The FDA website also says that 6 oz of tuna is the recommended weekly intake for pregnant women, nursing mothers, children, etc, still giving us a pretty large sandwich and only 0.02mg of methylmercury.

    Mercury absorption through intact skin is very low and even swallowing liquid mercury means you absorb only 1% of what you would if you inhaled an equal mass in vapour form. Cut yourself as you pick up the broken pieces and it’s a different story. Eating fish contaminated with organic mercury compounds (methylmercury) gives the same absorption rate as for vapour (almost complete for both cases).

    Granted, you’d have to be terminally insane to sniff a broken CFL tube, but if you inhale just 1.4% of that vapour, not unreasonable, perhaps, if someone bends down to clean it up straight after it broke, then no tuna sandwiches for a week.

    Not quite so insignificant any more…

  23. nitpicking says:

    ROTiree, you’re equating metallic mercury with methylmercury. I don’t think you can do that–organic mercury is enormously more toxic IIRC.

  24. moderation says:

    @ ROTiree

    Nice math but you missed a few steps. As was said, the mercury in the bulb is not organic and only a very small percentage vaporizes at room temperature. So… unless you are going to carefully break the bulb open and lick out the mercury contain there in, you are will consume more mercury in a tuna sandwich than you will absorb through your skin or inhale in the form of vapors from a broken CFC bulb.

  25. ROTiree says:

    @ nitpicking – methylmercury is more toxic than metallic, yes. Dimethylmercury is even worse.

    Still going to mess you up, though. There was one case where a toddler played in a room containing a box with 8 broken fluorescent tubes in it. He showed symptoms of mercury poisoning over a period of days.

  26. grayehound says:

    I stumbled across that YouTube video earlier this week and researched it. I came across the same info and sent the links to Brian Dunning to suggest a possible Skeptoid episode, but I’m thrilled you addressed this bull so thoroughly. Nicely done, Doc!

  27. nybgrus says:

    @ robbmcleod: As far as I know, vitamin D and melanoma do not have a correlation. Vitamin D is vital for calcium absorption and lack of sun exposure can lead to rickets in children or osteomalacia in adults. In Australia, because they have become so conscious of the UV levels and have VERY effective campaigns for sun protection those are actually becoming noticed effects. I would reckon though, that your proposed mechanism is not so likely – unless someone else has some info I am missing?

    @ROTiree: good on ya mate! As I was reading the article I was thinking the same thing myself, since I just a few weeks ago did that same exact research. Very good points you make, though I think we can all agree that in most common circumstances, Hg exposure would be quite limited from a broken CFL.

    I tend to agree with the general ideas presented here, especially the notion that Havas is a crank and “dirty electricity” makes little sense to me. However, I have sent this on to my girlfriend who is a mechanical engineer with experience in greenspacing and a lot of experience specifically with CFLs so I will be curious as to her take.

  28. Jurjen S. says:

    ROTiree wrote:

    So, 1.4mg of mercury is equivalent to eating 11.86 kg of tuna. Big sandwich, there…

    Yeah, if you ingested the entire CFL. Though if you did, mercury poisoning would presumably be pretty far down your list of health concerns.

    Granted, you’d have to be terminally insane to sniff a broken CFL tube, but if you inhale just 1.4% of that vapour, not unreasonable, perhaps, if someone bends down to clean it up straight after it broke, then no tuna sandwiches for a week.

    Assuming 100% of the mercury in the CFL were released as vapor. And honestly, how much a hardship is it to do without tuna for a week? (And I should point out I love tuna.)

  29. urg, I find it hard to keep track of the fish that have more mercury or less (tuna, whitefish yes, Alaskan wild caught salmon, no, that’s all I remember).

    But I will say that even with two rambunctious kids in the house we’ve only broken one CFL since we had them (the kids…the CFLs came first.) And it was pretty easy to clear everyone out to wait a few minutes before clean up. It always best to clear out the kids when cleaning up glass regardless.

    I actually have a lot of things in the house that are dangerous if you refuse to engage your brain before use or during maintenance. To me, the CFLs seem like a good risk/benefit investment.

  30. SD says:

    @daedalus2u:

    “There is an effect of co-exposure with infrared light, where photons of lower energy cause a de-excitation of molecules excited by a UV photon and exhibit a protective effect. Natural sunlight has photons like that, fluorescent lights don’t. ”

    Uh, okay, since you’re always on about nitric oxide as the One True Life-Molecule and Fuel of Cosmic Timecubeness, I shouldn’t be surprised, but… um, *no*.

    I will be charitable and suggest that you go pick up a book on physical chemistry, then flip to the sections about spectroscopy and quantum electronics. Citation Needed, my son. Absorbing a photon makes energy levels go *up*, not *down*, unless otherwise indicated.

    Regarding mercury in the lamps… well, yeah, I could believe that. That depends on when and if the lamp breaks. If it broke while you had it on, or shortly before you turned it on – yeah, this happened to me once – then your mercury exposure could be unsafe, I imagine. I recall reading of a gentleman, once upon a time, who attempted to enrich himself by cooking gold dental fillings in a pan on his stove to extract the gold – trouble was, it extracted the mercury instead, turning his small apartment into a gas chamber. The story related his gruesome death by pneumonia after a two-day illness, during which he got to experience the joys of severe brain damage. (The story doesn’t relate whether the brain damage occurred before or after the mercury poisoning, but suggested that it might have occurred as a result of the poisoning rather than as a cause. I’m still on the fence about that.)

    Still, mercury isn’t quite the insta-death toxin it’s made out to be; hell, people used to *drink* it. Depends on the person. Some people tolerate mercury OK; some people don’t, and die of the exposure. RIP Karen Wetterhahn, for instance.

    All of the other complaints are hogwash, though. Teh 33333vul electromagnetisms might nukulurize you! AND STUF! Yeah, forget about all the crusty old hams operating multi-kilowatt gear that emits RF at the same frequency. And, ignore the “non-ionizing” nature of the radiation, well-established by various experiments by physicists and chemists, risking life and limb by working around DANGEROUS NUKULUR STUF, to determine that an RF photon doesn’t do squat to an electron, owing to a lack of energy… Forget all that. Yeah, and the white stuff on the inside of the bulbs – you know, the stuff that glows? Yeah, that’s the UV shielding. In fact, that’s where a lot of the visible light comes from – fluorescence (i.e. UV absorption). (Try this experiment: turn on a CFL lightbulb in a dark room, then squeeze your eyes shut and wait for your night vision to return. With your eyes closed, turn off the bulb, then open your eyes. See that green glow? Yeah, that’s the persistent fluorescence of the phosphor used in the bulb dying out.)

    One problem with CFLs is those electronic ballasts – they’re not perceptibly bad for health or vision, but they will have a seizure and die horribly if they’re fed bad power (surges/spikes), particularly if they’re made with low-quality components. When that happens, you’re out an expensive bulb. Lesson: buy a surge protector and put your CFLs on that. Lesson #2: do not use them on a dimmer circuit unless they were specifically designed for that use (most are not), unless you like the idea of buying new bulbs and possibly a new dimmer.

    “fiat lux”
    -SD

  31. Here is more info on mercury exposure after breaking a CFL:

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2535642/

    Some points – about 1/3 of the mercury is released as vapor over a period of 4 days. Significant exposure would only occur if the bulb were left in a poorly ventilated room for days. (The amount of mercury released is also less for used bulbs.)

    If you clean up the break and ventilate the room, exposure should be insignificant.

    (added reference to original article)

  32. squirrelelite says:

    Dr Novella,

    Off topic, but is there a problem with the web site for the Neurologica blog?

    I haven’t been able to get through to it for several days and I saw someone else mention it on another comment thread.

  33. Yeah – we are having CPU usage problems. We have been troubleshooting it, and making progress, but still not there yet. Hopefully we will be back up soon.

  34. Adam says:

    Thanks for posting this. I run a small local group and we had just been asked about this claim.

  35. Epinephrine says:

    I’m surprised that LED products aren’t available for Scott (above) – I’m in Ottawa (Canada) which isn’t as big a city as Boston. We have several LED bulbs (6 or so?) in our house, with newer more effective ones being introduced as they become available. I’m making the switch gradually because of the price of the bulbs, and of course because the technology is still improving, but the little 1.5 Watt LED bulbs are great for reading lights. Originally I only had multi-LED (20+ diode) bulbs, but now the Sylvania bulbs with 1 or 3 LEDs are available, and they are pretty nice for directional lighting.

    Canadian Tire and Home Hardware both carry LED bulbs (for those in Canada), but I’m sure there must be an equivalent store in the USA.

    Some above mentioned spectrum issues; I haven’t surveyed the literature that much, but I recall some work on light therapy for seasonal affective disorder, and have read that blue light may be responsible for much of this effect. I will admit to some curiosity about the role that blue light may play in circadian rhythms and SAD, and whether the spectra of fluorescent lighting (typically weak in the blue wavelengths) may be contributing. Not that LED bulbs are necessarily any better, i haven’t looked at the spectra for them, though I know that blue wavelength LEDs exist, so one could easily build LED bulbs with stronger blue-wavelength spectra.

  36. Epinephrine says:

    Oh, and before someone points out that Ottawa itself is comparable to Boston in size, the metropolitan area of Boston is much larger than the equivalent Ottawa-Gatineau metropolitan area. :P

  37. Calli Arcale says:

    Epinephrine — LED bulbs are starting to show up in the US too. I’ve seen them at Home Depot and at Menards, which are a couple of large hardware store chains.

  38. JMB says:

    Exposure from EMF in the home, from light bulbs and other sources, pose no credible health risk.

    Agreed, but just to nitpick, don’t stick your head in the microwave oven and turn it on.

  39. Damned Skeptic says:

    micheleinmichigan may be an exception, but I doubt most of us have the dedication it would take to do a real risk/benefit analysis on CFLs. Acceptable personal risk is subjective, but for those of us that bought poorly manufactured bulbs from a well known members only warehouse store it was a clear loss since many of the bulbs burned out quickly, sometimes cracking in the process. We fell for the hype and got burned. If there is a next time for CFLs, I’m going to make sure they come with a warranty and save the receipt.

    I just came across this web page (http://www.green-energy-efficient-homes.com/cfl-savings-calculator.html) which allows you to change the inputs and calculate CFL savings. Keeping in mind that it doesn’t adjust for extra heat needed on cool days, it will give you a straight watt to watt comparison assuming that it’s accurate. There’s also an LED calculator which I used to compare CFL to LED since incandescent bulbs may be on their way out. Using the prices given the break even point for LED when compared to CFL is 22 years, so if you don’t want CFLs it’d probably be a good idea to stock up on incandescent bulbs unless the law is repealed or a not expensive energy efficient incandescent bulb is developed.

  40. daedalus2u says:

    SD, there is stimulated emission, where an excited state is caused to emit its energy via the stimulation of a photon, as in Light Amplification by Stimulated Emission of Radiation.

    Florescence is an example of this too. There are IR detectors that one can “charge up” which then emit visible light when irradiated with IR.

    The same thing does happen with DNA and other molecules. The UV photon is absorbed, generating an excited state, but that state doesn’t decay immediately via a molecule breaking path. An IR photon can accelerate the relaxation of that excited state via a path that does not break molecular bonds.

    Too much IR is not good and there are other effects too, not related to DNA

    http://www.nature.com/jid/journal/v129/n5/full/jid2008362a.html

    I remember reading something where they showed that simultaneous UV and IR was less damaging than the same UV dose alone, and that this was the explanation for why you could get such a bad sunburn on a cloudy day, the clouds blocked the IR but only scattered the UV. .

  41. nybgrus says:

    In skimming through the article that seems quite interesting. However, the mechanism they describe is that the IR light up-regulates the expression of anti-apoptotic proteins and DNA repair mechanisms as well as tumor suppressor genes. This does not indicate the the IR photon helps to mitigate the damage by UV light via some alternate de-excitation pathway but instead by upregulating the repair mechanisms for damage already done by UV light.

    So yes, there is a protective effect, but not via a direct excitation-deexcitation mechanism.

  42. gdjsky01 says:

    Couldn’t pass up an article on SBM about lighting without:
    One of the best ways to save energy and be green is to turn off outdoor lighting. (And as a side effect, give me back the night sky I love.)

  43. overshoot says:

    One more nit: the flicker rate from fluorescents isn’t 60 Hz, it’s 120. The bulb lights on each half-cycle of the line.

  44. daedalus2u says:

    I can’t seem to find a reference to it. It may have been something I read a long time ago and it was speculation that the protective effect of IR was due to de-exciting DNA excitations.

    Photoinduced thermoluminescence of irradiated minerals is well known and is the basis for a lot of dosimetry, x-ray and UV.

  45. Charlie says:

    Thanks for this timely post.

    Last night I was watching a TiVo’d episode of MythBusters while my wife was checking out her Facebook site when I began to hear fragments of an online video from her laptop. Based on the little I could hear of what she was listening to my BS alarm was triggered. Yes, she was listening to the video you referred to in your post. When I “suggested” that the video was nonsense, she replied “But she’s a doctor.”

    A quick Google search brought me to your post and we were able to quickly dispense with the foolishness. As a regular listener to the SGU and reader of your NeuroLogica blog I think it is very cool that my search for reason took me directly to this site.

    Thanks again.

  46. Damned Skeptic says:

    Since reading this blog post my thoughts keep returning to CFLs, so I reread it this morning. I’m now more concerned about CFLs than I was before, and I think Mr. Novella was wrong to state that “…the small amount of mercury [in] CFLs is not a health or environmental risk…” .

    According to the “EPA study” linked to in the blog “…the team recorded mercury gas concentrations near the bulb shards between 200–800 μg/m3. For comparison, the average 8-hour occupational exposure limit allowed by the Occupational Safety and Health Administration is 100 μg/m3.” And the head of the research group, Robert Hunt, is quoted as saying, “The amount of mercury gas coming off [broken CFLs] is over a milligram over a few days. If you put that milligram into a poorly ventilated room, the concentration can be over the recommended limit for children [of 0.2 μg/m3],” says Hurt. “The overall risk is low, but it’s not zero risk, and there is definitely an opportunity to do better.”

    We need to recognize that there are health and environmental risks associated with CFLs and take the proper precautions when handling, storing and disposing of broken bulbs. Pretending otherwise leads to a lack of caution like at my local Home Depot which just has a can for people to drop their used CFLs into for recycling. I’d bet that is not the recommended method.

  47. SouthernFriedScientist says:

    We ran the math on mercury exposure from CFL’s versus incandescents. Executive summary – even under the most conservative estimates (50% power from coal, everyone smashes their CFL’s with glee, 4 mg Hg per CFL), mercury released into the environment from powering incandescent bulbs is still greater than mercury from CFL’s.

    http://www.southernfriedscience.com/?p=7861

  48. nukenorth says:

    Just for completeness, it turns out that many CFLs include a radionuclide to assist with fast turn-on. See “NEMA LSD 15-1993 (R-2001)”. All the CFLs I’ve tested provide a count rate when placed on a sensitive Geiger detector similar to what I’ve observed with ionization smoke detectors, doubling the background count rate. It’s no big deal unless you have a phobia.

    Neither LED lamps nor CFLs are going to replace the incandescent light bulb in your oven anytime soon. The electronics can’t take the heat.

    More serious hazards arise from misapplication. The instructions recommend handling by the base, not the glass spiral — making them unsuited for recessed lighting fixtures unless they have an additional cover. A hand full of a broken CFL is not a good idea. Moreover, they are not to be used in totally enclosed fixtures as the captured heat may cause the electronics to fail.

    Lastly, CFLs (at least in North America) have “low power factors” (sorry, it’s an electrical engineering thing). The current and voltage waveforms have a significant phase difference. Again, it’s no big deal in the average home. It may matter if you’re off-grid using batteries and an inverter.

  49. evilrobotxoxo says:

    @daedalus:

    I’m skeptical that the mechanism of IR protection is by a direct de-excitation pathway because I doubt that the “concentration” of IR photons is high enough under ambient lighting conditions that a high percentage of excited molecules would absorb one during the short lifetime of its excited state. This is the basis of how two-photon microscopy works, for example, that these multiphoton events only occur under conditions of incredibly intense illumination, i.e. at the diffraction-limited focal spot of a high power femtosecond pulse laser. I’m not saying it’s impossible that this can happen under ambient sunlight, only that it strikes me as unlikely.

  50. VaporLok says:

    CFLs are a better solution, both economically and environmentally, than incandescent bulbs, which ultimately result in greater mercury exposure than CFLs, because they consume more power and require more power generation. Since mercury is a byproduct of burning coal, coal-fired power plants are a larger source of mercury pollution than the mercury content in the CFLs. Although CFLs do contain a small amount of mercury, with a proven packaging configuration and proper disposal, CFLs can be used effectively without releasing harmful mercury vapor.

    While a variety of containers are marketed for transportation of fluorescent lamps and CFLs, many don’t provide sufficient protection against mercury vapor emitted from broken lamps. Using a proven packaging design is vital to ensuring the safety of people who handle these lamps, as well as maintaining their green benefits. Read about a recent study that tested several packaging configurations at vaporlok.blogspot.com/2010/05/layers-of-protection-packaging-used.html

  51. daedalus2u says:

    evilrobotox, There are relatively larger numbers of IR photons than UV photons, and on DNA the excitation energy is not localized but spreads out and propagates along it (in solution, how that works in cells with the DNA wound up on histones is more complicated and I don’t really know). In multi-photon fluorescence the excitation energy is localized on the fluorescent molecule being used.

    The mechanism I suggested (IR de-excitation of UV excited DNA) may not be real, but there are other mechanisms involving protective effects of IR that are real, and because fluorescent lights don’t produce as much IR, there may be adverse effects from the lack of IR compared to incandescents and flames. There are IR induced fluorescence from excited states excited by higher energy photons in inorganic systems.

    Any IR effects are probably second order. But doing studies of the effects of light on things like DNA damage is difficult because some of the effects are multi-photon and so are extremely sensitive to the instantaneous flux of photons and their wavelengths. LEDs because they are a single wavelength might behave differently than light sources with a broader spectrum. Pulsed LED sources can have fluxes many orders of magnitude higher than continuous wave fluxes. Fluxes high enough that multi-photon effects are possible.

    There was some discussion of a “magic light helmet” to treat Alzheimer’s using pulsed IR LEDs. I discuss the mechanism for that on my blog. I think it is photodesorption of NO from cytochrome c oxidase and temporary reduction of superoxide from mitochondria. I think the “magic light helmet” is potentially a very dangerous way of trying to affect Alzheimer’s symptoms and could lead to making it worse.

    http://daedalus2u.blogspot.com/2008/06/more-on-magic-light-helmet-for.html

    I think that designers of LED lighting systems should design them to not used high amplitude short duration pulses, or if they do they should limit peak flux to something reasonable and something that is not too non-physiologic. Peak energy fluxes of kW/m2 are on the order of sunlight. MW or GW/m2 are not. Large peak fluxes of very short duration may cause adverse effects (that they do not is unknown).

  52. evilrobotxoxo says:

    daedalus,

    Re: IR protection during UV exposure — my only point is that it strikes me as profoundly implausible that IR de-excitation is the dominant mechanism underlying that effect.

    As far as the magic light helmet, it is essentially impossible that there is significant multiphoton excitation in endogenous chromophores going on at the intensities obtainable by a helmet full of NIR LEDs, which can’t even be focused to a diffraction-limited spot. I spent a lot of time building and modifying two photon microscopes in the early days before they were commercially available, and tragically, multiphoton excitation just can’t be obtained that easily or cheaply.

    As far as UV emission by indoor lighting sources goes, it’s all kind of moot because passive shielding is trivial to implement.

  53. paragshah says:

    CFLs are a better solution than incandescent bulbs, which ultimately result in greater mercury exposure than CFLs, because they consume more power and require more power generation. Since mercury is a byproduct of burning coal, coal-fired power plants are a larger source of mercury pollution than the mercury content in the CFLs. With a proven packaging configuration and proper disposal, CFLs can be used effectively without releasing harmful mercury vapor.

    While a variety of containers are marketed for transportation of fluorescent lamps and CFLs, many don’t provide sufficient protection against mercury vapor emitted from broken lamps. Using a proven packaging design is vital to ensuring the safety of people who handle these lamps, as well as maintaining their green benefits.
    How to recycle CFL bulbs

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