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    The Dangers Of White LED Bulbs
    By News Staff | September 12th 2011 10:03 AM | 3 comments | Print | E-mail | Track Comments

    With a ban on incandescent bulbs looming in the US, the race is on to try and replace them - unfortunately the ban was used to artificially force innovation, which isn't how things work in science and technology, and CFL bulbs have mercury risk while concerns linger about LEDs and melatonin. 

    Melatonin is a compound that adjusts our biological clock and is known for its anti-oxidant and anti-cancerous properties.   "White" light bulbs that emit light at shorter wavelengths are greater suppressors of the body's production of melatonin than bulbs emitting orange-yellow light, a new international study has revealed. Exposure to the light of white LED bulbs, it turns out, suppresses melatonin 5 times more than exposure to the light of High Pressure Sodium bulbs that give off an orange-yellow light. "Just as there are regulations and standards for 'classic' pollutants, there should also be regulations and rules for the pollution stemming from artificial light at night," says Prof. Abraham Haim of the University of Haifa.

    The study investigated the influence of different types of bulbs on "light pollution" and the suppression of melatonin, with the researchers recommending several steps that should be taken to balance the need to save energy and protecting public health.

    "Just as there are regulations and standards for 'classic' pollutants, there should also be regulations and rules for pollution stemming from artificial light at night," says Prof. Abraham Haim, head of the Center for Interdisciplinary Chronobiological Research at the University of Haifa and the Israeli partner in the research.

    The fact that "white" artificial light (which is actually blue light on the spectrum, emitted at wavelengths of between 440-500 nanometers) suppresses the production of melatonin in the brain's pineal gland is already known. Also known is the fact that suppressing the production of melatonin, which is responsible, among other things, for the regulation of our biological clock, causes behavior disruptions and health problems. 

    In this study, conducted by astronomers, physicists and biologists from ISTIL- Light Pollution Science and Technology Institute in Italy, the National Geophysical Data Center in Boulder, Colorado, and the University of Haifa, researchers for the first time examined the differences in melatonin suppression in a various types of light bulbs, primarily those used for outdoor illumination, such as streetlights, road lighting, mall lighting and the like.

    In the first, analytical part of the study, the researchers, relying on various data, calculated the wavelength and energy output of bulbs that are generally used for outdoor lighting. Next, they compared that information with existing research regarding melatonin suppression to determine the melatonin suppression level of each bulb type.

    Taking into account the necessity for artificial lighting in cities, as well as the importance of energy-saving bulbs, the research team took as a reference point the level of melatonin suppression by a high-pressure sodium (HPS) bulb, a bulb that gives off orange-yellow light and is often used for street and road lighting, and compared the data from the other bulbs to that one.

    From this comparison it emerged that the metal halide bulb, which gives off a white light and is used for stadium lighting, among other uses, suppresses melatonin at a rate more than 3 times greater than the HPS bulb, while the light-emitting diode (LED) bulb, which also gives off a white light, suppresses melatonin at a rate more than 5 times higher than the HPS bulb.

    "The current migration from the now widely used sodium lamps to white lamps will increase melatonin suppression in humans and animals," the researchers say.

    The researchers make some concrete suggestions that could alter the situation without throwing our world into total darkness, but first and foremost, they assert that it is necessary to understand that artificial light creates "light pollution" that ought to be addressed in the realms of regulation and legislation.

    Their first suggestion of course, is to limit the use of "white" light to those instances where it is absolutely necessary. Another suggestion is to adjust lampposts so that their light is not directed beyond the horizon, which would significantly reduce light pollution. They also advise against "over-lighting", using only the amount of light needed for a task, and, of course, to simply turn off lighting when not in use - "Just like we all turn off the light when we leave the room. This is the first and primary way to save energy," the researchers say.

    "Most Italian regions have legislations to lower the impact of light pollution, but they still lack a regulation on the spectrum emitted by lamps. Unless legislation is updated soon, with the current trend toward sources as white LEDs, which emit a huge amount of blue light, we will enter a period of elevated negative effects of light at night on human health and environment. Lamp manufacturers cannot claim that they don't know about the consequences of artificial light at night," says Dr. Fabio Falchi of ISTIL.

    "As a first step in Israel, for example, the Standards Institution of Israel should obligate bulb importers to state clearly on their packaging what wavelengths are produced by each bulb. If wavelength indeed influences melatonin production, this is information that needs to be brought to the public's attention, so consumers can decide whether to buy this lighting or not," Prof. Haim says.

    The study "Limiting the impact of light pollution on human health, environment and stellar visibility" by Fabio Falchi, Pierantonio Cinzano, Christopher D. Elvidge, David M. Keith and Abraham Haim, is published in Journal of Environmental Management.

    Comments

    There is a serious mistatement in this article. What the research shows that there is 5 times more blue light - so called melatonin suppressing band - produced by some low efficiency white LED than a HPS lamp light, NOT that it causes a 5X reduction in melatonin in individuals exposed to this light. If one follows this argument to its conclusion, typical exposure to sunlight must completely supress melatonin production and we should all be melatonin free - not. Unfortunately, most studies on melatonin supression consist of exposing subjects to very bright light during late night and in many cases normal sleeping time (i.e. wake up the subject and expose them to bright light, in some cases applying a pupil dialator, often using young males who typically are still awake after midnight). This says nothing about exposure to typical levels of light at typical times of exposure. What some of these studies do show is that exposure to low light levels produce no measurable effect. In one ridiculous study, subjects were exposed in the middle of the night to 500 lux for 30 minutes which is more than an order of magnitude brighter than the brightest street lighting and equivalent to bright task lighting. All that can be said for sure is don't get up in the middle of the night and stand under a spotlight for 1/2 an hour with your eyes wide open. How about studying the melatonin levels in residents of cities with HPS streetlights compared to those in cities with metal halid street lights? Next we'll hear that putting a 50 Kg weight on your chest will impair respiration so avoid sleeping under heavy blankets.

    Dear GeorgeR

    Sunlight does indeed suppress the production of melatonin completely - which is just fine in the daytime.

    The problem is that we need to allow melatonin to be produced during the night - to signal darkness and prepare us to sleep, and to facilitate various repair processes. Blue enriched lights (which most white leds are) at modest brightness levels do indeed impair the production of melatonin.

    Look up Dieter Kunz for one study. Or google
    Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us
    Alert?
    in which 40lx 6500K halved melatonin in comparison to 40lx 2700K.
    There is even a study about computer screens, like you are presumably using right now, which alse significantly alter melatonin levels (Cajochen etc)

    So it is indeed somwhere between plausible and probable that it's a problem.

    Steve

    As for people working at night,

    Pale grey typeface on a white background makes for very hard reading for anyone with poor eyesight. Have you never wondered why books are printed in BLACK and white?