Dangers of exposure to “white” light

[OKIsItJustMe]

http://newmedia-eng.haifa.ac.il/?p=5516

Dangers of exposure to “white” light

Published by Editor at 10:21 am

“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.

…

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 Polution 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.

…

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.

…

http://dx.doi.org/10.1016/j.jenvman.2011.06.029

[DesertFlower]

1. interesting article. thanks for posting it.

[OKIsItJustMe]

2. You’re welcome

Things seem always to be more complex than we imagine them to be. “Hey, a light’s a light!” (Right?)

[KT2000]

3. Good book

on the subject. Great Sleep! Reduced Cancer!, Richard Hansler Ph.D.

Hansler worked his entire career designing light bulbs for GE. He later started designing light boxes for a doctor who was treating depression (SAD). Then, Hansler came upon all the research that taught him that the blue light was interrupting melatonin production - which eventually makes us more vulnerable to cancer.

[hunter]

4. If televisions weren't so rich in blue light...

... people would fall asleep before the eleven o'clock news.

And that would be a good thing.

[madokie]

5. I sense something awry here

Led's can be made to put out any color of light. In fact the manufacturers had to work at it to make them have a while light.

[OKIsItJustMe]

7. LED’s really can’t put out “any color of light.”

And “white LED’s” really aren’t white.

(Moderators, please note, US Department of Energy publication, i.e. copyright concerns are nil.)

http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/color_quality_of_white_leds.pdf

Color Quality of White LEDs

Color quality has been one of the key challenges facing white light-emitting diodes (LEDs) as a general light source. This fact sheet reviews the basics regarding light and color and summarizes the most important color issues related to white light LEDs, including recent advances.

Unlike incandescent and fluorescent lamps, LEDs are not inherently white light sources. Instead, LEDs emit light in a very narrow range of wavelengths in the visible spectrum, resulting in nearly monochromatic light. This is why LEDs are so efficient for colored light applications such as traffic lights and exit signs. However, to be used as a general light source, white light is needed. The potential of LED technology to produce high-quality white light with unprecedented energy efficiency is the impetus for the intense level of research and development currently being supported by the U.S. Department of Energy.

White Light from LEDs

White light can be achieved with LEDs in two main ways: 1) phosphor conversion, in which a blue or near-ultraviolet (UV) chip is coated with phosphor(s) to emit white light; and 2) RGB systems, in which light from multiple monochromatic LEDs (red, green, and blue) is mixed, resulting in white light.

The phosphor conversion approach is most commonly based on a blue LED. When combined with a yellow phosphor (usually cerium-doped yttrium aluminum garnet or YAG:Ce), the light will appear white to the human eye. Research continues to improve the efficiency and color quality of phosphor conversion.

The RGB approach produces white light by mixing the three primary colors - red, green, and blue. The color quality of the resulting light can be enhanced by the addition of amber to “fill in” the yellow region of the spectrum. Status, benefits, and trade-offs of each approach are explored on page 2.

…

[madokie]

9. True,

They can be made in several colors but not all colors. my bad.
http://donklipstein.com/ledc.html

ETA: I intended this to be a reply to #7 not to myself. sorry

[Javaman]

6. Here's a novel idea...

go outside!

[NYC_SKP]

8. Is it the exposure to White or the absense of warm colors?

Title seems to suggest that exposure to white is the bad guy while the body of information seems to suggest that it's the absence of a more full spectrum that is to blame.

Can't beat daylight.

Good read, K/R