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Arthur T Knackerbracket has found the following story:
[...] Councils and local governments from Paris to Brooklyn have replaced high-energy sodium bulbs (the warmer, yellow ones) with energy-saving LED bulbs (with a blue light emitting diode, which can feel harsh in comparison). As well as street lights, most of us are exposed to blue light through smartphones, computers, TVs, and in the home.
Earlier this year, the World Journal of Biological Psychiatry published a paper by a group of prominent psychiatrists that warned of the potential effects of LED lighting on mental illness.
It raised concerns about the influence of blue light on sleep, other circadian-mediated symptoms, use of digital healthcare apps and devices, and the higher sensitivity of teenagers to blue light.
[...] Studies of the impact of blue light on healthy adults show it inhibits melatonin secretion which disrupts sleep and can affect quality of life, physical and mental health and susceptibility to illness. Previous studies of sleep disorders in children and adolescents show a clear and consistent relationship between sleep disorders and frequency of digital device usage.
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(Score: 5, Informative) by isostatic on Tuesday July 17 2018, @07:46AM (4 children)
Saw a great video on street lights at https://www.youtube.com/watch?v=wIC-iGDTU40 [youtube.com]
One takeaway was that while 3K LED lights are worse for REM sleep than Sodium for a given power, they require less output for the same safety benefits, which reduces Melantropic light back to the level from normal sodium lights. At least for low temperature lights, however high temperature LED lights use less power per lumen so tend to be chosen (cheaper running costs).
(Score: 0) by Anonymous Coward on Tuesday July 17 2018, @01:15PM (3 children)
There are two kinds of sodium lights: high-pressure (broad spectrum, look orange to me) and low-pressure (narrow-band yellow). LEDs aren't inherently wide-spectrum. Monochromatic LEDs exist in various colors. An LED lamp that doesn't emit blue is easily achievable and potentially more efficient than the white lamps, because it needn't use a phosphor.
My city is expanding its surveillance apparatus by putting cameras at street intersections. Accompanying them are new white LED lamps that supplement the existing high-pressure sodium lamps. I surmise that the lights were selected to provide accurate color rendering for the surveillance videos.
(Score: 2) by bob_super on Tuesday July 17 2018, @05:15PM (2 children)
Sodium lamps save power and astronomers' sanities, but People Worried For Their Stuff have always complained that they are letting Bad People sneak around. Which was a decent tradeoff, until the LEDs brought low-power, allowing the security at the expense of people who like to see stars overhead (astronomers have mostly moved away, but the Palomar people are not happy about San Diego costing them one full stop). And sleep cycles.
Dumb question: LEDs can do any color, and red is the best for preserving night-vision and sleep. Any reason not to have the whole city be a bright-red light district ?
(Score: 0) by Anonymous Coward on Wednesday July 18 2018, @02:11AM (1 child)
The human eye has two types of cells, rods and cones. Rods are more sensitive to light in general, but are lower resolution and color blind and are found around the outside of your retina; cones are less sensitive, higher resolution, can see color and found near the center of the eye. The reason why red preserves night vision is because rod cells are completely insensitive to red wavelengths, and therefore don't reduce in sensitivity when in red light. The reason why you can't do what you want is because your overall vision is impaired because of the way you see red light. See, https://light-measurement.com/spectral-sensitivity-of-eye/ [light-measurement.com] for details. Also good is https://www.youtube.com/watch?v=wIC-iGDTU40 [youtube.com] for a thorough, if not long-winded, explanation of various pros and cons.
(Score: 1) by schusselig on Wednesday July 18 2018, @04:45AM
False. It's actually because of this [soylentnews.org]