LED Streetlights Are Giving Neighborhoods the Blues - IEEE Spectrum Magazine article

[gary]

In a 22nd Sept article (http://spectrum.ieee.org/green-tech/conservation/led-streetlights-are-giving-neighborhoods-the-blues)in the Institute of Electrical and Electronics Engineers
(IEEE) Spectrum magazine, Jeff Hecht writes on how some early adopters
of LED street lighting are struggling with glare and light pollution.







Article here -
http://spectrum.ieee.org/green-tech/conservation/led-streetlights-are-giving-neighborhoods-the-blues

[multiweb]

We got all LED in Hoxton Park now. The new lights have focusing lenses that narrow the beam down and are countersunk in the casing of the lamp head. I wasn't too sure what to expect before they've installed them but since then I've noted a very significant drop in LP locally so I'd say it's better than the older system. The light is right across my bedroom window on the second floor and I hardly notice it now. The old bulb was much thicker and lighting up sideways the whole side of the house was lit.

[StuTodd]

These LEDs have a lot of blue light in them, very bad for health/wildlife etc. Make sure no light is getting into your bedroom...

[multiweb]

I doubt it makes it through a brick wall.

[sharkbite]

This article states



this is roughly the same colour temp as the sun....(certainly not any more "Blue")

how is this bad for ones health?

[StuTodd]

No. Colour temperature in lighting represents the apparent look of say, a bar of iron when heated to the stated temperature. For example, heat an iron bar to between 2-3000° Kelvin and you get an orange glow (ironically called "warm white", 3-4500° K the bar gets whiter, and then 5000K upwards, the bar will get white hot (LEDs, TV and computer screens etc).

The reason there is worldwide movement to get governments and councils to rethink replacing their aging HPS lighting the 5000K LED lights is that such light contains a lot of blue.
Now blue light (like that in sunlight) is good for us in daylight but when it comes to night time, exposure to blue is known to disrupt our circadian rhythms, suppress melatonin production and confuse nesting and breeding wildlife (birds, turtles etc etc).
The rub is that exposure to blue light during the night has been linked to increase in depression, certain types of cancer and diabetes.

Here in Dunedin, the Dark Skies Dunedin group (N1 is involved along with RASNZ and other experts in the field) managed to persuade the council to stop the wholesale swapping of our old HPS with the LEDs and form a committee, reporting to the council, on the harm/benefits of different types of LED.

Have a look at http://www.flagstaffdarkskies.org/led-lighting-dark-skies/ for more info on the pollution aspect of LEDs.

Stu

[AussieTrooper]

Because it's at night. Take a photo of a white sheet of paper at noon. Do the same at dusk. It will be redder. We are adapted to associate falling and reddening light with night and sleep.
Bright bluish light is the absolute opposite of this.
I'm surprised that it's even legal to have these as car headlights, given how dazzling they are.