
Doctors issue warning about effects of LED streetlights on health - cauterized
https://theconversation.com/american-medical-association-warns-of-health-and-safety-problems-from-white-led-streetlights-61191
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brenschluss
Title is misleading; it's not LED streetlights, it's the _color temperature_
of LED streetlights. While the article raises a few good points, color
temperature isn't new; it's not like LEDs have some inherent issue that
impacts health.

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stormbeta
True, but there's a real problem with people and places using lights with
_far_ too high a temperature, and even when shopping for home LED lights it's
surprisingly difficult to find low temperature lights that aren't low on
lumens output.

Pretty much anything over 3000K looks horribly blue at night, and if it wasn't
such a massive pain to find them I'd prefer <2000K.

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Laforet
I have a bigger issue with fluorescent lights: They have a discontinuous
spectrum[0] that can mess with your perception of colour as well as a
noticable flicker that gets worse as the tubes age.

Some of the newer "warm tone" CFL bulbs appears to do better better on these
aspects. [0]:
[http://minerva.union.edu/newmanj/Physics100/Light%20Producti...](http://minerva.union.edu/newmanj/Physics100/Light%20Production/LampSpectra.gif)

~~~
jhanschoo
Don't LEDs have a similar (or worse) spectral profile?

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reportingsjr
LED lights tend to have a much better spectrum than fluorescent bulbs.

[http://www.designingwithleds.com/the-new-cree-tw-series-
led-...](http://www.designingwithleds.com/the-new-cree-tw-series-
led-t8-review-and-teardown/)

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NetTechM
I would argue that people with those crazy LED headlights are even worse.
Since I often work late, I get the pleasure of being temporarily blinded as a
white dwarf passes by at 45mph regularly.

~~~
steveax
And don't even get me started on the LED eye melters that cyclists are running
these days. Some are about as bright as car headlights, but the spread and aim
are inferior - especially since the folks that run those invariably seem to
point them up from the horizontal. I keep thinking about mounting a 8 D cell
maglight on a gimbal on my handlebars to give them a photon in-kind response.

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sgarman
If you see the biker then I think the lights did a good job. I suppose you
could make an argument that it could blind people and they hit
someone/something but I never heard of that happing - I only hear bikers
getting hit because they were not seen.

~~~
djeikyb
i'm a cyclist and i sometimes have to stop and get off my bike and wait for an
oncoming cyclist to pass me (eg, on a multipath). it's not necessarily the
brightness, it's that it's not constructed to be visible (and/or illuminate
the road) without also blinding oncoming traffic. fortunately i haven't ever
hit someone or something while blinded by an oncoming cyclist, but that's in
spite of the crap bike light, not because it did a good job.

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steveax
Yes, me too. I'm a daily bike commuter and am quite sympathetic to the being
seen aspect. This goes way beyond that in some cases. Case in point: a good
chunk of my ride goes through the Portland Springwater corridor. This is a
dedicated bike/pedestrian path. Much of it is unlit at night. I've seen these
riders a half mile ago (~2 minutes) and by the time we're getting close enough
to matter their lights are blinding. It's like a driver who refuses to dim
their high beams for oncoming traffic.

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nickbauman
The article is saying "cool it and dim it" but I think they mean to say "warm
it and dim it". They suggest the temperature should not be above 3000 kelvin.

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jwuphysics
That is because redder colors correspond to a cooler or lower color
temperature. Colloquially, we think of blues as cool and reds as warm, but
blue light is actually more energetic (or "hot") than red light.

~~~
p1mrx
Probably because fire is red-orange, and snow is most often seen reflecting
sunlight.

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jondiggsit
And people go install 4,000 and 5,000K LED lights in their kitchens and homes
because it feels modern, can you imagine the disruption. I always insist on
installing 2,800K at a max with my clients.

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andrewpe
I have a couple of 4k LEDs in my kitchen, but also have much warmer LEDs in
other places around my house. The reason the kitchen is different is so it
feels sterile and clean. The cooler light gives this appearance more than
warmer light. I guess the same reason many places have white counter tops.

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pizza
Not my area of expertise by any means, but maybe quantum dots could be used to
filter only a small sliver of the visible spectrum produced by streetlights.
Maybe there could be very-nearly transparent foils that you could overlay over
your windows that would block just that light.

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mullingitover
> "In addition to its impact on drivers, blue-rich LED streetlights operate at
> a wavelength that most adversely suppresses melatonin during night."

I wonder if this ends up saving thousands of lives by decreasing fatigue in
drivers. The blue light argument seems like absolute hogwash; we're exposed to
orders of magnitude brighter blue light every day. It's called daylight, and
the streetlights dont't even emit UV.

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Dylan16807
If you don't get tired at night, you don't sleep well, and sleep deprivation
is much worse than being tired.

If you think the problem with light at night is hogwash you need to read it
again. Bright light, especially blue light _makes your body react like it 's
daytime_. Do you really think people have forgotten about the sun? You only
hurt your own understanding by being so quick to dismiss others.

~~~
mullingitover
> Bright light, especially blue light makes your body react like it's daytime.

You're preaching to the choir. I'm well aware of the melatonin-reducing
effects of blue light, but the streetlights are a drop in the bucket compared
to phones, televisions, and tablets. The one time I actually _want_ to have my
melatonin levels suppressed is when it's late and I'm operating heavy
machinery.

~~~
Dylan16807
Even when it screws up those levels for hours after you get out of the car?

We could mandate that people driving at night must drink at least one cup of
coffee per half hour, and it would make them be more awake in the short term,
but it would be a terrible idea for similar reasons.

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sevensor
Blue indicator LEDs on consumer electronics are a real plague. I had to cover
the LEDs on a noise machine with electrical tape because of the harsh blue
glow. I had to wonder what on earth the manufacturer was thinking -- this
product is marketed to parents of newborns to help their babies sleep!
Heartbeats, whalesong, blinding blue LEDs, white noise: one of these does not
belong.

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abootstrapper
Could we just place a lens of some sort on pre existing led street lights to
decrease the amount of blue light emitted?

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chiefofgxbxl
A filter to block out a bit of the excess blue light? This would reduce the
effectiveness of the light output though, unless you amped up the output to
raise all of the colors and then selectively suppressed the blue to help
balance it out. Then this would require extra energy, which defeats the
purpose of using LEDs to save energy.

~~~
joshkpeterson
You can just use a different color of LED. Honestly people in Seattle, where
these LED lamps were first piloted, have been raising these concerns for at
least 4 years. This is the product of some combination of bad design, a lack
of user-centered thinking at the utilities, and less than ideal incentives.

For example, daylight led's were touted as making it easier to identify cars
involved in criminal activity because you can see the color of the vehicle
more easily. But how many times has this actually made the difference in
solving a crime?

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analog31
One of the many hats that I wear at my day job is optics designer. An issue is
that the white LED is a particular thing. It's a blue LED coated with a
phosphor that absorbs some of the blue light, re-emits it at a broad range of
longer wavelengths, while also passing some of the remaining blue light
through.

The blue is special -- 473 nanometers -- due to the solid state physics of the
semiconductor.

There is indeed an ongoing search for white LED designs that produce less
glaring blue without sacrificing overall efficiency, but counterintuitively
it's a hard design problem. People also want warmer light in their houses, so
the problem is not limited to street lighting.

The safety regulations have a special place in hell for "retinal blue" light.
As it turns out every wavelength from UV into the IR has a set of weighting
functions for estimating the overall hazard exposure. It's possibly a rare
example of a truly science based regulation.

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joshkpeterson
Is it currently feasible to make LED's at that brightness that are closer to
the old yellow-orange lamps?

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analog31
That's the 64 dollar question. At present, they exist but are less efficient.

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dsmithatx
Any sources to studies done on the effects of light at different Kelvins? I'm
really surprised as I would have expected LED light with more blue and looking
natural to be preferable to orange Sodium Vapor lights. The sun which is our
main light source puts out a wide spectrum. I'm surprised the lower wattage
LED street lamps could cause actual health problems. I'm usually in bed during
sleeping hours and not really exposed to the new blue LED street lights
installed recently in my neighborhood though.

As someone who has always been interested in Astronomy I do worry about light
pollution. Having worked at Observatories I do know that only red light is
used due to it's low impact on light pollution.

~~~
emp_zealoth
LED spectra are usually tiny, sharp spikes, the home ones are getting slightly
better, but the good ones are rather pricy. Incandescent or halogen bulbs feel
more natural to me and their spectra look different

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tjmc
Quite a few inaccuracies in the article which indicate misunderstanding of how
additive light temperature works.

You don't want to "cool it" \- that means more blue! You want to warm it with
less.

~~~
mirimir
"Hot" and "cold" have different meanings in different contexts. In the
article, they're referring to color temperature, which is about the
temperature of the source, and assumes black-body spectrum. So 3000K means a
source at 3000 Kelvins. Light from a 5000K source has more blue, and so is
cooler. But the color temperature is higher (5000K vs 3000K).

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nickhalfasleep
Color temperature of "white" LEDs is due to the amount and type of phosphor to
downconvert the blue LED spike to warmer colors. The more phosphor and
conversion that goes on, the less total output (no free lunch in physics). So
in markets where _amount_ of light (like exterior lighting) is a selling
point, vendors sell their cooler temperature LED's for performance.

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JoeAltmaier
What does the AMA know about LEDs and health? There's nothing in this article
about _why_ they made these recommendations. And the article compares LED
lighting to 'before electricity', instead of to _for instance_ existing sodium
lamps?

It _is_ an opportune moment to make the recommendation, since folks are
converting to LED so rapidly.

~~~
zzalpha
Actually they specifically say why: glare and impact on circadian rhythms.
Both of these are very well studied issues with light concentrated in the blue
end of the spectrum (as opposed to sodium lamps that have very little blue
emissions).

BTW, they also failed to mention increased light pollution due to scattering.

~~~
stephengillie
How well studied are these topics? How many studies involved more than 1000
people?

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Mizza
And what about laptop monitors?

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noir_lord
Someone mentioned flux but on Linux gtk-redshift is awesome time.

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srisa
You saved my eyes!! And that is not an exaggeration. I too recommend gtk-
redshift if you are on Linux.

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noir_lord
I really like gtk-redshift, you can play with the settings in
~/.config/redshift.conf as well I find that a lower gamma even at midday works
well and I tweaked even more towards the red than the default.

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idiomatif1
Actually, I hate LED cause it's too light.

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dang
Url changed from [http://www.cnn.com/2016/06/21/health/led-streetlights-
ama/](http://www.cnn.com/2016/06/21/health/led-streetlights-ama/), which
points to this.

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cauterized
Thank you!

