
Some cities are taking another look at LED lighting after AMA warning - petethomas
https://www.washingtonpost.com/national/health-science/some-cities-are-taking-another-look-at-led-lighting-after-ama-warning/2016/09/21/98779568-7c3d-11e6-bd86-b7bbd53d2b5d_story.html
======
keenerd
Let's break down their claims.

> unseen blue light

I have unread negative comments about this sloppy writing.

They also repeatedly use the word "intense" incorrectly. Intensity refers to
candela. Not lumens or temperature.

> The original LED streetlights had temperatures of at least 4000K, which
> produces a bright white light with a high content of unseen blue light.

4000K is actually considered fairly mellow. Above 6000K, then things start to
get blue. The earliest white LEDs were around 10000K and terrible.

> Now, however, LEDs are available with lower kelvin ratings and roughly the
> same energy efficiency as those with higher ratings.

And now the higher kelvin lights are even more efficient. White LEDs use
phosphors to shift the blue light to longer wavelengths. This is a lossy
process. Low-K tints require more phosphors and reduce efficiency. That said,
4000K looks so much nicer than 6000K that the loss is worth it.

> “As a species, we weren’t designed to see light at night,” Siminovitch said.

We've had mastery over fire for as long as we've been a species. Darkness is
unnatural to humans.

Moonlight is around 4100K. So it is even more "natural" than 3000K. Should we
blot out the moon next?

> it urged cities to minimize blue-rich outside lighting and recommended the
> use of LEDs no brighter than 3000K.

Confusing color temperature and brightness again.

And now from the AMA's press release:

> Recent large surveys found that brighter residential nighttime lighting is
> associated with reduced sleep times, [etc]

It seems no one has blinds in their windows. I always carry an eye-mask with
me too, just in case.

The AMA press release is very low on actual content so I can't comment on most
of it. They are smart enough to avoid mentioning the "blue light causes eye
damage" myth for example, sticking to meaningless wishy-washy statements.

If the people raising a fuss over LEDs actually cared, they would have been
campaigning against mercury-vapor and high-intensity-discharge lamps for the
past several decades. A 4000K LED puts out way less blue light than either of
those technologies.

~~~
fian
> Moonlight is around 4100K. So it is even more "natural" than 3000K. Should
> we blot out the moon next?

I was on a hike in July during a full moon and those who were sleeping in open
air (no tent or bivy bag) struggled to sleep through the night due to the
moonlight.

This was in the North West of Australia, so daytime maximums were around 35C.
It was too warm at night to zip your tent or bivy closed, so where possible
you would try to position yourself so that you could shield yourself from the
moonlight during the night.

There were quite a few afternoon nappers in the group until the moon waned a
little by the second week.

~~~
keenerd
No one carried a bandanna that they could use as an eye mask? I've done that
even when the night time low was 35C.

~~~
TeMPOraL
In situations like that I use any random piece of clothes as an eye mask, so
yeah, I don't see a problem either.

------
phonon
Here is the actual AMA report.

[http://darksky.org/wp-content/uploads/bsk-pdf-
manager/AMA_Re...](http://darksky.org/wp-content/uploads/bsk-pdf-
manager/AMA_Report_2016_60.pdf)

A representative section.

"It is estimated that a “white” LED lamp is at least 5 times more powerful in
influencing circadian physiology than a high pressure sodium light based on
melatonin suppression. Recent large surveys found that brighter residential
nighttime lighting is associated with reduced sleep time, dissatisfaction with
sleep quality, nighttime awakenings, excessive sleepiness, impaired daytime
functioning, and obesity. Thus, white LED street lighting patterns also could
contribute to the risk of chronic disease in the populations of cities in
which they have been installed. Measurements at street level from white LED
street lamps are needed to more accurately assess the potential circadian
impact of evening/nighttime exposure to these lights."

------
vvpan
This follows tit-for-tat the story of every other street lighting development
in the past. It gets invented, implemented, lauded and then disappointment
sets in. At least according to a fairly exhaustive book on the topic called
_Disenchanted Night: The Industrialization of Light in the Nineteenth Century_
[1]

[1]
[https://www.goodreads.com/book/show/350025.Disenchanted_Nigh...](https://www.goodreads.com/book/show/350025.Disenchanted_Night)

------
bunderbunder
Seems like there might also be an opportunity here:

    
    
      - Install the ones that keep people awake along highways and suchlike.
      - Install lights that don't disturb sleep so much in neighborhoods.

~~~
Bud
No. The lights aren't effective at keeping sleepy people more awake in the
moment. They're effective at disrupting sleep over time by disrupting the
hormonal system.

They should be banned in favor of lower-color-temperature lights.

~~~
criley2
>They should be banned in favor of lower-color-temperature lights.

As the article indicates, they are less effective at disrupting sleep than a
LCD monitor or smartphone.

If we're banning an outdoor light for being less disruptive than your phone,
should we also mandate Flux style warm color phones at night by law?

~~~
klipt
Why not. I already use flux on my laptop and would love it if my phone
supported that too.

~~~
afarrell
[http://www.macrumors.com/how-to/use-ios-9-3-night-shift-
mode...](http://www.macrumors.com/how-to/use-ios-9-3-night-shift-mode/)
[https://play.google.com/store/apps/details?id=com.urbandroid...](https://play.google.com/store/apps/details?id=com.urbandroid.lux&hl=en_GB)

~~~
icebraining
Maybe it's just me, but Twilight never felt as pleasant as f.lux and redshift
do on my PCs. Instead of changing the screen color, it seems to add a red
layer over the content.

EDIT: It's not just me: [https://forum.justgetflux.com/topic/2591/exactly-why-
do-you-...](https://forum.justgetflux.com/topic/2591/exactly-why-do-you-need-
root-for-flux-android)

------
phasetransition
I'm head of engineering for a company that designs outdoor luminaires for
industrial environments, but not street lights. We use LED and other
technologies. Like so many things in life, there are aspects of the AMA
directive with potential cause for concern, but also combined with a mixed bag
of scientific underpinnings. If you have specific questions about LED physics
or human vision, I'm happy to give them a go. I also can speak to some of the
literature behind the AMA position paper.

~~~
raziel2701
What temperature LED light should I have for my bedroom?

~~~
phasetransition
Essentially any LED bulb that you can buy is a blue diode with a down
conversion phosphor. The composition of the phosphor, and the relative amount
of blue light vs. phosphor emissions shape our perception of color temperature
for these LED sources.

Due to an effect called metamerism, our brains can perceive the same apparent
color from sources with different underlying spectral power distributions
(power vs. wavelength).

So in a sense, the color temperature of a black body does not have much
underlying connection with the spectral power distribution of LED lamps.

With that substantial caveat, the lower the correlated color temperature of
the bulbs that you purchase, the less of the overall spectral power is from
the diode, and the more from the phosphors.

If there ends up being a link to blue light exposure for circadian effects
then bulbs with lower CCT that have more emission from the phosphors are the
safer bet.

~~~
jacobolus
Some LEDs have phosphors which almost entirely absorb the light from the
diode.

~~~
theatrus2
For example, Lumileds PC Amber and Lime LEDs employ this trick. They're
usually used as a corrective color component and not the main lumen source.

~~~
phasetransition
I've not seen the PC Amber data from Lumileds, but I can vouch that their lime
color LED has no blue diode emission peak visible in the spectra.

------
fpoling
While that may improve sleep, it may also made driving less safe. With blue
light it is easy for eyes to focus. In fact there is a theory that significant
increase in myopia during the last 100 years is caused by eye work under
artificial light without blue color, like from ordinary light bulb...

Edit: I should have written "without blue light in spectrum eyes work harder".
Basically any deviation from the spectrum of Sun have cosequences for eyes
performance long term

[http://www.eyedolatryblog.com/2014/02/myopia-may-be-
reversib...](http://www.eyedolatryblog.com/2014/02/myopia-may-be-
reversible.html?m=1)

~~~
honkhonkpants
First time I've heard that it is easy to focus blue light.

[https://www.google.com/search?q=is+it+hard+to+focus+on+blue+...](https://www.google.com/search?q=is+it+hard+to+focus+on+blue+light)

~~~
fpoling
I should wrote about focusing in light without blue component, not focusing
under blue light.

[http://www.eyedolatryblog.com/2014/02/myopia-may-be-
reversib...](http://www.eyedolatryblog.com/2014/02/myopia-may-be-
reversible.html?m=1)

------
jqkeller
I've worked on a few street light retrofit projects and the AMA warning is a
little overblown and frankly immediately outdated.

This is off the cuff, but it comes down to circadian rhythms being influenced
by the color of light. Before artficial light, the sunrise and sunset have a
softer light with a lot more red wavelength in it. This would correspond more
closely with the color of light from an incandescent, like 2500-3000 Kelvin.
The mid day light has a lot more blue wavelength in it relatively, where it is
much more of a White light, I think daylight is like 15,000K. The high
pressure sodium, HPS, lights have an orange light in the 2,200K range. The
majority of LED street lights being installed are 4000-5000K, so they have a
lot more of the blue light. Essentially the blue light tricks your brain into
thinking it's mid day and messes with your sleep patterns.

The first generations of LED street lights could really only effectively make
the 4000-5000K light. With new generations coming out every 3 months or so
though they have been able to create models that can generate the 2500-3000K
warm red light, but they're not quite as energy efficienct as the 4000K lamps,
maybe 10% or something. The 2500K is actually better for the Dark Sky
movements as well and a lot of cities are moving to specify these warmer
temperature for those reasons.

There are a whole bunch of other things going on as well. The road way
lighting standards were designed around the light patterns of a HPS lamp and
haven't been updated to reflect the light patterns possible with LEDs, hence a
lot of LED projects have too bright of streets.

For the sleep pattern issues, when you're installing LED lights in your home,
you want to put the warm lamps, 2500-3000K, lamps in bedrooms and such. Then
for living spaces or offices you'd want to put the 4000K lamps to help keep
you awake during the day. There are also lamps/fixtures available that will
automatically tune the color output of the light to be in sync with the
outdoors to help keep circadian rhythms in sync.

This company has been pushing the tunable lamps hard.
[http://www.planled.com/archives/portfolio-item/entraining-
ci...](http://www.planled.com/archives/portfolio-item/entraining-circadian-
rhythms)

[http://humancentriclighting.org/](http://humancentriclighting.org/) This site
appears to be fairly dead, but they were more of an independent group
promoting it the last year or two.

~~~
keenerd
> I think daylight is like 15,000K.

No, it is 5500K or 6500K depending on which metric you use.

~~~
pYQAJ6Zm
I always felt confused between the 5500 / 6500 K pair. What metrics are
involved?

------
jackyinger
Yes! I am not crazy! Seriously, do we really need lights that make the city as
light as in the day? I'd rather give my retinas a rest.

~~~
lake99
> as light as in the day

It's got nothing to do with intensity, which would be impossible to achieve,
for all practical purposes. The article misused the word here. Rather, it's
about color temperature.

I think this problem is overblown, because I've not heard similar complaints
leveled against mercury-vapour lamps. I've grown up around them nearly all my
life.

~~~
jackyinger
When you replace 1:1 vapor laps with LEDs an adequately lit parking lot
becomes lit like a stage.

Though to your color temp point, if we could get lower color temperature
that'd be great. IIRC red LEDs are much more efficient than full spectrum
anyway.

------
userbinator
All the studies I've found seem to say something along the lines of "blue
light disturbs sleep", which seems like exactly the needed effect if you're
driving at night.

~~~
droopyEyelids
You're thinking of 'promoting wakefullness' like a cup of coffee that has an
immediate effect that wears off when it leaves your system.

'Disturbing sleep' means they alter your hormone production & release, which
is something that begins to affect you over weeks and months.

High color temperature lights disturb sleep- without promoting wakefullnes.

~~~
abz10
The light has an effect during the night as it blocks the melatonin hormone
from kicking in. It takes about an hour of darkness for the hormone kick in
and make you sleepy. On very long occasional drives it's probably safer to
trade some sleep disturbance for a more wakeful drive. If it's your daily
commute it'll probably mess up your sleep.

~~~
cauterized
And if it's on your residential block, it'll definitely mess with your sleep.

~~~
abz10
Yeah, screw that. I wear some cheap blue blockers before bed. I look like Bono
but it works :)

------
hocuspocus
Somewhat related, I've always wondered why _outdoor_ solid shutters or blinds
are a given in some countries/regions but nowhere to be seen in others, even
though some residential areas are extremely polluted by artificial light at
night.

~~~
keenerd
Those were historically used to prevent damage to window panes, not block
light. They are popular in areas that were settled when glass was very
fragile/expensive and receive strong winds. Pre-glass, they were used to keep
weather from blowing through the house.

------
ivan_ah
On a related topic, y'all should check `f.lux` for removing the blue hues from
your monitor after 9pm: [https://justgetflux.com/](https://justgetflux.com/)

------
jkmcf
_Meanwhile, the “dark sky” movement criticizes LEDs as a major contributor to
what it calls the “light pollution” that humans cast into the night sky._

As a former, quasi-astronomer, nothing at night is more impressive than a star
lit sky. My first night in Colorado was unbelievable.

~~~
0xffff2
Really? I thought one of the major advantages to LED street lighting is that
it is much more directional, so it leaks less light into the sky.

~~~
jkmcf
20+ years ago, sodium (?, same as below?) lamps were suggested but supposedly
people didn't like how things looked (IIRC) in the light.

[http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-
li...](http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-light-
pollution/) says low pressure sodium lamps significantly improve star viewing
compared w/ LED due to the narrower spectrum.

Downvote science, bitches.

------
mtalantikite
I had LEDs installed in the streetlight in front of my apartment in Brooklyn a
few months ago and my living room is now awash with this light. It's terrible.
I noticed my sleep time pushed further and further back and I've resorted to
supplementing melatonin regularly so that I can fall asleep earlier than 2 am.
I've complained to the city and have considered moving since I don't think NYC
will swap ours back.

~~~
keenerd
Please, put in blinds. If you have blinds, put in curtains to catch the light
that spills around the blinds. If too much light goes through the blinds,
upgrade to window shades. If that isn't enough (or you don't want to spend any
money on interior decorating), get an eyemask. If $2 for an eyemask is too
much, drape a t-shirt over your eyes.

Moving is a comically inappropriate response.

~~~
rbanffy
If moving becomes a common response, we can use street lighting to fight
gentrification. Don't discourage it.

~~~
mtalantikite
That's assuming city services go to all neighborhoods evenly, which certainly
isn't the case unfortunately. Most of Brooklyn is covered now, but only 1/3 of
Queens and none of The Bronx other than highways have been converted.

------
CodeWriter23
Can't they simply get units with a 2800K white point?

~~~
GarrisonPrime
I'm sure the LED manufacturers will take full advantage of this opportunity to
create "true-light healthy LEDs", for which they can charge double or triple.

~~~
semi-extrinsic
You can already get some (actually really nice) LEDs for your house that
change color to lower temperature (more orange/red) as they dim, mimicking the
effect of dimming incandescents. It does make for a nice cozy atmosphere. As
you say, they're not cheap, but I'd consider them strongly if I were
redecorating.

Edit: it's confusing that a cool blue light is a high temperature, and a warm
orange light is a low temperature.

------
ChuckMcM
It is a confusing story, and not well supported by actual facts or studies. So
I wonder about these things, who has it in for street lights? Crooks obviously
it makes their life harder (and it mentions in the article that police are
getting better witness descriptions under LED lights). And presumably the
folks who made the old Mercury Vapor lights. Which happen to have about 1/10th
the cost to make as LED lights but seem to sell for the same amount, so
perhaps their margins are getting squeezed uncomfortably. Power companies of
course, who could depend on the electricity load coming from inefficient
street lights finding that one of their biggest consumer at their lowest
utilization time is cutting their power requirements by 33% or more. That has
to hurt you really don't want to turn off base load during the night. And of
course people who liked the look of their street before and now are sad
because it looks different[1].

[1] When people switched from coal fireplaces to gas heat a common complaint
was that it didn't smell like home any more.

------
Philip_with1L
I remember reading here in Pittsburgh that the new street lights could be
addressed individually or as groups and have their white points adjusted. I've
never seen this in action and I haven't researched it further. But if they
could be adjusted to be less blue, we'd still benefit from the energy savings.

------
ocschwar
Given that white LEDs rely on blue LED components, and blue LEDs are the most
expensive and most delicate parts in these lights, one would think lowering
the blue content should be a no brainer. More comfortable and cheaper all
around.

------
wamatt
FTA _' “Nobody says don’t watch television or use your computer after 9 p.m.
because of blue lights,” he said.'_

Yeah about that. Seems we have a ways to go still wrt nocturnal blue light
usage and health advocacy.

------
ianai
Do car headlights while you're at it.

------
Animats
I've had it with "warm, yellow" street lights. Redwood City, CA standardized
on low-pressure sodium lamps decades ago. Other than the Golden Gate Bridge,
almost nobody uses those deep yellow lamps any more. (The Golden Gate Bridge
switched to high-pressure sodium in the 1970s, and LEDs recently, but put in
amber lenses to maintain the old color.) Redwood City is finally going LED,
and streets look much brighter.

------
misnome
What exactly is "unseen blue light"?

~~~
jackyinger
I think they mean that there is a lot of blue light emitted, but it is not
super obvious because they emit longer wavelength light as well (reds &
greens).

------
tracker1
Wouldn't filters or rough refraction surface help offset the risks? Of course,
I kind of feel that in climates with snowfall, the bulbs that generate heat
are probably better for keeping said snow from building on the street
lamps/lights.

------
scythe
I'm not sure what the point was in the first place? Sodium lamps approach 200
lumens/watt. LEDs are whiter, but whiter light doesn't necessarily help you
drive, does it? If the concern is colored signs, light the signs?

~~~
jacobolus
Big point #1 was federal subsidies and big new contracts for lighting vendors.

Big point #2 (an actual advantage now) is reduced maintenance cost because the
lamps (theoretically) last longer between replacements.

The energy efficiency claims were always a red herring.

------
amelius
You can buy blue-blocking glasses. So perhaps they can fit these streetlights
with these filters.

~~~
dpark
Of course you _can_ do that. It's just a terrible idea because it drastically
reduces the efficiency and output of the lights.

