* https://www.darksky.org/our-work/lighting/lighting-for-indus...
When it comes to using lights that actually allow the night sky to be seen, that's kind of the point.
Here ( https://upload.wikimedia.org/wikipedia/commons/c/cf/Tokyo_To... ) is a pic of the Tokyo Tower in Japan => I read that apparently they often use yellow light during winter on snowy/foggy days to provide a sense of "warmth", during summer they tend to use more often white light => interesting.
I know it's psychological, but white light also gives me a better sense of security walking at night on the street.
* https://www.darksky.org/why-is-blue-light-at-night-bad/
Another study on crime and streetlights:
> A 2015 study published in the Journal of Epidemiology and Community Health found that streetlights don’t prevent accidents or crime, but do cost a lot of money. The researchers looked at data on road traffic collisions and crime in 62 local authorities in England and Wales and found that lighting had no effect, whether authorities had turned them off completely, dimmed them, turned them off at certain hours, or substituted low-power LED lamps.
* https://www.darksky.org/light-pollution/lighting-crime-and-s...
1. Much blue-er and so WAY worse for people's circadian rhythms 2. Much "sharper" in it's shadows, so you go from blindingly bright to pitch black without your eyes having a chance to adapt, making it unsafer, and making the shadows "darker" 3. Much harder to filter out for astronomers
It's only advantage is really that it's a lot more energy efficient, but it seems like white LEDs are a net decrease to human welfare as opposed to yellow sodium lamps.
Anecdotally, I used to live in front of a park that had yellow lamps and it was never an issue at night, but when they switched to white LEDs my entire house was illuminated with very blue, daylike-like light, really messing up my sleep.
There is always garbage out there, regardless of product category. For streetlights you can get good products. Acuity's Autobahn Series ATB0:
> White Light: Correlated color temperature - 4000K, or optional 2700K, 3000K or 5000K, all 70 CRI
* https://img.acuitybrands.com/public-assets/catalog/122046/at...
* https://americanelectriclighting.acuitybrands.com/products/d...
* Via: https://www.darksky.org/our-work/lighting/lighting-for-indus...
> 2. Much "sharper" in it's shadows, so you go from blindingly bright to pitch black without your eyes having a chance to adapt, making it unsafer, and making the shadows "darker"
Lighting and crime (prevention) is debatable:
* https://www.darksky.org/light-pollution/lighting-crime-and-s...
Further, glare can blind people so as to not being able to see in darker areas:
* https://cescos.fau.edu/observatory/lightpol-security.html#Gl...
> 3. Much harder to filter out for astronomers
IMHO we can start worrying about this after we actually reduce light pollution. If we're at the point that astronomers can actually do useful work around large urban centres then let's start worrying about spectrum. As it stands they probably can't do much of anything now.
Is there a solid research behind this? I know it was intensely shared, but it that real or is it just some idea with none to very limited backing like learning styles.
It's a shame, because LPS was the gold standard for astronomy as the hyperspecific emission spectrum made it extremely easy to filter out for astrophotographers and telescope users
Anyway, sodium lamps are being replaced by white LEDs.
Meanwhile, Harvard Health [2] and WebMD [3] also both continue to report that blue light suppresses melatonin production for humans.
From Time: "Animal studies should always be taken with a grain of salt, as they often do not translate directly to human behavior. And there are additional caveats to this particular paper, says Dr. Cathy Goldstein, a sleep specialist at Michigan Medicine. The researchers looked specifically at cones in the animals’ eyes, which detect color, instead of melanopsin, which senses light and is central to the issue of melatonin secretion.
"They also kept light levels dim, regardless of color, which may not reflect the bright lights of electronics.
"And finally, though mice are frequently used in sleep research, Goldstein notes that since the rodents are nocturnal, they may respond differently to light than humans do. Taken together, Goldstein says these conditions mean the study’s results apply only to a very narrow set of circumstances and metrics. “For this to get extrapolated to saying ‘blue light at night isn’t bad for you’ is a little bit of an extension,” Goldstein says."
[0] https://time.com/5752454/blue-light-sleep/
[1] https://www.cell.com/current-biology/fulltext/S0960-9822(19)...
[2] https://www.health.harvard.edu/staying-healthy/blue-light-ha...
Um this is scary, isn't it? I want cities across the world to start switching over to low pressure sodium lamps. Yellow light for the win!