Man, I wish my knowledge allow me to give you the right answer. But it does not and since we’re talking about human safety (safety always 1st) I do not dare to answer. But I’m nearly sure some requirements (made upon research) are given in occupational hearth and safety guidelines. (OSHA?)
My understanding is that blue light specifically is the type of light that impacts the sleep cycle, as opposed to red or green. And for this reason, warmer/cooler CCT lights have different effects. I've easily observed this in my own life: one room of my house has 2700K lighting, and I will fall asleep if I try to read a book in that room. The other areas of my home have 4000K to 5000K lighting, and I have no issues reading and staying awake there.
Anyway, this becomes an issue when significant blue-light invades spaces where it hasn't always been. Cool-CCT streetlights in particular could be an issue, as they shine at night. If people aren't aware of the impacts of blue light on their sleep schedules and/or don't accommodate for that impact in their life, they'll have sleep cycle disruptions. This can range anywhere from decreased quality of sleep to straight-up insomnia. In fact, I had seen studies showing this impact comparing dark vs. brightly lit neighborhoods already (wish I still had that source), and I'm not surprised at all that adding more blue light would strengthen the effect.
My answer is to move into my warmly lit room at the end of the day and wind down there. Also to limit screen usage and/or blue-light filter the screen. And lastly, blackout curtains ;)
TL;DR: It's long been known that light affects sleep, more blue spectrum means stronger impact, and sleep impacts everything else
It’s like a magic cancer-wand. Point it at a bad guy and bam! Dude dies of cancer, and doesn’t even get to die in his sleep. Teaches him right for lurking around an alley in the dark.
I knew there was a reason why I kept all those crappy LED maglites.
I thought using a cool white for not so long on and off during a night duty LEO shift would be ok as It wasn’t excessive.
not sure, maybe best stick to NW/ Warm
For those concerned and using firefox, opera or chrome without a built in color temp changer, this add on is very handy. It’s not automatic, but just leaving it on all the time isn’t that bad either.
The quotes from the article seem to answer a lot of the questions here. The issue is constant, bright, high-CCT street lighting being linked to changes in sleep patterns/hormones.
I would think it’s a combination of factors that link this all together. IMO it’s mostly to do with ones lifestyle. If you’re up late regularly chances are you could be in the presence of bright light which further interrupts the sleep cycle.
At the bottom of the first paragraph “Researchers found that night shift work links to breast cancer because it can change a person’s sleep-wake cycle. This has a lot to do with artificial light.”
AsI recall, it takes only a brief exposure — think incandescent white nightlight bulb — to suppress melatonin production. Then it takes half an hour to an hour for the body to resume produccing melatonin. It’s the melatonin that suppresses breast cancer (which is why night shift workers and people in areas newly supplied with nighttime electricity show an increase)
I used my kit spectrometer to check the claims of bluelight suppression. A lot of it is hype — f.lux for example changes the apparent color temperature by adding more red, rather than removing blue. The spectrometer shows plenty of blue light still being emitted from the computer screen (whether fluorescent or LED lit).
I swapped amber LEDs into half our home flashlights, for nighttime use, and for room lighting we use amber LED bulbs or “bug light” compact fluorescents for evening light during the short-day half of the year.
Doing that cured our insomnia, which had gotten bad when we replaced all our incandescents with “white” compact fluorescents some years ago.
I think CCT is actually still a huge part of what’s happening there. Even 2700K light from a blackbody source will have far less of the blue end of the spectrum compared to 4000K.