If you’ve played around with “white” LEDs, you already know that there’s no such thing. There’s warm white and cool white and any numbers of whites in-between. And when white LEDs were new, the bluer “cool white” variety were significantly more prevalent.
Enough US states have swapped out their old street lights with LEDs that it may be having a measurable effect on people and on the animals around us. This is the claim in a recent position paper by the American Medical Association’s Council on Science and Public Health. (Report as PDF.)
Science strongly suggests that heavy doses of light can keep people from falling asleep, and that brighter LED streetlamps may be making the problem worse. The AMA report goes a step further, and pins extra blame on the color of the light. Blue light apparently suppresses the production of melatonin which helps you sleep at night. And it’s not just humans whose circadian rhythms are getting messed up — the effects are seen throughout the animal kingdom.
Blue light additionally diffracts funny in your eyeball — we’re sure you’ve noticed the strange appearance of blue LEDs and UV lasers. Add together tired drivers and glare-inducing streetlights, and you’ve got a recipe for disaster, even without taking into account those birds who keep peeping while they should be sleeping.
The benefits of LED lighting are huge, however. From an energy-efficiency standpoint, there’s no comparison. But it may be the case that initial adoption in streetlights ended up being too bright and too blue.
[via The Washington Post]