PBS newshour had a newsbrief on the eurozone trying to implement strictly red led street lights for paths and roads to mitigate a measurable amount of damage to insects, bats, wildlife, even plants caused by standard led streetlights and their particularly bad form of light pollution. They have a neighborhood fitted up with red streetlights as a test as a notable and measurable difference in wildlife activity occurred directly after switching to standard LEDs. https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/final-reports/ca23-3696-finalreport.pdf what I find strange is why are we trying to reinvent the wheel? Turtle habitats, decades ago banned all outdoor lights except for low pressure sodium. Botanical Light Pollution - Red is the New Blue — LED professional - LED Lighting Technology, Application Magazine the old research said red was bad for wildlife as well and only lps was extremely low impact. I’ve seen arguments that lps is inefficient but it’s efficiency is 100% dependent on the ballast type, there were tests of very high efficiency ballasts that brought lps beyond 200wt/lm even beyond typical led efficiency, with the added benefit of faster startup, but the technology was EOL and shelved. LPS can be made cheaply and with long life, I don’t see why we don’t use what works best and I couldn’t find the groups findings or information that show red as being better. I’m the type that if they miniaturized lps, I would use it for my garage and outdoor lights
Doesn't matter what technology produces the light- you could get LEDs that produced only 590nm output like an LPS lamp and gain both the touted benefits of low power consumption and better wildlife compatibility.
Yes, light pollution effects on the natural world were known before LED became the norm. Seems what would be good for animals may not be good for plants by @Rmay635703 second link. Though a narrow wavelength band red LED might be the solution. "One roadway luminaire manufacturer has recently taken this approach with a new product line that was reportedly designed to comply with the International Dark Sky Association’s Fixture Seal of Approval program requirements for a maximum CCT of 3000 K. While the approach works (with a measured CCT of 3145 K), the massive spike in red light peaking at 625 nm (Figure 8) would seem to be a botanist’s nightmare spectrum. Surprisingly, the situation may not be as bad as it appears. First, there is relatively little far-red radiation being emitted. Second, the 625 nm peak occurs where the phytochrome Pr absorptance spectrum is only 50% of maximum. This results in a calculated phytochrome action value (relative to the HPS reference lamp) of 0.9 - half that of the 3000 K LED." That particular product also has white LEDs, so still an issue for animals though. It does show that LED can be the solution. The paper also mentions others.
I was stumped on just the second acronym, so anyway: LED : Light Emitting Diode HPS: High Pressure Sodium