ALAN's a problem we can solve

By Anaheim Events, Fair use, https://en.wikipedia.org/w/index.php?curid=66761286

This is a story about pollution that, amazingly, actually has a happy ending.

Artificial light at night (or ALAN) is creating light pollution at unprecedented levels. Night skies have been getting 10% brighter every year since 2011 -  equivalent to doubling the sky brightness every 8 years. (1)

There are 3 types of light pollution:

• glare (which the poor woman in this photo is experiencing)

• light trespass (literally, one person's lights trespassing onto their neighbor's property)

• skyglow (human-caused light scattered in the atmosphere).

ALAN-related light pollution is getting worse because cities across the country - including Stillwater - are increasingly changing out their old street lights for LED versions that are much more energy efficient and therefore more cost-effective.

But oops! Never forget the law of unintended consequences. In the process of updating their lighting, cities created a set of new problems, because most LEDs in use today are

So.

Damn.

Bright.

To briefly summarize the mountain of scientific data out there, high-intensity LED lighting impacts wildlife such as birds (affecting their migratory behavior (2,3), breeding, and sleep-wake cycles), insects, and aquatic life.

For humans, bright LED light can paradoxically create a safety issue, according to the American Medical Association: nighttime glare is worse than with conventional lighting, and intense, blue-rich LED lighting can decrease visual acuity and safety, creating a road hazard.

ALAN is not just a big-city issue; according to the USFWS Columbia Pacific Northwest Region, "light pollution can be a problem in small towns because of their proximity to wildlife habitat. Although small towns produce less artificial light, their light can have a bigger impact, particularly on nocturnal birds and animals."

But Sirid! I can hear you saying. You said there's a happy ending to this story!

Yes, unlike other distressing tales of pollution, light pollution DOES have a happy ending with immediate effect; provided cities across the country install the right kind of LEDs in the right kind of luminaires. Good street lights should have at least one of the following features:

• Luminaires that minimize "up-light" that causes skyglow - that is, they have shielding and/or a tilt angle that directs the light down.

  

  Luminaires, from best to worst when it comes to ALAN. (Source: https://www.radiantvisionsystems.com/blog/nighttime-outdoor-lighting-and-challenge-light-pollution)

• "Smart" features that allow dimming or motion activation.

• PERHAPS MOST IMPORTANTLY, LEDs that have a "warm," yellow-hued light, with a Kelvin rating no more than 2100 K.

  • Blue-white LEDS have a much higher Kelvin rating. Blue light's shorter wavelengths are more easily scattered, so blue light contributes to glare and skyglow, and is more likely to disrupt the circadian rhythms of people and animals.

  • Although we think we can see better under a whiter light (and we therefore feel safer), what's actually happening is that white light allows us to see a greater range of colors, giving the sensation that we can see better.

Sorry to say, Stillwater appears to be installing a type of unshielded "period" acorn design luminaire downtown. (There are dark-sky friendly acorn-style luminaires out there, but I'm not sure if a retrofit is possible in our situation.) The good news is they will be smart, dimmable lights. (I hope, but do not yet know, what Kelvin rating the LEDs will have.)

The lesson I take away from this? Our city has smart, thoughtful staff that do a tremendous job keeping our little city beautiful and safe. But in a great city, there is a shared responsibility: It's up to us residents to participate actively by contributing our thoughts, questions, and expertise to make things even better, and it's up to our local leaders to listen. It's what I've said before: Local government should be community-inspired and community-driven. It works.

1. Kyba C, Altıntaş Y, Walker C, & Newhouse M. (2023). Science 379: 265-268. 10.1126/science.abq7781.

2. Van Doren B, et al. (2017). High-intensity urban light installation dramatically alters nocturnal bird migration. Proc Natl Acad Sci USA 114: (42) 11175-11180. https://doi.org/10.1073/pnas.1708574114

3. Cabrera-Cruz SA, Smolinsky JA, & Buler JJ Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world. Sci Rep 8, 3261 (2018). https://doi.org/10.1038/s41598-018-21577-6

4. American Medical Association (2016). AMA adopts guidance to reduce harm from high intensity street lights. Press release. https://www.ama-assn.org/press-center/press-releases/ama-adopts-guidance-reduce-harm-high-intensity-street-lights

5. Evergreen, S. (2022). Bright LEDs could spell the end of dark skies. https://www.technologyreview.com/2022/08/17/1057652/outdoor-led-lighting/