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Updated: May 28, 2018

As I rewrite this post now in 2018, I’m curious about how Seattle’s streetlight retrofits have come along. I am especially interested in how they are addressing the issue of too bright LED lights. This problem is ever so sadly making light pollution around the planet much worse instead of better.

At the time I wrote the original post about this, I had read something about what I was experiencing myself in my own Seattle neighborhood. Light pollution was glaring into the private sanctum of my bedroom. The problem was resolved by replacing the post with a new LED as part of Seattle’s streetlight retrofitting.

LED streetlight retrofits – light temperature concerns

The problem really lies in the LEDs themselves. Most city light retrofits have gone with 4000k which is nearly twice as bright as the old sodium lamps that came in at about 2700k. In 2016 there was an article published in CNN’s Health news from doctors warning about the adverse effects of these lights. Furthermore, as I read the reports from Seattle’s retrofit, I am struck by the fact that there is no mention of light pollution. At the bottom of one report is a section about community complaints. The top complaint is light tresspass. The solution is to shield the light. In fact, I think that’s what they did with the light outside my bedroom window because there is much less light tresspass now than there was with the old sodum bulb.

Health risks of LED street lighting according to the AMA

The CNN article talks about the “two problems with LED street lighting.” One, they cause discomfort and glare. The blue content of the LED light is very concentrated and the resultant glare at sufficient levels can actually damage the retina. The second issue they bring up is the impact on the human circadian rhythmicity. Because of the glare, there is light tresspass, which, again, was the biggest complaint that Seattle got from residents after the new lights were installed.

This seems like a train that’s left the station. What will be the solution? Maybe be required to shield all of the streetlights? Part of the problem, of course, is that the model for cities doing these retrofits is cost savings rather than reducing light pollution. Furthermore, studies about the effects of light pollution on humans and animals don’t seem to even have been taken into consideration. So, I guess we’ll just need to stay tuned here, and I will continue to investigate this myself.

Shielded Seattle LED streetlight - the one outside my bedroom window

Unshielded Seattle LED streetlight - the light in front of my house

Seattle LED streetlight retrofits – original post

I got a letter in my mailbox from a neighbor who learned that our old sodium street lights are about to be replaced by LED lights as part of Seattle’s LED streetlight retrofits. However, these LED lights are much brighter and whiter than the old (too bright) sodium lights they are replacing. Not only that, but the brightness of the LED lights are based on whether the street is considered to be arterial or residential. This is not good news for my house because I live on the corner of two arterial streets.

The timing of this is interesting because I just received a response from Seattle City Light telling me that they cannot shield the sodium light outside of my bedroom window. I’m happy they responded at all, they didn’t when I wrote to them over a year ago, but maybe my plea was a little stronger this time (after not being able to get back to sleep in this room AGAIN).

Seattle City Light response to my problem with light trespass

I now have two different contacts concerning this problem and I’ll follow up with both of them. The good news, at least for my ability to get a full nights sleep without having to purchase black out curtains, is that the LED lights can be shielded. The bad news is that for some reason the city’s decision (and it sounds like not only Seattle’s) to retrofit with LED has more to do with cost than abating light pollution. It seems like it’s not even a consideration?

My neighbor’s letter mentions that the city researched the color of the new lights against the old yellow sodium ones. The LED lights are meant to resemble full moonlight. Well the moon is only full a few days of the month. Maybe the lights should lessen in brightness as the moon wanes. Wouldn’t that be nice.