Monthly Archives: January 2019

Non-Coastal Wildlife Affected by “Blue Rich” LED Street Lights


Thank you for looking the information over.

I am in communication with Dr. Travis Longcore, the expert who authored the NPS report I sent last night. He suggested I pass along the attached document available online at <>, and that I emphasize LED light’s impact on insects as a worthwhile consideration.

I pointed out scientists face a communication challenge in conveying to manufacturers, vendors, and policy makers that "amber" LED is not just for coastal areas. He agreed, and plans to write a follow up on his research blog to better convey the issue.

Personally, I can’t emphasize enough that global insect declines is a frigthening prospect. Apparently, LED light acts as a "magnet" that can effect localized extinctions. Scientists called a new study detailing massive insect decline "hyperalarming" in an October, 2018 Washington Post report:

Below is an image from the paper in LED Professional magazine that Dr. Longcore urged me to share with you. You can see from the figure, 3000 K is "middle ground" of ecological impacts.

Even 2700 K would be better, according to the paper, at reducing impacts to insects. The paper concludes, "[w]ith amber and filtered products on the market, low color temperatures ≤2200 K are feasible and desirable to minimize adverse impacts."

I know safety and engineering standards are important. However, I would have to be convinced 2200 – 2700 range would adversely impact safety, especially on "local" residential streets in Knoxville’s major road plan.

Consider: Phoenix is installing 2700 K, and Washington D.C. is installing 2700 K on residential streets (with 3000 K max). Davis California is using 2700 K, too, in park and greenbelt areas (please note the "Analysis" section of the linked report:

The "Gold Standard" is Sherbrooke, Quebec, which chose 2200 K LED for all its outdoor lighting (it is near an observatory). There are of course Coastal areas using 2700 K: Nantucket Island, Fort Lake, Florida, and others.

Please note the image below showing the "mixed" approach from Washington D.C. for arterial (3000 K) versus residential (2700 K) streets.

I can appreciate I-40, Magnolia Ave, Cherry Street, Washington Ave might need 3000 K lights, to promote true color perception, but I feel the smaller residential streets could benefit from the lower K lights. Referencing our road plan’s distinctions ( could tie the whole thing to zoning.

I am not entirely sure why I am sharing any of this, by the way– I suppose I like the question "why not" more than I like the answer "no." I do hope you are able to use the information to effect some changes, even at this late stage in your project.



On Thu, Jan 31, 2019 at 3:33 PM Erin Gill <egill> wrote:

Thanks for this information.

From: Tanner Jessel [mailto:mountainsol]
Sent: Wednesday, January 30, 2019 7:54 PM
To: Erin Gill
Subject: Non-Coastal Wildlife Affected by "Blue Rich" LED Street Lights


I have gathered some new information from my reading on the topic which I hope might allow you to justify immediately adding "wildlife sensitive" lights to your LED Street Light project for important natural areas– particularly the 20 street lights at Sharp’s Ridge Memorial Park.

Please have a look- I highlighted the key points in bold.

While it’s true some species are more affected than others, the correct answer concerning LED lighting is "all types" of animals are affected.

You are of course correct to question what species might be impacted in Knoxville: a 2017 report from the National Park Service advises "Park managers should first inventory their resources and determine if and where sensitive species or habitats exist."

Sharp’s Ridge is undoubtedly one such "sensitive" habitat, as it is the highest point in Knoxville and its elevation and wooded nature combined make it important to nocturnal migratory birds. Further, it has a predominantly east-west orientation that intersects north-south migrating bird populations.

Moreover, Sharp’s Ridge hosts a dense array of large communication towers. Bright lights at the base of communications towers can draw birds toward the towers, leading to death by impact with either the towers or their guy wires.

As far the ecological impact of 3000 K, please note this paper, "LED lighting increases the ecological impact of light pollution irrespective of color temperature" in Ecological Applications 24:1561–1568 by Pawson, S. M., and M. K.-F. Bader in 2014.

Please also note the 2018 paper by Dr. Travis Longcore and others stating "filtered yellow‐green and amber LEDs are predicted to have lower effects on wildlife than high pressure sodium lamps, while blue‐rich lighting (e.g., K ≥ 2200) would have greater effects." To repeat: anything over 2200 Kelvin has *greater* impacts than existing high pressure sodium lamps.

The optimal scenario for Sharp’s Ridge would in fact be "zero" street lights