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KANSAS CITY, Mo. – As soon as the sun goes down, glaring, orange streetlights switch on, illuminating Kansas City roadways.

But skyglow and smog can blanket the night sky, outshining the stars, the moon, and even the flashing lights of airplanes gliding up above.

“We have a history, since the beginning of time, of being connected to the stars,” Mary Nemecek, committee chair for the Burroughs Audubon Society of Greater Kansas City, said. “We risk being the first generation ever that does not have a connection to the night sky if we can’t see the stars.”

Last month, Kansas City Council passed an ordinance for a contract to replace 84,000 high-pressure sodium streetlights with cost-saving and energy-efficient light-emitting diode (LED) fixtures and bulbs.

The lights are said to have higher visibility, require less maintenance, use up to 50% less energy than standard bulbs, and reduce carbon emissions, according to a press release.

“We’re really excited about the CO2 emissions savings, the maintenance cost savings, the savings to taxpayers, as well,” Maggie Green, media relations manager for Kansas City, said. “There’s so many good reasons why we want to go ahead and take this opportunity right now, and I think we’re building in some opportunities to learn and grow along the way.”

Kansas City’s approach

Mahmoud Hadjian, division manager and assistant city engineer of Kansas City’s street lighting program, previously told FOX4 the city originally planned to install LEDs that have color temperatures ranging from 3000 to 4000 Kelvin.

“Under the 4000, you can detect objects a lot better,” he said. “So that’s one of the reasons we are thinking arterial streets, where we have higher speeds in play on the road.”

However, the city has since decided to install LEDs not exceeding 3000 K, pointing to community feedback, wildlife concerns, and other cities as driving factors in the switch.

“The reasons for pursuing this option are multifold: to improve the quality of the light emitted, to create a more natural lighting, to have a unified color temperature across all the streetlights in the conversion project and to minimize impact to wildlife,” Green said in an email.

The American Medical Association (AMA) recommends outdoor street lighting at night not exceed a color temperature of 3000 K because the higher the Kelvin, the more blue light is emitted. A higher color temperature rate typically infers greater blue content, meaning lighting appears whiter, with more glare.

According to the International Dark-Sky Association, the recognized authority on light pollution, 3000 K products emit less blue light, decreasing skyglow and are more cost and energy efficient, safer, better for human health and wildlife conservation.

“The debate is, of course, we should move to LED lights, but what kind of LED lights and how do we regulate the intensity of the lights? Given that it’s more efficient, there’s a tendency to use too much of it and we all know too much of anything isn’t good,” said Dr. Vayujeet (Vayu) Gokhale, associate professor of physics at Truman State University in Kirksville, Missouri.

The Great Debate: Are LEDs safe for humans?

Potential risks linked to LEDs is a topic of frequent dispute among lighting and healthcare professionals.

The AMA released a statement in June 2016 arguing LED streetlights are too bright, “operating at a wavelength that most adversely suppresses melatonin.”

The policy states that “discomfort and disability from intense, blue-rich LED lighting can decrease visual acuity and safety, resulting in concerns and creating a hazard” on roadways.

But in 2016, an American Council of Science and Health (ACSH) article countered the AMA’s stance, arguing if LED light rays were such a problem, doctors would have warned the public of this threat long ago, especially in regards to cell phones and tablets.

“Just because there is a basis to state that a reduction in melatonin is less than optimal, it is another thing altogether to claim that any melatonin reduction is harmful,” the ACSH cites.

The Illuminating Engineering Society has also challenged the AMA’s stance since before its release.

“Just because LED light sources have a blue peak in their spectral power distributions doesn’t mean they emit more blue light in total, or that they have more potential to cause retinal, material, or photobiological harm,” the IES stated in a 2015 article.

Tram Fenimore, engineer and project manager of Kansas City’s Street Lighting Program, and member of the Illuminating Engineering Society, said the AMA’s statement is “really inconclusive” because it only focused on one study.

She said the city is working closely with the AMA, as well as the International Dark-Sky Association, to determine whether LED street lighting has harmful impacts.

“Right now, it’s still inconclusive and we’re working to define what are safe levels, if there are hazards with each type of light, or not,” she said.

But Vayu said the AMA’s statement warning the public of the risks associated with high intensity lighting is stronger than any counter argument skeptics offer.

“Where is the study to show that lights above 3000 K are good for everybody?” he said. “There is no such study, so you can’t say there are not enough studies about whether 3000 and below is safe if you don’t have studies that show the other case either.”

Dimming blue light

According to a city engineer, whether it’s a residential or arterial street, every streetlight has a shield to keep the 3000 K light from scattering upward, to not disturb the evening sky.

Nemecek, with the local Audubon Society, said conservationists are supportive of the city’s decision to switch to LEDs, but fear light pollution will worsen health conditions for citizens and wildlife if the city installs them without proper dimmers or timers.

“Just switching to LED lights seriously risks brightening our night skies, which, in turn, imperils wildlife and has negative impacts for people, as well,” Nemecek said.

Dimming technology was not built into the current citywide LED conversion project, according to the city’s media manager.

Hadjian said the city is installing LEDs designed with components capable of smart controls, like dimming, but does not plan to install them just yet.

“The controls, at this time, just do not represent that payback for us due to the fact that we don’t really have the utility tariffs that are required to be able to take advantage of the dimming,” Hadjian said.

He said the city needs to establish a tariff with Evergy to grant officials full access to lighting controls. It’s something Gina Penzig, manager of external communications at Evergy, said costs extra money and takes up time while under review of the Missouri Public Service Commission.

“Commission requirements allow some edits to be achieved in a month or two, while others may require filing as part of a general rate proceeding, requiring about 11 months,” Penzig said in an email.

Christian Monrad, electrical consulting engineer at Monrad Engineering in Tucson, Arizona, said dimming systems provide more energy savings and extend the lifespan of light fixtures.

“The more they are dimmed, the longer they last due to less heat buildup,” he said. “Also, the network control system allowed supervision of the lights so that the city would know if they are functional or nonfunctional, to where maintenance activities could be done on a more proactive basis.”

He said the dimmers helped Tucson save enough money in maintenance and energy costs to which it was able to pay off any additional expenses related to the dimmers.

Additionally, Monrad said Tucson has seen a 7% reduction in skyglow since installing the LEDs and dimmers.

Vayu of Truman State said if the city waits to install them, rather than installing along with the new LED lights, the city is going to waste time, money, and hurt the city’s ecosystem.

“You install the lights first, and then five years later, you decide that you want the dimmers — that’s obviously going to cost more, but on top of that, dimming, firstly, there’s a direct energy savings,” he said.

“You’re burning less electricity, you’re going to save some money, but the dimming increases the lifetime of your lights and one of the biggest recurring expenses for any city, or any institution really, is maintenance costs, because you need humans to go do that and that costs a lot of money.”

Nemecek said dismissing the dimmers is a slippery slope to more hazards and problems in Kansas City.

“As a resident of Kansas City, I was driving home Saturday night down Barry Road, where they have 4000 Kelvin (K) lights and no dimmers,” Nemecek said. “The streets were wet and the glare was stunning.”

“You could just hardly — you were squinting at night driving through there.”

How lighting affects wildlife

The AMA’s statement points to the detrimental effects of high-intensity LED lighting on humans, but also various wildlife species.

“For instance, poorly designed LED lighting disorients some bird, insect, turtle, and fish species, and U.S. national parks have adopted optimal lighting designs and practices that minimize the effects of light pollution on the environment,” the AMA states.

Nemecek said even if research debunks blue light from having any negative impact on human health, it certainly has a negative impact on wildlife.

“People don’t realize if you just turn off your lights outside in the spring and fall, it can decrease (bird) collisions,” she said.

Data aggregated by BirdSafeKC, a group aimed at reducing bird collisions in the Kansas City metro, revealed over 300 bird carcasses were found outside downtown Kansas City structures during the 2021 spring migration season – more than any other migratory season in the past three years.

Data shows at least 883 birds died of building and window collisions in Kansas City between 2019 and 2021, but this figure is likely underestimated due to street-sweeping by the KC downtown Community Improvement District and by private contractors.

“Kansas City is really lucky because we live on a migratory flyway, and it’s great for tourism and it’s just wonderful to see all these birds coming through and we want them to,” DeAnn Gregory, Kansas City resident, chemist and retired environmental specialist, said. “This is one time we do want to be a flyover city.”

“We want them to just keep right on going and make their amazing journeys, and then live to tell about it, but we know when cities put in high intensity, high Kelvin street lights, it does attract more birds to the city, where there are more dangers.”

Birds aren’t the only species in danger.

A 2016 study conducted out of Maryland found that in the presence of artificial light, fireflies’ flashes decreased by almost 50% per minute.

Another 2016 study, conducted out of Virginia, found light pollution reduces flashing activities in a dark-active firefly species (Photuris versicolor) by 69.69% and courtship behavior and mating success in a twilight-active species (Photuris pyralis).”

In addition, street lighting strongly reduced the abundance of moth caterpillars, compared with unlit sites, and affected caterpillar development, according to a 2021 study published by Science Advances.

Nemecek said caterpillars make up a substantial portion of hatchlings’ diets, so less caterpillars equates to fewer birds capable of fully developing, migrating, and mating.

“I think that, regardless of your connection to wildlife and its migration and how lights impact it, or how much you think lights are going to impact, personally, your melatonin levels and your sleep, and that kind of thing – I think that there is this inheritance that we have of connection to the night sky, and I think that people should not underestimate that,” Nemecek said.

Vayu said city officials need “to find that sweet spot,” where everyone feels safe, everyone is actually safe, and the environment is not put in harm’s way.

“The city and the residents and everyone involved should ask the question, ‘What is the purpose of outdoor lighting?’ and ‘To meet or satisfy that purpose, what is the least intrusive way of doing that, given these other considerations, like human health, glare, animal, plant, environmental health?’” he said.