A non-LED streetlight, left, stands in the 1600 block of Matthew Terrace, and an LED streetlight, right, stands in the 1600 block of Lindenwood Lane.

The nighttime glow over Lawrence is growing.

Thousands of the city’s streetlights are being changed to a type of high-efficiency LED that some towns have begun avoiding for environmental and health reasons, and one group wants Lawrence to do the same.

Adrian Melott, emeritus professor in the department of physics and astronomy at the University of Kansas, said the negative effects of the type of LED streetlights the city is using — white with unseen blue light — are well established.

“There are literally hundreds of papers about the medical and biological effects of blue light at night on humans and animals,” Melott said.

Melott is a member the Lawrence Alliance for Responsible Lighting, which is asking the city to switch to LED colors and installation methods that preserve the dark night sky and are less disruptive. Some studies have shown nighttime exposure to blue light, specifically light with a color temperature higher than 3,000 kelvins, disrupts human sleep and disorients some animal species. Westar Energy is in charge of the majority of the city’s streetlights, and officials say their choice of LED bulb is the industry standard and the safest option for the city.

Sky-glow

Increasing sky-glow is a global trend. A five-year study published last month in Science Advances found that the planet’s light pollution has been steadily increasing. Satellite observations — which can’t detect the blue-rich light of some LEDs — still show that nighttime brightness from artificial light grew by about 2 percent each year from 2012 to 2016.

Color temperature is a reference to the appearance of the light, but blue-rich LED lights are also some of the most efficient LEDs, enabling them to emit more light with less energy.

Westar Energy operates 3,500 streetlights in Lawrence, more than half of which are already equipped with blue-rich LED lights with a color temperature of 4,000 kelvins, according to Westar officials. Westar spokeswoman Gina Penzig said Westar adopted 4,000 K LEDs in 2015 and has been installing them as old streetlights burn out.

Penzig said that type of LED light provides increased visibility and safety, and it is advantageous for law enforcement because it reveals truer colors, which is important for vehicle descriptions. She said 4,000 K LEDs are the standard for the lighting industry.

“Right now we are just staying consistent with the industry standard,” Penzig said.

The Lawrence Alliance for Responsible Lighting has requested that Westar and the city begin using LEDs with softer colors and lower intensity, and that are equipped with shielding that directs the light downward — away from the sky and homes. Specifically, the group wants the city to follow recommendations from medical and biological groups that LED lights have color temperatures below 3,000 kelvins.

“We’d like them to use a light color that you might call soft white rather than bright daylight for any outdoor use,” Melott said. “And then consider where the light is going. For a streetlight, you want the light to go down onto the street — that’s where you need it.”

The group’s request isn’t novel. As light pollution has increased, so has the effort to preserve the nighttime environment, both to ensure the visibility of stars and for the health of humans and animals.

The International Dark-Sky Association has set parameters for outside LED lighting — including that lights be shielded and have color temperatures below 3,000 kelvins — and there is a list of places that pride themselves on being official “dark sky” locations. Those include cities such as Flagstaff, Ariz. and Horseshoe Bay, Texas, as well as some parks and reserves.

Complaints

Some neighbors have noticed the changeover from the old, non-LED streetlight bulbs, which emit a softer yellow light. Ted Boyle, president of the North Lawrence Improvement Association, said he’s been getting complaints from neighbors as soon as the new LED streetlights go in.

“Like 24-hour daylight,” Boyle said. “They were so bright that they would shine in people’s windows, and people couldn’t sit out on their front porches because it was so bright and glary.”

Boyle said many of the neighbors prefer the golden color of the old lights, which he said are more inviting and not hard on the eyes. He said he’s been handling calls to Westar on behalf of neighbors when the new LEDs go in, and that Westar technicians have done a good job of adjusting the lights accordingly.

Penzig said Westar has gotten about a dozen complaints in the past year about LED streetlights in Lawrence neighborhoods. She said the structure of the streetlight itself already helps prevent light from shooting upward, but when complaints are received, technicians can adjust the brightness and add additional shielding to better direct the light downward.

“One of the advantages that LEDs offer is you are better able to control the direction of the light so that you are really focused on those areas where that light is useful,” Penzig said. “So it does help decrease light pollution.”

Penzig also said Westar is definitely watching developments and discussions regarding sky-glow and wants to fix issues of excess light. She said if the new streetlight LEDs are providing unwanted light in certain areas, residents can call Westar’s customer service line to have the light shielded or dimmed.

Medical recommendation

Members of the Lawrence Alliance for Responsible Lighting also note that the quality of the blue-rich light is harsher but warn that the issue goes beyond aesthetics.

Some studies have found nighttime exposure to blue-rich light is hazardous because it creates glare for drivers, disrupts human sleep patterns and disorients some migratory and nocturnal animals.

Last summer, the American Medical Association issued guidelines based on the research on blue light, and advised against the installation of blue-rich LED streetlights. The AMA states that blue-rich LED streetlights have five times greater impact on circadian sleep rhythms than conventional streetlights. It recommends that communities minimize blue-rich streetlights and generally use LEDs no brighter than 3,000 kelvins.

Some cities have followed the AMA recommendation. For instance, Prairie Village recently piloted 4,000 K LEDs and ended up going with 3,000 K instead. That decision was driven by the AMA recommendation, according to the Shawnee Mission Post.

Disagreement from the lighting industry

Westar and the lighting industry, however, have a different view.

Critics of the AMA recommendation, including the Department of Energy, point out that the guidelines don’t specify exactly how much blue light exposure is harmful. They also note that computers, smartphones and other devices emit blue light at much higher levels.

Westar installs the streetlights and the city pays a flat rate per pole for the electricity and maintenance, according to Public Works Director Chuck Soules. The city also owns about 800 street, pedestrian or parking lot lights, and decided to use 4,000 K LEDs in those fixtures before the publication of the AMA guidelines.

The city previously defended that choice, and Soules said that position has not changed. The city has put together an online report that explains its decision, stating in part that the transportation system is the key consideration and that the 4,000 K lights provide better visibility and safety for drivers and pedestrians.

Going forward

Melott said he sees a difference between public outdoor lighting and personal devices, which have settings that can switch a screen’s light to a yellow color after sunset. He said he doesn’t understand why those in the lighting industry won’t follow the AMA guidelines.

“I’ve seen a tendency on the part of some people, when it comes to biological or medical effects, to consider the opinions of electricians and engineers as of equal weight to those of biologists and doctors,” Melott said. “I don’t understand why anyone would do that.”

So far, though, the group’s efforts to reduce the city’s blue light have been unsuccessful. The group has spoken with both Westar and the city, and the city is preparing to deny the group’s request that Lawrence adopt an ordinance that outdoor lights be lower than 3,000 kelvins.

Soules said city staff considered the group’s request, but no changes are being made at this time. Staff’s recommendation to maintain 4,000 K LED streetlights will be provided to the City Commission during the commission’s Tuesday meeting as part of the city manager’s report.

When asked what it would take for Westar to reverse course and begin using 3,000 kelvin LEDs, Penzig said the collective research would have to reach a consensus. She said she hopes that some of the groups with differing viewpoints or approaches to the issue would join in a study together to help reach a more certain outcome.

“If that collective research really started to come together and provide us conclusive information that a different color temperature was the best for lighting communities, then we would be compelled to look at that and consider a change,” Penzig said.