There is a ‘blue light epidemic’ that has infiltrated outdoor environments around the globe, all through a growing prevalence of more efficient LED lighting.
It started as a noble push to replace older, less efficient sodium lamps in streetlights, but the fixtures that have replaced them are now brighter, colder, more intense. These newer LEDs mimic that of mid-day sunlight because that’s the light humans see best under while also being the cheapest types of LED to manufacture.
This simple color shift—alongside one other behavioral quirk related to the implementation of LEDs—is, according to the University of Exeter, a major issue with concerns environmental and human health. Led by Alejandro Sánchez de Miguel the team of academics recently published their studies looking into the effects of artificial lighting designs on suppression of melatonin, visibility of stars in the sky, the altered responses of moths and other insects and the behavior of bats.
But if this all sounds like a story you’ve heard before, you’re not alone. It’s a conversation that’s been going on for a while in the built environment about how interior lighting can affect occupants, and it’s also why many lighting manufacturers are now developing circadian lighting or human-centric lighting options.
So, the question is, why aren’t we pushing for similar solutions for lighting the urban environment?
Blue Light in the Environment Impacts Far More Than Human Behavior
Blue light can wreak havoc on circadian rhythms when it appears when it shouldn’t. As one study found out, even brief exposure to bright, cool color temperatures halts melatonin production in humans for multiple hours after exposure.
In the Exeter study, the researchers found that the current style of LED streets triggers a circadian response five times greater than the old sodium lights. This melatonin suppression has also been on a steady rise in Europe since 2012.
For nocturnal animals, the lights can even interfere with their movement patterns. Insects like moths struggle and become drawn to bright lights, interfering with their life cycles, which can potentially lead to dwindling populations, leading to greater disruptions in local ecosystems where moths may be a prominent food source. The geographic range of bats also shrank in response to blue light’s presence in the environment.
There is also concern over the degradation of night sky visibility, though, this has less to do with blue light, and more how we choose to use LEDs currently. According to an article on TreeHugger, the findings over at Exeter seem to confirm a habit of use known as the ‘rebound effect’ wherein greater efficiencies lead to greater demand and greater use of a product.
As it turns out, the team at Exeter found that usage of LEDs has risen with efficiencies, and as a result, the night sky visibility in Europe has slowly been shrinking. More than an impact health-wise, the loss of the night sky has been keenly felt as a loss of connection with nature and the greater universe.
Outdoor LEDs Have the Power to be Better, Smarter
The incredible, and most fortunate, part about hearing this is that solutions do exist. More than that: they are being used, discussed and innovated upon constantly, just not in outdoor lighting.
Color-tunable, dimmable LEDs make up a significant portion of interior lighting today and are the backbone of circadian lighting systems. In a way, this makes those currently working on creating better indoor environments the best suited to assist in developing these better exterior solutions, at least when it comes to lighting. The lessons learned in creating beneficial lighting designs indoors can certainly help inform those working outdoors.
In the Dutch town of Nieuwkoop, Signify has deployed a series of outdoor luminaries that are touted as being ‘bat-friendly’ due to their use of red wavelengths. While readily visible to humans, it’s uncertain whether bats can even see red lights, but, if they can, it has been shown to have zero impact on their natural behavior. Red light also has little to no impact on human circadian rhythm when used at night.
Cumbria, England, renowned for having some of the darkest skies on the planet, has instituted its own special set of luminaries by Thorn to help maintain that distinction. These lights are shielded to prevent spillover, have reduced intensity and a warmer color temperature that dims deeper into the night.
It’s just ironic that indoor lighting was the first to start following the rules of the sun. Perhaps it’s because we’re aware of the detachment more. Regardless, all the innovation means that there is already a pool of professionals and products well equipped to solve the current issue.
Who knows? We’re probably not too far off from having smart exterior lighting that can adjust and dim like its interior counterpart. The technology is there: all it takes is someone to implement it at this point.