More than 80 years ago, Aldous Huxley imagined night in his Brave New World: “almost without clouds, moonless and starry; but … the electric sky-signs effectively shut off the outer darkness.” While his words described a dystopian London in 2540, they might also paint where we are headed. Already awash in artificial light, cities everywhere have begun to embrace LED technology, which too often brings dangerous levels and types of lighting. Now, in St. Paul and in Minneapolis, we have an important decision to make about which LED streetlight will light our nights (“LED streetlight change puts cities in new (harsher?) light,” July 17).
For several years, I have been traveling the country to discuss the ways we can light our nights more intelligently, thoughtfully and responsibly. While LEDs have great promise in terms of energy efficiency and cost savings, too often the perils of LED street-lighting are less understood. In some cities, including St. Paul and Minneapolis, the potential impacts to human health of these lights have given pause to their installation.
This is wise. Before we sign off on the current move to retrofit our streetlights with intensely bright blue-white LEDs, we should be clear about the impact.
First, increasing numbers of studies argue that these lights negatively affect human health. One result, as the Star Tribune reported, is that the American Medical Association recently warned cities against installing LEDs with color temperatures of 4,000 (or more) degrees Kelvin. This type of LED casts a harsh glare heavy with the blue-rich “white” light that wide-ranging research has shown contributes to sleep disorders, confuses our circadian rhythms, and — by disruption of our body’s production of the hormone melatonin — increases risks for breast and prostate cancer. In fact, the World Health Organization considers working the night shift a “probable carcinogen,” equivalent in effect to breathing diesel fumes.
Next, we aren’t the only species affected by these lights. I sometimes hear people say: “Just buy shades for your windows.” But no other creature has the luxury. More than 60 percent of invertebrates and 30 percent of vertebrate species are nocturnal, with many more active at dawn and dusk. Many of these species are the insects that pollinate the flowers and plants we enjoy and that provide the protein foundation for entire ecosystems. Artificial light at night destroys their habitat, and the new “blue” LEDs are the most destructive.
Third, these brighter lights will not increase our safety. In fact, while some light at night can indeed help increase our safety by improving our vision, too much light — or light that is too bright — actually can reduce safety. Recent research has shown that we see best at night by contrast, by having lighted objects stand out against a dark background — a green highway sign lit by headlights, for example — rather than by lighting everything as brightly as possible. In fact, in trying to light up the night, we create glare and cast shadows that actually make it more difficult to see, and thus decrease safety for motorists, cyclists and pedestrians alike.
Remarkably, future recommendations for safety actually will call for less light. The Illuminating Engineering Society, the organization most responsible for recommending lighting levels in the U.S., already has begun to adjust its standards for street lighting accordingly.
Finally, the switch from electric light to electronic light offers an opportunity to rethink the way we light our nights. Installing the cheapest and brightest blue-rich white LEDs represents a continuation of our costly and wasteful habits. Simply put, we use far more light than we need, and we use it in ways that endanger our health and the health of the ecosystems on which we rely; waste energy and money, and rob us of the night sky. This is light pollution, an almost wholly unnecessary condition we could solve by making relatively simple choices.
Thankfully, here in the Twin Cities, we have such a choice. We need not install LED streetlights that shed dangerous and ugly light. LED lamps rated 3200K or 3000K would meet our every demand for street lighting without incurring such dramatic costs.
I urge my fellow Minnesotans to ask their local officials to choose lamps rated at this lower level, and I would urge this action soon. LED streetlamps are designed to last for decades, and so the decision we make now will reverberate far into the future. Let us choose wisely.
Paul Bogard, of Minneapolis, is the author of “The End of Night: Searching for Natural Darkness in an Age of Artificial Light.”