How DarkSky Standards Combat Light Pollution and Protect the Night Sky

This story was originally published by  Diana Kightlinger on the Bluebeam Blog.

DarkSky International, an education, advocacy and conservation organization protecting the night sky, approves new luminary standards, lighting programs and policy language

At one time, nightfall plunged our ancestors into darkness and let them marvel at celestial objects in an inky sky. But in recent times, our ability to alter natural light levels has advanced to the point that stars, planets and galaxies are fading from view. Of the 2,500 stars that should be visible, the typical American suburbanite can see only a few hundred.

Instead of starlight, the night is filled with streetlights, spotlights, stadium lights, neon signs, billboards and parking lot towers—all contributing to light pollution, defined by National Geographic as the excessive or inappropriate use of outdoor light. Light pollution damages human health, alters wildlife behavior and wastes energy and money as light blazes when and where it’s not needed. The result is glare that blinds drivers, light trespass that disturbs sleep, eerie orange skyglow over metro areas and confusing and garish groupings reminiscent of Times Square.

Until light is policed in the same way as air, water and land pollution, it falls to architects, engineers and designers to select lighting systems that perform their function while still preserving the night sky—with the help of manufacturers whose fixtures meet the specs for responsible lighting and governments that support policies to protect darkness.

“I think people are understanding the urgency of lighting design, because it’s become more and more difficult to see a clear night sky from anywhere,” said James Brigagliano, lighting program manager at DarkSky International.

The harmful effects of too much light

Light where it doesn’t belong disrupts the night and day rhythm encoded in the DNA of all animals and plants. That impacts behaviors from feeding and sleep to reproducing and evading predators.

Human circadian rhythms are attuned to outdoor light during the day and darkness at night. Breaking that cycle with artificial light increases the risk for obesity, depression, sleep disorders, diabetes and other diseases, according to research reported in Environmental Health Perspectives.

For wildlife, prey use darkness as cover and predators use light to hunt, so illumination dramatically alters the environment and the odds. For instance, newborn sea turtles need to turn toward the ocean and safety after hatching on the beach, but often they’re confounded by light on shore. Birds that migrate or hunt at night are lured by brightly lit cities and veer from their flight patterns. And after dark, the insects that birds depend on are drawn to burning bulbs and their deadly heat.

Worse still, lights are often pointless, adding economic waste to ecosystem harm. DarkSky International estimates that at least 30% of all outdoor lighting in the United States serves no purpose and is emitted by lights that don’t have shields to prevent spillage. Wasting light costs $33 billion each year and uses about 120 terawatt-hours of energy—enough to meet New York City’s electricity needs for two years. Quality outdoor lighting could cut energy use by 60% to 70%, saving billions of dollars and reducing carbon emissions. But that depends on lighting responsibly.

Five principles for responsible outdoor lighting

DarkSky and the Illuminating Engineering Society jointly published the Five Principles for Responsible Outdoor Lighting to prevent and reduce light pollution. Designing new projects or retrofits using the principles can create beautiful, functional, healthy lighting that minimizes harmful effects and saves energy and money.

1. Useful: If it’s not serving a function, you shouldn’t have it.

Identify the purpose of lighting and its impact on everything in the vicinity, including wildlife and habitats.

• Targeted: Aim light so it falls only where it’s needed.

Direct and shield light beams so they point down and don’t spill outside the area being lit.

• Low level: Light should be no brighter than necessary.

Use only the light required and make sure nearby surfaces don’t reflect light and create excess.

• Controlled: Use light only when it’s needed.

Install motion detectors, dimmers and timers to allow only the minimum light needed available at any time.

• Warm-colored: Use warmer-color lights where possible.

Cut back on shorter wavelength light (blue-violet) to the least amount needed.

New standards, programs and policies to bring back the night

The DarkSky Approved program provides objective, third-party certification for lighting design,  products and installed projects that reduce light pollution. Designers can search products by manufacturer, use, retailer, light temperature and residential use. Project standards fulfill requirements for Leadership in Energy and Environmental Design (LEED) certification as well, but requirements continually evolve based on new information.

“We’re cutting down on what we allow for high-angle lighting—from 90 to 80 degrees,” Brigagliano said. “So now we’re allowing only 1% of the total light output of a fixture to be between 80 and 180 degrees. There’s no benefit to light between 80 to 90 degrees and the new cutoff will help reduce uplight and sky glow.”

DarkSky Approved programs now include pedestrian lighting as well as sea turtles, sports venues and lodging. The new program addresses glare from light fixtures used in areas like campuses where people need lower-level lighting for safety at night.

“We also have wildlife-tuned luminaries, with subcategories like sea turtles,” Brigagliano said. “That’s needed because different species have different sensitivities to wavelengths. However, if we control brightness and shield the light source, we’ve taken care of much of the issue and the color of light is less important.”

In addition, DarkSky recently released an updated and simplified model policy that was written to make it easy for states and municipalities to adopt. “Just a little bit of improvement is better than none,” Brigagliano noted.

Every place a dark sky place

The International Dark Sky Places program certifies areas worldwide that preserve and protect darkness through responsible lighting policies and public education. Not all are remote parks and sanctuaries—a neighborhood or city can earn recognition as a Dark Sky Community or Urban Night Sky Place if residents are committed to a healthful and beautiful night.

“Anywhere where there’s a DarkSky-approved place, there’s been a fair amount of dark sky conceptual lighting design,” Brigagliano said. That work may soon be required as part of state or local regulations. At least 19 states and a number of municipalities have laws in place to reduce light pollution.

To be ready, architects, engineers and designers must recognize that light can be a pollutant—and balance providing light with protecting the dark.

Hero image courtesy Mark Eichenberger