Saving the night from light

Photo/Andrea Bugbee
Photo/Andrea Bugbee
A light with a simple shield over it remains useful and also helps to maintain a healthy outdoor nighttime environment.
A light with a simple shield over it remains useful and also helps to maintain a healthy outdoor nighttime environment.
Photo/James Lowenthal, Dept. of Astronomy, Smith College
Photo/James Lowenthal, Dept. of Astronomy, Smith College

For Going Green

How many humans does it take to change a light bulb? Well, that depends on how many recognize light pollution as a serious and growing problem.

According to Smith College Professor of Astronomy James Lowenthal, environmental issues associated with light pollution have been burgeoning in this millennium, thanks to population growth and the world’s hungry enthusiasm for LEDs.

“There’s nothing wrong with LEDs in general,” Mr. Lowenthal told a crowd of about 20 people gathered at the Platform Sports Bar in Northampton on June 13. He was speaking to members and guests of the Western Mass Green Consortium, a green living nonprofit founded in 2008 to promote sustainable building and life practices through local networking, collaboration, and education.

“There’s tremendous interest worldwide in LEDs saving energy use, but there’s pressure to bring the blue light down. Blue light is bad for wildlife. As many as a million birds are predicted to die each year due to blue light alone,” Lowenthal said. According to information from the International Dark-Sky Association (IDA), artificial lights disrupt not only migratory and night-hunting birds, but also sea turtles, frogs, bats, mice, zooplankton, coral, fireflies, and many other animals and insects.

Lowenthal said biological beings (including people!) depend on a 24-hour cycle of light and dark for crucial functions such as sleep, breeding, navigation, and avoiding predators. Insects, which are a food source to other animals and can act as pollinators for plants, are fatally drawn to bright lights, decreasing their numbers. Animals that navigate by moonlight are disoriented by bright, outdoor lighting and the massive “skyglow” emitted by cities into the atmosphere.

Skyglow, he said, also obscures the stars.

“Eighty per cent of people growing up today in America cannot see the Milky Way,” Lowenthal said. “This is a tragic loss. It’s a theft of nature.”

Modern LEDs have blue light values that mimic light from the sun. When the sun goes away, our bodies naturally produce the sleep hormone, melatonin. While all light suppresses melatonin, blue light amplifies this effect. It deceives our bodies into thinking it’s still daylight.

“Blue light at night is bad for your health,” Lowenthal said. “This is not a new thing. It’s been known for decades and decades. The CDC actually classifies shift work as a probable carcinogen.” Studies have linked prolonged blue light exposure to obesity, diabetes, disruption of sleep cycles, and some hormonally-related cancers.

Furthermore, light pollution, which Lowenthal defines as “excessive, unwanted, or overflowing light,” wastes energy. The IDA estimates that overlighting costs 3 billion dollars annually, and that 35 percent of all outdoor lighting is wasted simply because it isn’t directed correctly.

Why waste energy and money lighting the sky or woods around a parking lot instead of just lighting the parking lot itself?

To understand better, Lowenthal said, think of theater lighting. There, dozens of lights shine in different intensities, hues and directions. Everything the audience is supposed to see is clearly visible, yet none of the light spills to the audience, the sides of the stage, or the ceilings. “That’s what we should do outside as well,” Lowenthal said. “It’s exactly the same concept.”

If you’re someone who feels safer leaving your porch lights burning or keeping your business bright against vandals, you’re not alone. But, according to Lowenthal and the IDA, you’re not necessarily safer. Studies don’t conclusively prove that outdoor lighting prevents crime. Some suggest that bad lighting creates a false sense of security. And, on the roadside, it causes unsafe driving conditions.

For security, Lowenthal said, switch to motion sensor lights, lights on timers, lights with dimmers, or “smart” lights than can be adjusted remotely. And if your community is thinking of investing in an LED switchover, actively educate local administrators about low blue light and dark-sky-friendly choices.

“LEDs last for typically 20 years. Of course, the problem is if you make the wrong choice, you’re going to be stuck with it for 20 years,” Lowenthal said. “I think it comes down to this: We don’t need more lighting, we need better light. We need light that’s more controlled.”

Still in the dark about what action to take? The solutions aren’t out of reach.

First, when buying LEDs, choose those that burn at 3,000 or 2,700 kelvin. These emit the least amount of blue light. Next, choose lights that are no brighter than you need – glare is ugly, it wastes energy, and it actually makes it harder to see. Use timers and motion sensors whenever possible, and choose fixtures with lids and shields that direct light purposefully rather than letting it shine willy-nilly.

For specific lighting options, pull down on the “Find Dark Sky Friendly Lighting” tab on the IDA home page at

“Start with your own house. Start with your neighbors. Start with your own communities and city councilors,” Lowenthal said. Before long, you might become an activist like Professor Lowenthal himself. He regularly approaches businesses with bad lighting and offers to correct their fixture angles for a darker sky.

“Just ask,” Lowenthal said with a shrug and a smile. “Offer to show up with your ladder.”

That’s what he does.

Five Dim Ideas

1) Choose LED bulbs that burn at 3,000 or 2,700 kelvin. These emit the least amount of blue light.

2) Use bulbs that are no brighter than you need. Glare is ugly, and it makes everything harder to see.

3) Install timers and motion sensors whenever possible

4) Choose fixtures with lids and shields that direct light rather than letting it flood an entire area.

5) For light-conserving products, search the “Find Dark Sky Friendly Lighting” tab on the International Dark-Sky Association home page at


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