September 4, 2023
This Texas Town has Reduced Light Pollution by 20%
The CBS News report above is 7minutes and 48 seconds long. If you’re a busy lighting person who can only spare a couple of minutes, start watching at the 5:00 mark.
“Light pollution is completely reversible. It's one of the few kinds of pollution that you could solve immediately…”
A recent CBS News report brought attention to the acceleration of light pollution and what a certain part of Texas is doing to address it. Recent studies published in Journal Science highlight that due to excessive light pollution from electric sources, the night sky brightness is increasing by 10% annually.
In a bid to combat this challenge, Alpine, Texas, has become an exemplar for other communities to follow. The city, known as a prime spot for star gazers and located near the McDonald Observatory, in far West Texas, has proactively addressed the issue by overhauling its lighting regulations.
Light pollution, primarily caused by excessive artificial lighting, brightens the sky, making it challenging to observe celestial bodies. Stephen Hummel, an astronomer at the McDonald Observatory, pointed out to CBS News that the rapid adoption of brighter, whiter LED street lights exacerbates the problem. While these LEDs are energy-efficient and cost-effective they are often applied in a way that scatters more light, causing a more significant "sky glow."
Alpine, Texas Takes Charge
Recognizing the value of its dark skies, both for astronomical research and tourism, Alpine made a bold move. In 2021, the city council unanimously passed an ordinance regulating outdoor lighting. According to Chris Rugia, the Director of Tourism for Alpine, the goal is to preserve the "product" – the experience of the pristine night sky.
Unlike many other communities’ lighting ordinances that focus on new installation and might grant immunity to already-installed fixtures, the Alpine, Texas ordinance is particularly rigorous. It mandates the replacement of all non-compliant fixtures within a 5-year window. After the clock runs out in 2026, non-compliant installations will be subject to a fine of up to $50 per day.
Lumen Restrictions: For non-residential developments, there's a lumens cap of 50,000 lumens per acre. In contrast, residential areas have a more stringent cap, limited to 25,000 lumens per acre.
Color Temperature Cap: The ordinance strictly caps the color temperature at 2,700 degrees Kelvin or lower. This temperature range typically produces a warm, amber hue, which has minimal blue light and is thus less disruptive to both human sleep cycles and wildlife habits.
Prevention of Light Trespass: All outdoor lighting installations must be designed such that every bit of light emitted by the fixture is projected below a horizontal plane that passes through the fixture's lowest light-emitting part. Fixtures must be aimed to ensure that the light source, or the bulb, isn't visible from off-site or neighboring properties.
While the task of convincing homeowners and businesses to adapt might be challenging, the significance of preserving the night sky and the benefits it offers to the community are deemed worth the effort.
Hummel, utilizing an all-sky photometer, has noted a remarkable 20% reduction in nighttime light pollution since 2020. His findings, as featured on CBS News, also indicate that the plan executed across the dark sky reserve in Texas is yielding positive results.
Notably, the issue isn't isolated to smaller communities. Major urban hubs, including Los Angeles, Chicago, Pittsburgh and Phoenix, are also recognizing the importance of addressing light pollution. These cities are in the process of transitioning to dark sky-friendly street lights.
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"The problem really isn't money, it isn't infrastructure – really, it's awareness. Light pollution is completely reversible. It's one of the few kinds of pollution that you could solve immediately if you wanted to. You could flip a switch and fix the problem." — Stephen Hummel, Astronomer |
