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MACOG Promotes Responsible Outdoor Lighting

Five principles of responsible outdoor lighting should guide replacement and new installations of outdoor lighting. The Michiana Area Council of Governments (MACOG) introduced the guidelines to its Partners for Clean Air at its 2023 Annual Awards Luncheon. The recommended practices encourage projects of all scales to use lighting that is useful, targeted, no brighter than necessary, controlled, and warm colors.

Presenting at the event, I opened with three aspects of light pollution, which is essentially errant and excessive light. Glare, which can be disabling, is light from the luminaire that shines directly into your eyes. Its effects are amplified with the ageing eye. Light trespass is spillover light that extends beyond the intended target and crosses boundaries or property lines. Sky glow is a light sheen across the sky caused from light bouncing off aerosols and small particulate matter, much of which is man-made. The background light washes out the night sky. All three effects impinge on humans and the entire natural order.

Excessive and errant light washes out the night sky and shines directly into the eyes.

Clean air advocates and dark sky advocates have many interests in common. Both seek to lessen the amount of energy consumption from carbon-based energy sources. With solid state technology, such as LED light fixtures and controls, everyone can now readily lessen air pollution and light pollution by following the five principles, which were published jointly by the International Dark-Sky Association and the Illuminating Engineering Society.

When installing lights, whether a single fixture at home or street lighting across an entire municipality, ask five questions.

  1. Is it useful? Much light is functionally unnecessary, such as architectural wall wash or uplighting trees. Perhaps it is time to consider whether uplighting flags all through the night is appropriate, and whether Sections 6a and 8c of US Flag Code should be deleted.

  2. Is it targeted? Lights should be fully shielded and aimed so no light goes above the horizon. A sag lens that extends below the light fixture defeats the purpose and should always be avoided.

  3. Is the light level low yet sufficient ? With LEDs there is peril with the promise of energy savings. Since LEDs are so much more efficient than incandescent lights, people then tend to install more lights while justifying the savings they still realize. This rebound effect cancels out the gains made by the improved technology.

  4. Is it controlled? Old-school technology still has a place. Simple motion detectors and dimmer switches start the savings and pollution reduction instantly. Meanwhile, modern solid state technology permits the system-wide control of the level of brightness, the time of illumination, and the color of the light output.

  5. Is the color toward the warmer colors? LED lights are rated by color, as indicated by the Correlated Color Temperature (CCT) in degrees Kelvin. Blue-rich lights, such as 4000K and 5000K, put out light in the color of the spectrum that affects the human circadian system. That blue is in the same wavelength as our body's peak circadian sensitivity. Avoid the blues! Use lights rated 3000K or less.

We can try to change human behavior to lessen wasted outdoor lighting. That has its limits, so we apply technologies to deliver results. A third means to lessen sky glow is to improve the medium through which the light travels so that there is less matter scattering the light. That is, clean the air itself.

A 2021 scientific studey confirmed the apparent--"air pollution mitigation can reduce the brightness of the night sky." The MACOG Partners for Clean Air are contributing to the improvement of the night sky with their efforts to improve the quality of the air. For that I say, "Thank you!" Your advocacy for clean air directly supports dark skies.

Lastly, I encourage everyone to have a visceral experience under a truly dark sky. Just as deep breaths of fresh mountain air are motivating to clean air enthusiasts, seek out a Genesis night. Find a place less impaired by light pollution and, as Walt Whitman wrote, "Look up in perfect silence at the stars."


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