Exterior Lighting

Responsible Outdoor Lighting

Light pollution - the human-made alteration of outdoor light levels from those occurring naturally at night – can be as irritating as noise pollution is for neighbors!

It has been accelerating since the advent of electrical lighting 150 years ago, and, worldwide, increased at an alarming 10% per year from 2011 to 2022 according to an authoritative study published in 2023. Since LED fixtures and bulbs reduce energy use compared with older technologies, they are so inexpensive to operate that the temptation is to increase outdoor lighting without thinking through the consequences. LEDs have also introduced a new problem: too much light in the blue end of the light spectrum. Blue light scatters in the atmosphere much more than other colors of the spectrum and, for most people, feels harsh at night and is blinding. It also has more negative impacts on wildlife than warmer colors.

Houses of Worship (HOWs) started lighting steeples and bell towers in the 1950s as local landmark-lighting or to communicate the idea of a beacon. Like many other businesses, they light up signs and have also installed parking lot lighting for evening activity safety reasons. And many times, fear of break-ins has drawn them into using "security lighting" left on all night long. Unfortunately, poorly designed parking lot and security lighting, and the uplighting of architectural features and façades, often causes conflict with residential neighbors. It also has negative impacts on human health and safety, our environment and even our spirituality.

Negative impacts of light pollution on Creation:

• ‍Energy and Climate Change: light going up and out from a fixture instead of down where it is needed wastes money and energy, and it damages the climate through unnecessary emissions.‍
• Human health: Research suggests that artificial light at night, especially blue light content, can negatively affect human health by disrupting the cycles of the key sleep hormone, melatonin, resulting in increased risks for obesity, depression, sleep disorders, diabetes, breast cancer, and more.‍
• Crime and safety: There is no clear evidence that increased outdoor lighting deters crimes. And glare can keep you from seeing an intruder or a pedestrian.‍
• Wildlife and ecosystems: Light pollution harms our fellow beings. For billions of years, all life has relied on Earth's predictable rhythm of day and night. Humans have radically disrupted this cycle by lighting up the night.‍
• Night sky heritage: The natural night sky is our common and universal heritage, yet it's rapidly becoming unknown to the newest generations, as the glow of uncontrolled outdoor lighting has hidden the stars and changed our perception of the night. A starry sky has traditionally been a source of awe and spiritual connection to the universe, and natural sky darkness at night is the yang to the ying of day.

Light pollution takes four forms:

• Sky glow: brightening of the night sky over inhabited areas (top of diagram at left)
• Light trespass: light falling where it is not intended or needed, such as in neighbors' windows
• Glare: excessive brightness that causes visual discomfort, especially for older folks
• Clutter: bright, confusing, and excessive groupings of light sources

Useful lighting ("area to be lit" to the left) is that which illuminates the ground as needed for human safety.

Stewardship Opportunity Solutions:

Responsible outdoor lighting seeks to meet the needs of people to see at night while conserving energy, avoiding harmful effects on humans and wildlife, and protecting our night sky.

The Five Principles for Responsible Outdoor Lighting have been developed by DarkSky International and the Illuminating Engineering Society (IES). Outdoor lighting should be:

• Useful: have a clear purpose.
• Targeted: directed downward using shielding so the light emitted falls only into the space where it is needed.
• Low Level: use the lowest amount of light that meets the purpose.
• Controlled: use timers, motion detectors and dimmers.
• Warm color temperature: An LED rating of 1800-2700K is much less detrimental due to lowered blue-spectral content.

By applying the five principles to our houses of worship, we can set an example to the community - our religious one and the larger ones around us.

Often, cities and towns in Massachusetts have lighting ordinances, general by-laws, zoning by-laws or both, which somewhat reflect these sensible guidelines. To see if yours does and what it entails, see the DarkSky Mass webpage on ordinances.

Application: How to find dark sky compliant fixtures and bulbs

With the basic principles outlined above, the next question is finding lighting that adheres to them.

• ‍Fixtures: DarkSky International has a light fixture certification process resulting in a searchable online database. The graphic on the next page contrasts some examples of compliant and non-compliant lighting.

• ‍Light sources: Once a HOW has chosen a compliant fixture, attention must then be paid to the brightness and color temperature of the light source itself.

Brightness, or intensity, is measured in lumens. Use the fewest lumens that do the job. A shielded fixture will require a bulb rated about 50% lower in lumens for the same amount of light hitting the ground than needed in an unshielded fixture. See this DarkSky Mass web page for recommendations on brightness levels for different situations.

Newer lighting fixtures with a built-in bulb often have an adjustable light color temperature. Use the warmest color (that is, lowest temperature) setting, being sure 2700K or less is available. "Amber" implies 1800-2200K and is similar to the bug lights of the past.

If the fixture is designed for a replaceable bulb, carefully read the label on the bulb package to choose one which is 2700K or less in color temperature and of appropriate brightness for the task.

Controls: Motion detectors, timers and/or dimmers are electronic devices that can minimize outdoor light usage to only the time and the intensity needed. Some bulbs have motion detectors built into them. Timers and dimmers are usually integrated into a switch or a control system.

Before and After Example – St Patrick's Church, Newport, Co. Mayo, Ireland:

Resources:

• DarkSky Massachusetts: darkskymass.org
• DarkSky International: www.darksky.org
• www.lightollutionmap.info (VIIRS) (zoom in on your town or city's light pollution in different years)
• www.lightjustice.org (based in Cambridge, MA, addresses light pollution in environmental/social justice communities)‍
• globeatnight.org (citizen scientist night sky observations)
• The End of Night – Paul Bogard (chapter 4 concerns the spirituality of the night sky)
• The Darkness Manifesto - Johan Eklof (example of steeple lighting negatively impacting Creation)
  Learning to Walk in the Dark - Barbara Brown Taylor (spirituality of darkness)

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