By Dorene Maniccia
Even people who are usually indifferent to stargazing couldn’t resist looking up last month following weeks of media buildup about the year’s best meteor shower, the Perseids, peaking August 11 and 12, 2021. Peppered among articles about how, where, and when to watch the shooting stars were other stories as well, however. Some doubted the ability to see the annual spectacle, blaming the increasing rarity of naturally dark skies that have enabled humans to connect with the universe for millennia.
Those lamenting that loss are not imagining or even exaggerating it, scientific research shows. According to an atlas of night sky brightness published in the journal Science Advances encompassing over 10 years of satellite data and 30,000 on-the-ground measurements, a third of all people on Earth, including nearly 80% of North Americans, now can’t see the Milky Way due to a rapid increase in artificial light at night.
Whether you’re an amateur astronomer or a business interested in conserving electricity and saving energy costs, light pollution is a relevant topic — and one with urgency, as research published in 2017 revealed artificially-lit outdoor areas are growing at an annual rate of 2.2% worldwide. While outdoor lighting clearly aids human safety and navigation, these benefits can come with costs. Claims of harm connected with artificial light at night range from disrupting human sleep patterns and disorienting migratory birds and sea turtles to hindering astronomical research and wasting electricity.
On the latter point, the National Conference of State Legislatures notes that “billions of dollars are spent in the U.S. each year to light our streets, shopping areas, office complexes, and sites used for energy development” but much is wasted “since many light fixtures are either poorly designed or emit light aimed in the wrong direction.” The International Dark Sky Association (IDA) reports that a third of all outdoor lighting in the U.S. is wasted — largely by unshielded fixtures, costing facility owners some $3.3 billion annually. And, the IDA points out, since wasted illumination derives from wasted energy generation, it is also responsible for 21 million tons of carbon emissions annually, making light pollution a factor in the climate crisis.
While the cost of wasted electricity is certainly an issue for those considering outdoor lighting projects, light pollution has other implications for facility owners and managers as well. Following the “triple bottom line” principle, many companies now consider not just financial profit, but also benefits to people and the planet when measuring success. Factors such as investment in environmental sustainability and wellness and consideration of employee workplace satisfaction have gained significance in terms of corporate standing, reputation, and employee recruitment and retention.
Consequently, it’s not surprising that the “green” building market is growing exponentially as employers and employees alike increasingly link sustainability features to job satisfaction and performance. Between 2006 and 2018, the number of Leadership in Energy and Environmental Design (LEED) certified buildings in the U.S. increased from 296 projects to 67,200. Among the aspects of a building project eligible for LEED certification points is light pollution reduction, with requirements intended “to increase night sky access, improve nighttime visibility and reduce the consequences of development for wildlife and people.” Similarly, consideration of artificial light at night counts toward the WELL Building Institute’s certification of spaces and communities that advance health and well-being. Both the Institute’s Building and Community Standards award points to projects that mitigate nighttime light pollution, with the organization maintaining that lighting “should be planned to maximize benefits and to reduce light pollution, light trespass and adverse health outcomes.”
Meanwhile, some government entities are moving to set clear parameters around the types of outdoor lighting facility developers can install within state and local boundaries. Nearly two dozen states have laws regulating outdoor light at night in some way, the most recent being a 2021 Nevada law championed by the state’s Division of Outdoor Recreation. Efforts are underway in a number of municipalities around the country, as well. Recent examples include proposed local ordinances in Washington and Missouri; provisions governing a streetlight project in Santa Fe, New Mexico; and a citizen advocacy movement on Nantucket (Massachusetts), where satellite data indicates light pollution has increased 22% in nine years.
In late August, Pittsburgh Mayor Bill Peduto announced a “Dark Sky Lighting” ordinance that would apply to newly installed or retrofitted streetlights and newly constructed and renovated parks, playgrounds, and municipal buildings. The Pittsburgh City Council is expected vote on the measure in early September.
“By introducing Dark Sky legislation, the city is further advancing its commitment to reduction of energy consumption, and elimination of waste in accordance with our Climate Action Plan goals,” Peduto said a news conference. “Our park spaces and city facilities should serve as the model for others to follow.”
LUNA Specs To Address Outdoor Lighting
An international non-profit whose mission encompasses both energy efficiency and the quality and controllability of lighting to benefit people and the environment, the DesignLights Consortium (DLC) is also working on this issue. Collaborating with electric utilities, as well as lighting manufacturers, industry stakeholders, and designers, the DLC establishes product quality and performance specifications that inform energy efficiency incentive programs that utilities offer to their commercial and industrial customers. Last year, we launched an effort to help mitigate the negative impacts of artificial light at night. Our new LUNA ( (Light Usage for Night Applications) specifications will supplement the DLC’s existing technical requirements for solid-state lighting (i.e., LED) luminaires, identifying energy efficient luminaires that also minimize light pollution, are controllable, provide appropriate visibility for people and limit negative impacts to the environment.
Currently undergoing a second round of review with an updated draft expected in mid-September, the DLC’s LUNA specification supports the Illuminating Engineering Society’s five principles for good outdoor lighting, recommending that lighting:
- Be installed only when and where there is a clear purpose;
- Be targeted, directing the light beam downward so it doesn’t spill beyond where it’s needed;
- Be no brighter than necessary;
- Be controlled with timers, motion detectors, and other technology that allows lights to be dimmed when possible and turned off when not needed; and
- Use warmer colors, limiting shorter (blue-violet) wavelengths shown to contribute most to light pollution.
The DLC anticipates finalizing the LUNA technical requirements by the end of the year, at which time manufacturers will be able to list and qualify their products to the specification. Lighting project designers will then be able to easily search for and select LED outdoor lighting products that are both energy efficient and have characteristics that enable best environmental practices for nighttime illumination.
Research continues to document the detrimental impacts that nighttime sky glow, light trespass and glare have on people and the environment. By reining in the use of unshielded, uncontrolled, excessive and poorly designed outdoor lighting, we can lessen these impacts while saving energy costs and carbon emissions.
Maniccia is the Director, Market Strategy and Development for the DesignLights Consortium (DLC). To learn more about light pollution, responsible outdoor lighting, and LUNA, please visit the DLC website at: https://www.designlights.org/our-work/luna.