Outdoor Lighting That Lessens Light Pollution

Inappropriate nighttime lighting can negatively affect people and the environment.

By Leora Radetsky
From the February 2024 Issue


Since our ancestors lit the first campfires, illuminating the places where people live, work and play has been important to human communities all over the world. Now, most of the planet is awash with light day and night, a tacit feature of our 24/7 society.

Our assumptions about the value of light at night are changing, however, as research increasingly shows there are drawbacks of electric light at night. When exterior lighting is poorly selected, sited and/or installed, it contributes to light pollution that negatively affects people and the environment. Reported impacts include disorienting wildlife1 (nesting sea turtles and migrating birds, for example), hampering astronomical research, wasting energy, and contributing to greenhouse gas emissions.

Light Pollution
Research shows the drawbacks of electric light at night. (Photos: Adobe Stock/ lilyl)


Inappropriate nighttime lighting also negatively impacts human communities in various ways. For example, sky glow—the cumulative scattering of direct and reflected light across the night sky, now obscures the Milky Way2 from view for over a third of the world’s inhabitants, including 60% of Europeans and 80% of North Americans. And, rather than improving public safety, over lighting in historically marginalized communities3 is often driven by racial stereotypes and misinformation and has harmed the quality of life and well-being of neighborhood residents. A 2020 study4 found that Americans of Asian, Hispanic, or Black race/ethnicity were twice as likely as white Americans to experience “excessive exposure to ambient light at night…a documented hazard to human health.”

Inserting Outdoor LED Lights

Now, outdoor LED lighting offers many benefits over older lighting types, including improved energy efficiency, better optical control, and dimming capabilities. If not responsibly designed, however, today’s outdoor lighting projects could cause a suite of unintended consequences, including increased sky glow, light trespass, and glare.

One of the primary causes of light pollution is overlighting, above and beyond best practices for outdoor lighting. Since more light does not necessarily ensure safer spaces for people, the guiding principle for outdoor lighting projects should be to use only the right amount of light only when and where it’s needed. When people aren’t present, we should leverage controls and sensors to dim and switch off unnecessary lighting.

Light Pollution
Inappropriate nighttime lighting also negatively impacts human communities in various ways. (Photos: Adobe Stock/ Wolfilser)


Choosing lighting products that are controllable, dimmable, have color temperatures of 3000K or lower and minimize uplight provides a great baseline to mitigate light pollution. With these factors in mind, the DesignLights Consortium (DLC) launched its LUNA program in 2021. LUNA supports and promotes adoption of outdoor LED lighting that adheres to a science-based set of performance objectives shown to mitigate the impacts of light pollution. For lighting decision makers, the LUNA V1 Technical Requirements and accompanying Qualified Products List (QPL) streamline the process of selecting quality exterior lighting products that minimize sky glow and light trespass, while still providing appropriate illumination and yielding the efficiency and maintenance benefits of LED lighting.

Getting nighttime lighting right can be a challenge—but by implementing responsibly designed outdoor lighting solutions, facility managers can help people feel safer, without the negative impacts.

In addition to meeting independently vetted light pollution mitigation criteria, luminaires on the LUNA QPL meet all the DLC’s solid-state lighting thresholds for efficacy, quality, controllability and reliability. This makes them eligible for valuable rebates from the 75% of North American energy efficiency programs that require DLC-listed products.

Selecting products from the LUNA QPL can also help operators of commercial and industrial facilities stay inbounds of light pollution rules and ordinances adopted by an increasing number of municipalities and states. Hundreds5 of cities, towns and counties in the U.S. and Canada have enacted some type of light pollution law or ordinance, and 19 states, the District of Columbia and Puerto Rico have adopted laws to mitigate light pollution6. LUNA-listed products can also help decision makers certify compliance with light pollution criteria specified by rating systems such as WELL, LEED, and SITES.

Getting nighttime lighting right can be a challenge—but by implementing responsibly designed outdoor lighting solutions, facility managers can help people feel safer, without the negative impacts.

Light PollutionProtecting The Night For People And The Environment

Excessive and poorly controlled outdoor lighting can have detrimental effects on plants and animals, as well as people. Read more…








Light PollutionRadetsky is LUNA Program Director and Senior Lighting Scientist at the DesignLights Consortium (DLC). With over 20 years of experience in the lighting industry, Radetsky provides lighting science input for the DLC’s technical requirements. A recipient of an Illumination Engineering Society (IES) Regional Technical Award from the Northeast region, she is also Lighting Certified by the National Council on Qualifications for the Lighting Professions, and a member of IES and the American Society of Agricultural and Biological Engineers.

Do you have a comment? Share your thoughts in the Comments section below, or send an e-mail to the Editor at jen@groupc.com


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