This petition represents Arizonans in support of warmer LED lighting, and its benefits over cooler, whiter lighting.

As LEDs have become an increasingly cheap and energy-efficient option, cities have begun to replace older, existing lighting with this new technology. While we wholeheartedly support the transition to cheaper, more energy-efficient city lighting, these high-temperature LEDs raise some significant concerns. Fortunately, the benefits of LED technology need not conflict with our lighting needs.

Kelvin (K) is a measurement of a light's color (warm / cool light), while lumens are a measurement of a light's brightness. An LED light can be any of a wide range of temperatures or lumens. Because of this, it is possible to maintain a light's brightness and function, while improving its color.

Higher-temperature (bluer) LEDs have a number of harmful effects. Scientists with Harvard and the American Medical Association have voiced concerns regarding bluer lighting, noting that lighting from sources such as high-temperature LEDs reduces the body's ability to produce melatonin, an important hormone for sleep regulation. They have even raised concerns that this type of lighting may increase a person's chance of developing cancer, diabetes, heart disease, and obesity. Warmer lighting does not have this effect, and may allow us to sleep better.

In addition to the health concerns surrounding cooler LED lighting, there are also visibility concerns. As many have already noticed in cities across our state, bluer lights produce significantly more local glare. Drivers may now find themselves less able to see the darker areas of a road or sidewalk, which poses a major safety hazard, contrary to their purpose. Warmer lighting would reduce this glare, and may improve our driving night-vision.

Beyond important safety and health concerns, whiter lights wash out a valuable southwestern resource: clear skies. The southwest is a popular destination for stargazing and astrophotography for a reason: our skies are clear and our cities are surrounded by beautiful wilderness areas. In recent years, however, visitors and locals alike have had to travel farther and farther from cities like Phoenix to find the same clarity that once existed. For example, when lights of temperature 4000K replaced warmer, low-pressure sodium (LPS) lighting in the city of Flagstaff, Arizona, residents experienced a nearly 50% reduction in the number of visible stars due to the increased light pollution in their night sky. Warmer lights have a clear and significant positive impact on the ability of Arizonans to connect with the sky above us. Committing to warmer lighting could play a major role in how we perceive the universe and our place in it.

For the reasons above, and others not included, lighting in Arizona cities should be replaced only by warm-colored LEDs, preferably NBA-LED or PCA-LED. If cost prohibitive, LEDs 2400K or lower should be used with blue-light filters, though the small additional cost has been well worth it to many communities (Flagstaff, Sedona, Coconino County), once the benefits have been explained. By doing so, we will not only use less energy on a city- or state-wide level, but will also assist in ensuring a safer, cheaper, and healthier future for the southwest.