The American Medical Association issued a warning against the widespread use of blue-white rich, light-emitting diode (LED) technology. A recent press release issued by the health organization describes harmful effects to humans and wildlife as a result of exposure to high-intensity, cool light emitted from some LEDs. The introduction of inexpensive, energy efficient LED light has revolutionized the way we light up at night. As cities get on board to replace a century of incandescence, the AMA urges communities to improve outdoor lighting systems and adopt guidelines for doing so.
Blue-white light LEDs produce short wavelengths that are significantly brighter than the longer wavelengths of amber-colored bulbs. Studies show that glare from these lights suppresses melatonin, which hinders humans' ability to sleep, which can result in a spectrum of health-related issues such as obesity and stress related illnesses. Bright blue-white, outdoor lights also bring safety risks, and are detrimental to a variety of animals that depend on naturally dark environments.
Not all LEDs are created equal. Based on National Park Service (NPS) standards for optimal lighting designs, the AMA recommends using LEDs that emit the lowest levels of blue light, and fixtures that are shielded and direct light downward in order to reduce light pollution.
The NPS Natural Sounds and Night Skies Team has been on the leading edge of preservation of naturally dark night skies and environments in and around protected areas through the development of technology that more accurately assesses and predicts the effects of light pollution, and through collaborative research partnerships that advance our understanding of the ecological effects of light in naturally dark environments.