Lighting Codes
The installation of LED street lighting is growing in popularity due to its lower operational cost and bright light. However, concerns have been raised regarding the health impact of certain types of LED lighting, specifically those emitting blue-white light that mimics daylight.
According to the American Medical Association (AMA), LED streetlights with higher levels of blue-white light can suppress melatonin production during the night, negatively impacting the body’s circadian rhythm and leading to reduced and poorer quality sleep, excessive sleepiness during the day and reduced attention spans. Chronic exposure to harsh, blue-white light, which reaches deep into the eye, is associated with retinal cell damage, cataract formation and age-related macular degeneration (AMD).
Street lighting at UC Davis, courtesy of the California Lighting Technology Center.
LED lights come in a range of colors, from those that mimic full-spectrum daylight to those that closely resemble the warmer glow of an incandescent bulb. The color temperature (warmth or coolness) of a light source is measured in degrees of Kelvin (K) on a scale from 1000K to 10,000K. At the higher end of the scale (5000K-6500K), LED bulbs mimic daylight and have a harsher, blue-white appearance. LED bulbs 2700K or below have an orange-yellow warmer glow.
While higher temperature LED lighting may be appropriate for parking lots, highways, security systems and remote athletic fields, street lighting for residential areas should utilize LED bulbs in the range of 2700K or below to protect public heath.
Flagstaff, AZ has been recognized as the world's first International Dark Sky City. Here is their outdoor lighting ordinance.
The Municipal Research and Services Center (MRSC) is a nonprofit organization that helps local governments across Washington State serve their citizens by providing legal and policy guidance on a variety of topics, including lighting codes.
The California Lighting Technology Center (CLTC) at the University of California at Davis is a not-for-profit research, development and demonstration facility dedicated to accelerating the development and commercialization of next-generation, energy-efficient lighting and daylighting technologies.
Resources
The International Dark Sky Association is the leader in the movement to wipe out unnecessary light pollution. Their web site has some very useful guidelines for municipal lighting codes.
Grassroots Environmental Education, a science-based non-profit organization, has produced a Fact Sheet on LED Street Lighting.
The New York State Energy Research and Development Authority (NYSERDA) has multiple resources on their site for towns and villages who are considering upgrading their street lighting fixtures.
The U. S. Department of Energy's Municipal Solid-State Street Lighting Consortium shares technical information and experiences related to LED street and area lighting demonstrations and serves as an objective resource for evaluating new products on the market intended for those applications. Cities, power providers, and others who invest in street and area lighting are invited to join the Consortium and share their experiences.
References
[1] Pauley, S. M. (2004). Lighting for the human circadian clock: Recent research indicates that lighting has become a public health issue. Medical Hypotheses, 63(4), 588-596.
[2] Herman, P., et al. (2001). Frequency-domain fluorescence microscopy with the LED as a light source. Journal of Microscopy, 203(2), 176-181.
[3] Sandborn, P., et al. (2015). A return on investment analysis of applying health monitoring to LED lighting systems. Microelectronics Reliability, 55(3-4), 527-537.
[4] Jackson, L. E. (2003). The relationship of urban design to human health and condition. Landscape and Urban Planning, 64(4), 191-200.
[5] American Medical Association (2016) AMA Adopts Guidance to Reduce Hard from High Intensity Street Lights. https://www.ama-assn.org/ama-adopts-guidance-reduce-harm-high-intensity-street-lights
[6] Hunter, J. J., et al. (2012). The susceptibility of the retina to photochemical damage from visible light. Progress in Retinal and Eye Research, 31(1), 28-42.