Report of the Council on Science and Public Health — File 201857

© 2016 American Medical Association. All rights reserved. REPORT OF THE COUNCIL ON SCIENCE AND PUBLIC HEALTH CSAPH Report 2-A-16 Subject: Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting Presented by: Louis J. Kraus, MD, Chair Referred to: Reference Committee E (Theodore Zanker, MD, Chair) INTRODUCTION 1 2 With the advent of highly efficient and bright light emitting diode (LED) lighting, strong economic 3 arguments exist to overhaul the street lighting of U.S. roadways.1-3 Valid and compelling reasons 4 driving the conversion from conventional lighting include the inherent energy efficiency and longer 5 lamp life of LED lighting, leading to savings in energy use and reduced operating costs, including 6 taxes and maintenance, as well as lower air pollution burden from reduced reliance on fossil-based 7 carbon fuels. 8 9 Not all LED light is optimal, however, when used as street lighting. Improper design of the lighting 10 fixture can result in glare, creating a road hazard condition.4,5 LED lighting also is available in 11 various color correlated temperatures. Many early designs of white LED lighting generated a color 12 spectrum with excessive blue wavelength. This feature further contributes to disability glare, i.e., 13 visual impairment due to stray light, as blue wavelengths are associated with more scattering in the 14 human eye, and sufficiently intense blue spectrum damages retinas.6,7 The excessive blue spectrum 15 also is environmentally disruptive for many nocturnal species. Accordingly, significant human and 16 environmental concerns are associated with short wavelength (blue) LED emission. Currently, 17 approximately 10% of existing U.S. street lighting has been converted to solid state LED 18 technology, with efforts underway to accelerate this conversion. The Council is undertaking this 19 report to assist in advising communities on selecting among LED lighting options in order to 20 minimize potentially harmful human health and environmental effects. 21 22 METHODS 23 24 English language reports published between 2005 and 2016 were selected from a search of the 25 PubMed and Google Scholar databases using the MeSH terms “light,” “lighting methods,” 26 “color,” “photic stimulation,” and “adverse effects,” in combination with “circadian 27 rhythm/physiology/radiation effects,” “radiation dosage/effects,” “sleep/physiology,” “ecosystem,” 28 “environment,” and “environmental monitoring.” Additional searches using the text terms “LED” 29 and “community,” “street,” and “roadway lighting” were conducted. Additional information and 30 perspective were supplied by recognized experts in the field. 31 32 ADVANTAGES AND DISADVANTAGES OF LED STREET LIGHTS 33 34 The main reason for converting to LED street lighting is energy efficiency; LED lighting can 35 reduce energy consumption by up to 50% compared with conventional high pressure sodium (HPS) 36

CSAPH Rep. 2-A-16 -- page 2 of 8 lighting. LED lighting has no warm up requirement with a rapid “turn on and off” at full intensity. 1 In the event of a power outage, LED lights can turn on instantly when power is restored, as 2 opposed to sodium-based lighting requiring prolonged warm up periods. LED lighting also has the 3 inherent capability to be dimmed or tuned, so that during off peak usage times (e.g., 1 to 5 AM), 4 further energy savings can be achieved by reducing illumination levels. LED lighting also has a 5 much longer lifetime (15 to 20 years, or 50,000 hours), reducing maintenance costs by decreasing 6 the frequency of fixture or bulb replacement. That lifespan exceeds that of conventional HPS 7 lighting by 2-4 times. Also, LED lighting has no mercury or lead, and does not release any toxic 8 substances if damaged, unlike mercury or HPS lighting. The light output is very consistent across 9 cold or warm temperature gradients. LED lights also do not require any internal reflectors or glass 10 covers, allowing higher efficiency as well, if designed properly.8,9 11 12 Despite the benefits of LED lighting, some potential disadvantages are apparent. The initial cost is 13 higher than conventional lighting; several years of energy savings may be required to recoup that 14 initial expense.10 The spectral characteristics of LED lighting also can be problematic. LED 15 lighting is inherently narrow bandwidth, with "white" being obtained by adding phosphor coating 16 layers to a high energy (such as blue) LED. These phosphor layers can wear with time leading to a 17 higher spectral response than was designed or intended. Manufacturers address this problem with 18 more resistant coatings, blocking filters, or use of lower color temperature LEDs. With proper 19 design, higher spectral responses can be minimized. LED lighting does not tend to abruptly “burn 20 out,” rather it dims slowly over many years. An LED fixture generally needs to be replaced after it 21 has dimmed by 30% from initial specifications, usually after about 15 to 20 years.1,11 22 23 Depending on the design, a large amount blue light is emitted from some LEDs that appear white 24 to the naked eye. The excess blue and green emissions from some LEDs lead to increased light 25 pollution, as these wavelengths scatter more within the eye and have detrimental environmental 26 and glare effects. LED’s light emissions are characterized by their correlated color temperature 27 (CCT) index.12,13 The first generation of LED outdoor lighting and units that are still widely being 28 installed are “4000K” LED units. This nomenclature (Kelvin scale) reflects the equivalent color of 29 a heated metal object to that temperature. The LEDs are cool to the touch and the nomenclature has 30 nothing to do with the operating temperature of the LED itself. By comparison, the CCT associated 31 with daylight light levels is equivalent to 6500K, and high pressure sodium lighting (the current 32 standard) has a CCT of 2100K. Twenty-nine percent of the spectrum of 4000K LED lighting is 33 emitted as blue light, which the human eye perceives as a harsh white color. Due to the point- 34 source nature of LED lighting, studies have shown that this intense blue point source leads to 35 discomfort and disability glare.14 36 37 More recently engineered LED lighting is now available at 3000K or lower. At 3000K, the human 38 eye still perceives the light as “white,” but it is slightly warmer in tone, and has about 21% of its 39 emission in the blue-appearing part of the spectrum. This emission is still very blue for the 40 nighttime environment, but is a significant improvement over the 4000K lighting because it 41 reduces discomfort and disability glare. Because of different coatings, the energy efficiency of 42 3000K lighting is only 3% less than 4000K, but the light is more pleasing to humans and has less 43 of an impact on wildlife. 44 45 Glare 46 47 Disability glare is defined by the Department of Transportation (DOT) as the following: 48 49 “Disability glare occurs when the introduction of stray light into the eye reduces the ability to 50 resolve spatial detail. It is an objective impairment in visual performance.” 51

CSAPH Rep. 2-A-16 -- page 3 of 8 Classic models of this type of glare attribute the deleterious effects to intraocular light scatter in the 1 eye. Scattering produces a veiling luminance over the retina, which effectively reduces the contrast 2 of stimulus images formed on the retina. The disabling effect of the veiling luminance has serious 3 implications for nighttime driving visibility.15 4 5 Although LED lighting is cost efficient and inherently directional, it paradoxically can lead to 6 worse glare than conventional lighting. This glare can be greatly minimized by proper lighting 7 design and engineering. Glare can be magnified by improper color temperature of the LED, such as 8 blue-rich LED lighting. LEDs are very intense point sources that cause vision discomfort when 9 viewed by the human eye, especially by older drivers. This effect is magnified by higher color 10 temperature LEDs, because blue light scatters more within the human eye, leading to increased 11 disability glare.16 12 13 In addition to disability glare and its impact on drivers, many residents are unhappy with bright 14 LED lights. In many localities where 4000K and higher lighting has been installed, community 15 complaints of glare and a “prison atmosphere” by the high intensity blue-rich lighting are common. 16 Residents in Seattle, WA have demanded shielding, complaining they need heavy drapes to be 17 comfortable in their own homes at night.17 Residents in Davis, CA demanded and succeeded in 18 getting a complete replacement of the originally installed 4000K LED lights with the 3000K 19 version throughout the town at great expense.18 In Cambridge, MA, 4000K lighting with dimming 20 controls was installed to mitigate the harsh blue-rich lighting late at night. Even in places with a 21 high level of ambient nighttime lighting, such as Queens in New York City, many complaints were 22 made about the harshness and glare from 4000K lighting.19 In contrast, 3000K lighting has been 23 much better received by citizens in general. 24 25 Unshielded LED Lighting 26 27 Unshielded LED lighting causes significant discomfort from glare. A French government report 28 published in 2013 stated that due to the point source nature of LED lighting, the luminance level of 29 unshielded LED lighting is sufficiently high to cause visual discomfort regardless of the position, 30 as long as it is in the field of vision. As the emission surfaces of LEDs are highly concentrated 31 point sources, the luminance of each individual source easily exceeds the level of visual 32 discomfort, in some cases by a factor of 1000.17 33 34 Discomfort and disability glare can decrease visual acuity, decreasing safety and creating a road 35 hazard. Various testing measures have been devised to determine and quantify the level of glare 36 and vision impairment by poorly designed LED lighting.20 Lighting installations are typically 37 tested by measuring foot-candles per square meter on the ground. This is useful for determining the 38 efficiency and evenness of lighting installations. This method, however, does not take into account 39 the human biological response to the point source. It is well known that unshielded light sources 40 cause pupillary constriction, leading to worse nighttime vision between lighting fixtures and 41 causing a “veil of illuminance” beyond the lighting fixture. This leads to worse vision than if the 42 light never existed at all, defeating the purpose of the lighting fixture. Ideally LED lighting 43 installations should be tested in real life scenarios with effects on visual acuity evaluated in order to 44 ascertain the best designs for public safety. 45 46 Proper Shielding 47 48 With any LED lighting, proper attention should be paid to the design and engineering features. 49 LED lighting is inherently a bright point source and can cause eye fatigue and disability glare if it 50 is allowed to directly shine into human eyes from roadway lighting. This is mitigated by proper 51

CSAPH Rep. 2-A-16 -- page 4 of 8 design, shielding and installation ensuring that no light shines above 80 degrees from the 1 horizontal. Proper shielding also should be used to prevent light trespass into homes alongside the 2 road, a common cause of citizen complaints. Unlike current HPS street lighting, LEDs have the 3 ability to be controlled electronically and dimmed from a central location. Providing this additional 4 control increases the installation cost, but may be worthwhile because it increases long term energy 5 savings and minimizes detrimental human and environmental lighting effects. In environmentally 6 sensitive or rural areas where wildlife can be especially affected (e.g., near national parks or bio- 7 rich zones where nocturnal animals need such protection), strong consideration should be made for 8 lower emission LEDs (e.g., 3000K or lower lighting with effective shielding). Strong consideration 9 also should be given to the use of filters to block blue wavelengths (as used in Hawaii), or to the 10 use of inherent amber LEDs, such as those deployed in Quebec. Blue light scatters more widely 11 (the reason the daytime sky is “blue”), and unshielded blue-rich lighting that travels along the 12 horizontal plane increases glare and dramatically increases the nighttime sky glow caused by 13 excessive light pollution. 14 15 POTENTIAL HEALTH EFFECTS OF “WHITE” LED STREET LIGHTING 16 17 Much has been learned over the past decade about the potential adverse health effects of electric 18 light exposure, particularly at night.21-25 The core concern is disruption of circadian rhythmicity. 19 With waning ambient light, and in the absence of electric lighting, humans begin the transition to 20 nighttime physiology at about dusk; melatonin blood concentrations rise, body temperature drops, 21 sleepiness grows, and hunger abates, along with several other responses. 22 23 A number of controlled laboratory studies have shown delays in the normal transition to nighttime 24 physiology from evening exposure to tablet computer screens, backlit e-readers, and room light 25 typical of residential settings.26-28 These effects are wavelength and intensity dependent, 26 implicating bright, short wavelength (blue) electric light sources as disrupting transition. These 27 effects are not seen with dimmer, longer wavelength light (as from wood fires or low wattage 28 incandescent bulbs). In human studies, a short-term detriment in sleep quality has been observed 29 after exposure to short wavelength light before bedtime. Although data are still emerging, some 30 evidence supports a long-term increase in the risk for cancer, diabetes, cardiovascular disease and 31 obesity from chronic sleep disruption or shiftwork and associated with exposure to brighter light 32 sources in the evening or night.25,29 33 34 Electric lights differ in terms of their circadian impact.30 Understanding the neuroscience of 35 circadian light perception can help optimize the design of electric lighting to minimize circadian 36 disruption and improve visual effectiveness. White LED streetlights are currently being marketed 37 to cities and towns throughout the country in the name of energy efficiency and long term cost 38 savings, but such lights have a spectrum containing a strong spike at the wavelength that most 39 effectively suppresses melatonin during the night. It is estimated that a “white” LED lamp is at 40 least 5 times more powerful in influencing circadian physiology than a high pressure sodium light 41 based on melatonin suppression.31 Recent large surveys found that brighter residential nighttime 42 lighting is associated with reduced sleep time, dissatisfaction with sleep quality, nighttime 43 awakenings, excessive sleepiness, impaired daytime functioning, and obesity.29,32 Thus, white LED 44 street lighting patterns also could contribute to the risk of chronic disease in the populations of 45 cities in which they have been installed. Measurements at street level from white LED street lamps 46 are needed to more accurately assess the potential circadian impact of evening/nighttime exposure 47 to these lights. 48

CSAPH Rep. 2-A-16 -- page 5 of 8 ENVIRONMENTAL EFFECTS OF LED LIGHTING 1 2 The detrimental effects of inefficient lighting are not limited to humans; 60% of animals are 3 nocturnal and are potentially adversely affected by exposure to nighttime electrical lighting. Many 4 birds navigate by the moon and star reflections at night; excessive nighttime lighting can lead to 5 reflections on glass high rise towers and other objects, leading to confusion, collisions and 6 death.33 Many insects need a dark environment to procreate, the most obvious example being 7 lightning bugs that cannot “see” each other when light pollution is pronounced. Other 8 environmentally beneficial insects are attracted to blue-rich lighting, circling under them until they 9 are exhausted and die.34,35 Unshielded lighting on beach areas has led to a massive drop in turtle 10 populations as hatchlings are disoriented by electrical light and sky glow, preventing them from 11 reaching the water safely.35-37 Excessive outdoor lighting diverts the hatchlings inland to their 12 demise. Even bridge lighting that is “too blue” has been shown to inhibit upstream migration of 13 certain fish species such as salmon returning to spawn. One such overly lit bridge in Washington 14 State now is shut off during salmon spawning season. 15 16 Recognizing the detrimental effects of light pollution on nocturnal species, U.S. national parks 17 have adopted best lighting practices and now require minimal and shielded lighting. Light pollution 18 along the borders of national parks leads to detrimental effects on the local bio-environment. For 19 example, the glow of Miami, FL extends throughout the Everglades National Park. Proper 20 shielding and proper color temperature of the lighting installations can greatly minimize these types 21 of harmful effects on our environment. 22 23 CONCLUSION 24 25 Current AMA Policy supports efforts to reduce light pollution. Specific to street lighting, Policy H- 26 135.932 supports the implementation of technologies to reduce glare from roadway lighting. Thus, 27 the Council recommends that communities considering conversion to energy efficient LED street 28 lighting use lower CCT lights that will minimize potential health and environmental effects. The 29 Council previously reviewed the adverse health effects of nighttime lighting, and concluded that 30 pervasive use of nighttime lighting disrupts various biological processes, creating potentially 31 harmful health effects related to disability glare and sleep disturbance.25 32 33 RECOMMENDATIONS 34 35 The Council on Science and Public Health recommends that the following statements be adopted, 36 and the remainder of the report filed. 37 38 1. That our American Medical Association (AMA) support the proper conversion to community- 39 based Light Emitting Diode (LED) lighting, which reduces energy consumption and decreases 40 the use of fossil fuels. (New HOD Policy) 41 42 2. That our AMA encourage minimizing and controlling blue-rich environmental lighting by 43 using the lowest emission of blue light possible to reduce glare. (New HOD Policy) 44 45 3. That our AMA encourage the use of 3000K or lower lighting for outdoor installations such as 46 roadways. All LED lighting should be properly shielded to minimize glare and detrimental 47 human and environmental effects, and consideration should be given to utilize the ability of 48 LED lighting to be dimmed for off-peak time periods. (New HOD Policy) 49 Fiscal Note: Less than $500

CSAPH Rep. 2-A-16 -- page 6 of 8 REFERENCES 1. Municipal Solid State Street Lighting Consortium. http://www1.eere.energy.gov/buildings/ssl/consortium.html. Accessed April 4, 2016. 2. Illuminating Engineering Society RP-8 – Guide to Roadway Lighting. http://www.ies.org/? 2014. Accessed April 4, 2016. 3. LED Lighting Facts–A Program of the United States Department of Energy. http://www.lightingfacts.com. Accessed April 5, 2016. 4. Lin Y, Liu Y, Sun Y, Zhu X, Lai J, Heynderickz I. Model predicting discomfort glare caused by LED road lights. Opt Express. 2014;22(15):18056-71. 5. Gibbons RB, Edwards CJ. A review of disability and discomfort glare research and future direction. 18th Biennial TRB Visibility Symposium, College Station TX, United States, April 17-19, 2007. 6. Shang YM, Wang GS, Sliney D, Yang CH, Lee LL. White light–emitting diodes (LEDs) at domestic lighting levels and retinal injury in a rat model. Environ Health Perspect. 2014:122(3):269-76. 7. Lougheed T. Hidden blue hazard? LED lighting and retinal damage in rats, Environ Health Perspect. 2014;122(3):A81. 8. A Municipal Guide for Converting to LED Street Lighting, (http://www1.eere.energy.gov/buildings/ssl/consortium.html) 10/13/2013. 9. In depth: Advantages of LED Lighting. http://energy.ltgovernors.com/in-depth-advantages-of- led-lighting.html. Accessed April 5, 2016. 10. Silverman H. How LED Streetlights Work. HowStuffWorks.com. June 22, 2009. http://science.howstuffworks.com/environmental/green-tech/sustainable/led- streetlight.htm. Accessed April 7, 2016. 11. Jin H, Jin S, Chen L, Cen S, Yuan K. Research on the lighting performance of LED street lights with different color temperatures. IEEE Photonics Journal. 2015;24(6):975- 78. http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7328247. Accessed April 7, 2016. 12. Morris N. LED there be light. Nick Morris predicts a bright future for LEDs. Electrooptics.com. http://www.electrooptics.com/features/junjul06/junjul06leds.html. Accessed April 7, 2016. 13. Mills MP. The LED illumination revolution. Forbes Magazine. February 27, 2008. http://www.forbes.com/2008/02/27/incandescent-led-cfl-pf- guru_in_mm_0227energy_inl.html. Accessed April 5, 2016.

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CSAPH Rep. 2-A-16 -- page 8 of 8 28. Gooley JJ, Chamberlain K, Smith KA, et al. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. J Clin Endocrinol Metab. 2011;96:E463-72. 29. Koo YS, Song JY, Joo EY, et al. Outdoor artificial light at night, obesity, and sleep health: Cross-sectional analysis in the KoGES study. Chronobiol Int. 2016;33(3):301-14. 30. Lucas RJ, Peirson SN, Berson DM, et al. Measuring and using light in the melanopsin age. Trends Neurosci. 2014;37:1-9. 31. Falchi F, Cinzano P, Elvidge CD, Keith DM, Haim A. Limiting the impact of light pollution on human health, environment and stellar visibility. J Environ Manage. 2011;92:2714-22. 32. Ohayon M, Milesi C. Sleep deprivation/insomnia and exposure to street lights in the American general population. American Academy of Neurology Annual Meeting. April 15-21, 2016. Vancouver, BC. 33. Pawson SM, Bader MK. Led lighting increases the ecological impact of light pollution irrespective of color temperature. Ecological Applications. 2014;24:1561-68. 34. Gaston K, Davies T, Bennie J, Hopkins J. Reducing the ecological consequences of night-time light pollution: Options and developments. J Appl Ecol. 2012;49(6):1256–66. 35. Salmon M. Protecting sea turtles from artificial night lighting at Florida’s oceanic beaches. In- Rich C, Longcore T (eds.). Ecological Consequences of Artificial Night Lighting. 2006:141-68. Island Press, Washington, DC. 36. Rusenko KW, Mann JL, Albury R, Moriarty JE, Carter HL. Is the wavelength of city glow getting shorter? Parks with no beachfront lights record adult aversion and hatchling disorientations in 2004. Kalb H, Rohde A, Gayheart K, Shanker, K, compilers. 2008. Proceedings of the Twenty-fifth Annual Symposium on Sea Turtle Biology and Conservation, NOAA Technical Memorandum NMFS-SEFSC-582, 204pp. http://www.nmfs.noaa.gov/pr/pdfs/species/turtlesymposium2005.pdf 37. Rusenko KW, Newman R, Mott C, et al. Using GIS to determine the effect of sky glow on nesting sea turtles over a ten year period. Jones TT, Wallace BP, compilers. 2012. Proceedings of the Thirty-first Annual Symposium on Sea Turtle Biology and Conservation. NOAA Technical Memorandum NOAA NMFS-SEFSC-631:32p. Acknowledgement: The Council thanks George Brainard, PhD (Thomas Jefferson University); Richard Stevens, PhD (University Connecticut Health Center); and Mario Motta, MD (CSAPH, Tufts Medical School) for their contributions in preparing the initial draft of this report, and the commentary by Travis Longcore, PhD, on the ecological impact of nighttime electrical lighting.