All Against Blue-White LED Street Lights
All against LED Street Lights that are Blue/White as they are Bad for Human Health and All Wildlife along with the Environment...
Introduction
Poorly designed outdoor lighting is one of the most conspicuous forms of energy waste. "e global call to conserve energy resources has cities scrambling to replace public lighting with brand new systems. In the U.S., changes are further spurred by federal economic stimulus funding. Technology under development for decades has produced a number of options, many with a potential for energy savings. Of these, high brightness white light emitting diodes (LEDs) have emerged as an industry favourite. Many of these new options have never been applied on a broad scale, and may have unexpected consequences if widely used for outdoor lighting. In particular, the stronger blue emission produced by white light sources, such as LEDs, has been shown to have increased negative effects on astronomy and sky glow, and has a greater impact on animal behaviour and circadian rhythms than other types of light. Widespread installation of white light sources rich in blue emission is among the largest concerns of the dark sky movement. Lamp choices made today will affect night lighting for decades, maybe longer. It is imperative that decision makers understand the consequences—both positive and negative—of lighting choices. On 4 May 2010, IDA released a comprehensive review paper titled Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting, to raise awareness of likely or potential negative consequences of blue-rich white light (BRWL) and to help governments and the industry balance these consequences against the more widely touted benefits. This article provides an introduction to the controversy surrounding BRWL. To fully understand the problems, we must first understand its properties.
Sky Glow
Atmospheric scatter and sky glow increased scattering from BRWL sources leads to 15% to 20% more sky glow detectable by an astronomical instrument than high pressure sodium (HPS) or low-pressure sodium (LPS). Due to the eye’s increased sensitivity to blue light at lower levels, the visual brightness of sky glow produced by BRWL can appear three to five times brighter than it appears with HPS and up to 15 times as bright when compared to LPS. BRWL contributes to sky glow in a portion of the spectrum that currently suffers little artificial sky glow. BRWL introduces a different type of light pollution, to a part of the spectrum that is relatively dark and relatively less polluted. "Thus, widespread use of BRWL will substantially increase the degradation of visual and astronomical sky quality.
Ecological considerations
Artificial light in the environment must be considered a chronic impairment of habitat. However, while there is evidence that artificial light affects species behaviour, diet, movement, and mating, the relationship between artificial light and wildlife has rarely received the level of study that definitively answers questions about spectrum and illumination threshold. While no absolute conclusions have been drawn, previous research suggests BRWL heightens response in certain species. Loggerhead sea turtles are ten times more likely to be attracted to light at 450 nm than 600 nm, with four Atlantic sea turtle species showing a similar spectral misorientation response. Light sources that have a strong blue and ultraviolet component are particularly attractive to insects, though broad spectrum sources are known to attract insects as well. Changes in insect behaviour often affect numerous other species that prey on insects, including amphibians and bats. Additionally, the circadian response of wildlife often resembles that of humans; thus even if a species exhibits no behavioural or orientation response to BRWL, such light may be altering the diurnal and nocturnal patterns of wildlife. Evidence does not indicate that the behaviour of all species is altered by short-wavelength light. Some birds have exhibited a stronger attraction to red light, while others avoid it. It is because of these discrepancies and interspecies behavioural unpredictably that IDA advocates for comprehensive studies that investigate spectral effects to be performed before radically different light sources are widely introduced into nocturnal ecosystems.
Circadian disruption
Light inhibits secretion of the hormone melatonin. Blue light between 430 and 510 nm shows the greatest disruption of circadian rhythm and melatonin secretion, with peak sensitivity around 460 nm. Melatonin levels dictate circadian cycles and play a role in immune system function of animals and humans. Studies have effectively linked low melatonin production with the growth of some human cancers, notably breast cancer. Some studies suggest that the illumination threshold for melatonin disruption is quite low, but no exact amounts have been found. All potential compounding factors have not been ruled out, and crucial research concerning realistic incidental exposure to outdoor lighting, as well as the spectral characteristics of such lighting, has not been published. However, the effects of blue light on melatonin production, and the effects of melatonin on human cancer growth in certain laboratory experiments, are uncontroversial.
While a firm connection between outdoor lighting and cancer has not yet been established, if true it is clear that the blue component of such light would be a greater risk factor. Less than two weeks after IDA published this white paper, the Rensselaer Polytechnic Institute’s Lighting Research Centre released the study "The Potential of Outdoor Lighting for Stimulating the Human Circadian System." The study expresses scepticism of claims that BRWL can affect circadian rhythm to the point of serious harm, yet shows that exposure to 6,500K CCT light at street-light lighting levels for just one hour is expected to show measurable effects on human melatonin production. Its statement that “…continued investigations of light-induced disruption of the human circadian system are clearly warranted” corroborates IDA’s assertion that further testing is necessary before the widespread introduction of new BRWL technologies. While IDA clearly does not want to raise undo alarm or over-generalize the connection between human health and artificial light, the widespread adoption of BRWL sources and the number of people potentially affected result in a risk factor that must be acknowledged by engineering, environmental and human health professionals.
A Unified Approach
Thomas Edison quipped that he had to first learn 1,000 ways to not build a light bulb before he learned how to build one. With each attempt, he drew upon his wide-ranging intellect, his concern for his fellow man, and his fortitude for hard work. His efforts resulted in the #fist viable electric lamp 130 years ago. Today we are still “always finding a better way” to use electric lighting, particularly outdoors. The question before us now is far deeper and wider than what is the optimal technology for producing light. Though cultural tastes, government initiatives, short-term economics, and environmental ethics may dictate market fads, professional lighting engineers recognize that the best light is one that balances a range of needs and concerns. Objective, professional research is needed to provide manufacturers with data needed to minimize light pollution while considering other variables. A light source, fixture, or design that optimizes only one aspect will likely fail miserably when introduced in a wider context. Sustainable lighting must cross multiple realms—technical, environmental, and socio-economic. The IDA encourages such a holistic approach, and will continue to ensure that the environmental, cultural, social, and civic aspects of protecting dark skies and the night-time environment are collectively addressed by the lighting industry, government, and community leaders.
The Future of Light
Solid state lighting has the potential to revolutionize outdoor lighting in a profoundly positive way. LED lighting in particular can be fine tuned to decrease most negative impact on the night environment. Their directionality and controllability opens the door to energy saving innovations and facilitates the large scale implementation of automatic timers, dimmers, and sensors. LED Efficiency and longevity may provide a real contribution to the world’s lighting needs. Right now, the variance and speed in LED product development is nothing short of astounding. Basic SSL technology has advanced to the point where a broad range of finely tuned and radically different LED applications are appearing more or less continuously on the market. If developers concentrate on creating high efficacy lamps rich in warm hues, LED technology could become an outstanding source for energy efficient, night sky friendly outdoor lighting. Already, some LED developers are creating a highly efficient product with a spectral power distribution (SPD) that avoids peaks in any wavelength. Driven by an indicated aesthetic preference for warm toned hues, these manufacturers are developing high efficacy commercial LED products with significantly reduced blue spectrum emissions. Philips Lumileds, Osram, and Seoul Semiconductor have created notably broad spectrum light sources at efficiencies that are among the industry’s best, and tout a significantly increased Colour Rendition Index. Cree is developing a product that emits less blue light than some conventional High Intensity Discharge lamps used today. If development continues to advance in this way, dark sky advocates and industry leaders will soon have a number of eminently usable LED products for residential, commercial, and public application.
However, warm white LED technology cannot by itself provide the answer to the world..
Introduction
Poorly designed outdoor lighting is one of the most conspicuous forms of energy waste. "e global call to conserve energy resources has cities scrambling to replace public lighting with brand new systems. In the U.S., changes are further spurred by federal economic stimulus funding. Technology under development for decades has produced a number of options, many with a potential for energy savings. Of these, high brightness white light emitting diodes (LEDs) have emerged as an industry favourite. Many of these new options have never been applied on a broad scale, and may have unexpected consequences if widely used for outdoor lighting. In particular, the stronger blue emission produced by white light sources, such as LEDs, has been shown to have increased negative effects on astronomy and sky glow, and has a greater impact on animal behaviour and circadian rhythms than other types of light. Widespread installation of white light sources rich in blue emission is among the largest concerns of the dark sky movement. Lamp choices made today will affect night lighting for decades, maybe longer. It is imperative that decision makers understand the consequences—both positive and negative—of lighting choices. On 4 May 2010, IDA released a comprehensive review paper titled Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting, to raise awareness of likely or potential negative consequences of blue-rich white light (BRWL) and to help governments and the industry balance these consequences against the more widely touted benefits. This article provides an introduction to the controversy surrounding BRWL. To fully understand the problems, we must first understand its properties.
Sky Glow
Atmospheric scatter and sky glow increased scattering from BRWL sources leads to 15% to 20% more sky glow detectable by an astronomical instrument than high pressure sodium (HPS) or low-pressure sodium (LPS). Due to the eye’s increased sensitivity to blue light at lower levels, the visual brightness of sky glow produced by BRWL can appear three to five times brighter than it appears with HPS and up to 15 times as bright when compared to LPS. BRWL contributes to sky glow in a portion of the spectrum that currently suffers little artificial sky glow. BRWL introduces a different type of light pollution, to a part of the spectrum that is relatively dark and relatively less polluted. "Thus, widespread use of BRWL will substantially increase the degradation of visual and astronomical sky quality.
Ecological considerations
Artificial light in the environment must be considered a chronic impairment of habitat. However, while there is evidence that artificial light affects species behaviour, diet, movement, and mating, the relationship between artificial light and wildlife has rarely received the level of study that definitively answers questions about spectrum and illumination threshold. While no absolute conclusions have been drawn, previous research suggests BRWL heightens response in certain species. Loggerhead sea turtles are ten times more likely to be attracted to light at 450 nm than 600 nm, with four Atlantic sea turtle species showing a similar spectral misorientation response. Light sources that have a strong blue and ultraviolet component are particularly attractive to insects, though broad spectrum sources are known to attract insects as well. Changes in insect behaviour often affect numerous other species that prey on insects, including amphibians and bats. Additionally, the circadian response of wildlife often resembles that of humans; thus even if a species exhibits no behavioural or orientation response to BRWL, such light may be altering the diurnal and nocturnal patterns of wildlife. Evidence does not indicate that the behaviour of all species is altered by short-wavelength light. Some birds have exhibited a stronger attraction to red light, while others avoid it. It is because of these discrepancies and interspecies behavioural unpredictably that IDA advocates for comprehensive studies that investigate spectral effects to be performed before radically different light sources are widely introduced into nocturnal ecosystems.
Circadian disruption
Light inhibits secretion of the hormone melatonin. Blue light between 430 and 510 nm shows the greatest disruption of circadian rhythm and melatonin secretion, with peak sensitivity around 460 nm. Melatonin levels dictate circadian cycles and play a role in immune system function of animals and humans. Studies have effectively linked low melatonin production with the growth of some human cancers, notably breast cancer. Some studies suggest that the illumination threshold for melatonin disruption is quite low, but no exact amounts have been found. All potential compounding factors have not been ruled out, and crucial research concerning realistic incidental exposure to outdoor lighting, as well as the spectral characteristics of such lighting, has not been published. However, the effects of blue light on melatonin production, and the effects of melatonin on human cancer growth in certain laboratory experiments, are uncontroversial.
While a firm connection between outdoor lighting and cancer has not yet been established, if true it is clear that the blue component of such light would be a greater risk factor. Less than two weeks after IDA published this white paper, the Rensselaer Polytechnic Institute’s Lighting Research Centre released the study "The Potential of Outdoor Lighting for Stimulating the Human Circadian System." The study expresses scepticism of claims that BRWL can affect circadian rhythm to the point of serious harm, yet shows that exposure to 6,500K CCT light at street-light lighting levels for just one hour is expected to show measurable effects on human melatonin production. Its statement that “…continued investigations of light-induced disruption of the human circadian system are clearly warranted” corroborates IDA’s assertion that further testing is necessary before the widespread introduction of new BRWL technologies. While IDA clearly does not want to raise undo alarm or over-generalize the connection between human health and artificial light, the widespread adoption of BRWL sources and the number of people potentially affected result in a risk factor that must be acknowledged by engineering, environmental and human health professionals.
A Unified Approach
Thomas Edison quipped that he had to first learn 1,000 ways to not build a light bulb before he learned how to build one. With each attempt, he drew upon his wide-ranging intellect, his concern for his fellow man, and his fortitude for hard work. His efforts resulted in the #fist viable electric lamp 130 years ago. Today we are still “always finding a better way” to use electric lighting, particularly outdoors. The question before us now is far deeper and wider than what is the optimal technology for producing light. Though cultural tastes, government initiatives, short-term economics, and environmental ethics may dictate market fads, professional lighting engineers recognize that the best light is one that balances a range of needs and concerns. Objective, professional research is needed to provide manufacturers with data needed to minimize light pollution while considering other variables. A light source, fixture, or design that optimizes only one aspect will likely fail miserably when introduced in a wider context. Sustainable lighting must cross multiple realms—technical, environmental, and socio-economic. The IDA encourages such a holistic approach, and will continue to ensure that the environmental, cultural, social, and civic aspects of protecting dark skies and the night-time environment are collectively addressed by the lighting industry, government, and community leaders.
The Future of Light
Solid state lighting has the potential to revolutionize outdoor lighting in a profoundly positive way. LED lighting in particular can be fine tuned to decrease most negative impact on the night environment. Their directionality and controllability opens the door to energy saving innovations and facilitates the large scale implementation of automatic timers, dimmers, and sensors. LED Efficiency and longevity may provide a real contribution to the world’s lighting needs. Right now, the variance and speed in LED product development is nothing short of astounding. Basic SSL technology has advanced to the point where a broad range of finely tuned and radically different LED applications are appearing more or less continuously on the market. If developers concentrate on creating high efficacy lamps rich in warm hues, LED technology could become an outstanding source for energy efficient, night sky friendly outdoor lighting. Already, some LED developers are creating a highly efficient product with a spectral power distribution (SPD) that avoids peaks in any wavelength. Driven by an indicated aesthetic preference for warm toned hues, these manufacturers are developing high efficacy commercial LED products with significantly reduced blue spectrum emissions. Philips Lumileds, Osram, and Seoul Semiconductor have created notably broad spectrum light sources at efficiencies that are among the industry’s best, and tout a significantly increased Colour Rendition Index. Cree is developing a product that emits less blue light than some conventional High Intensity Discharge lamps used today. If development continues to advance in this way, dark sky advocates and industry leaders will soon have a number of eminently usable LED products for residential, commercial, and public application.
However, warm white LED technology cannot by itself provide the answer to the world..