Page 59 - Lighting Magazine December 2017

the led controVersy | 2018 forECast
In the upcoming year, customers may ask you questions about health concerns regarding LED lighting. BY LINDA LONGO
Whenever a new technol- ogy emerges and takes o like wild re, inevitably thoughts turn to possible medical complications.
When earbuds became ubiquitous – starting with the Sony Walkman in late 1970s to more recently as ear pieces for MP4 players or mobile phones – reports were issued warning of potential hearing damage. As cell phones rose in popularity, studies were done to evaluate whether radiation emi ed from cell phones causes brain tissue damage.
The lighting industry has had its share of health precautions as well, from UV exposure emanating from halogen bulbs to mercury levels in compact uorescents, and now blue-light hazard coming from LEDs.
Since solid-state lighting technology has become mainstream for general indoor illumination, there is closer a ention being paid to any possible ill ef- fects. Your customers may ask you about the risks they might have heard, and part of your role as an LED lighting expert is to be aware of what is being said and what studies have shown so far.
For example, in June 2016 the American Medi- cal Association (AMA) issued a warning about bright white LED street lighting having, potentially, a harmful e ect on human health and the natural environment. The AMA’s o cial statement recom- mends that street lighting should not have a higher correlated color temperature than 3000K. (Note: higher Kelvin temperatures have more blue in the spectral content, which makes the light appear “whiter.”) The concern arises because many major U.S. cities have opted to retro t their street lighting with LEDs at 4000K and 5000K, which contain a high level of short-wavelength blue light.
The AMA is worried that LED light with high blue content can cause severe glare for drivers and pedestrians because it causes pupils to constrict. There is also concern for the bright white light inter- fering with birds’ migratory pa erns and, of course, the life of sea turtles in coastal environments.
In addition, the bright white of LEDs (from high levels of blue light) is thought to suppress the production of melatonin, resulting in disruptions in sleep and circadian rhythms.
It was these conversations in the medical com- munity regarding the possibility of retinal damage from LEDs – commonly referred to as “blue-light hazard” – that have caused many in the scienti c segment of the lighting industry to take a closer look.
A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute was re- leased in October that takes a practical, quantitative approach to evaluating light sources for blue-light hazard. The results of the study are published in the International Journal of Occupational Safety and Ergonomics in an article titled “Evaluating the Blue-Light Hazard from Solid State Lighting.”
In the study, LRC researchers John Bullough, An- drew Bierman, and Mark Rea evaluated the spectral radiant power characteristics of incandescent,
It was these conversations in the medical community regarding the possibility of retinal damage from LEDs – commonly referred to as “blue-light hazard” – that have caused many in the scienti c segment of the lighting industry to take a closer look.
december 2017 | enLIGHTenment magazine 57