Tuning white light has mostly been done in hospitals to aid patients in getting well. But prevention is better than cure and so, increasingly, we’re seeing studies on the effects of tuning white light in the working environment. The results of these studies are not yet fully in, but it appears people are not getting enough high-quality lighting in the workplace – whether in the day or at night. And that could be sending them to hospitals in the first place.

At the 2015 Lightfair International conference in New York City, biochemist PhD Dr. Joan E. Roberts presented her findings: ‘Lighting is not neutral! It will either have a positive or negative effect on human health’.

The science is not yet fully understood, however, and decisions once thought to be beneficial – exposing night shift workers to bluer or brighter white light in an attempt to perk night workers up, for example – proved to do the opposite. A Lighting Research Center (LRC) study instead showed that ‘red light could be used to maintain alertness in shift workers without affecting their circadian phase’.

Are LEDs up to it?

Not surprisingly, whether LEDs can deliver the quality of light workers need in the day and at night is a hot topic among those involved in the LED industry – manufacturers and lighting designers alike. Another hot topic (and trending offering by LED light manufacturers) is ‘tunable’ white light – products and lighting systems capable of changing the apparent temperature of light from cool blues (6500 Kelvin [K]) to warm amber lighting (2200 K).

According to the Juno Lighting Group, what is needed are LED lighting systems that can effectively deliver the ‘optimum amount of energy in the circadian-stimulating spectra’ depending on a time of day – and these lights should provide circadian benefits even at half the brightness of regular lights. This is a big challenge for LED manufacturers since even non-LED lamps currently marketed as ‘full spectrum’ currently fail to deliver circadian-optimized spectra. Indeed, when it comes to circadian-optimized light, full spectrum shouldn’t be, the objective. LRC states that ‘to maximize efficiency in affecting the circadian system, a light source should not mimic a full spectrum, but instead, should maximize only short wavelengths’. A 2011 Journal of Environmental Management study indicates that LED lights with the same light output as high-pressure sodium street lamps are five times more likely to disrupt circadian rhythms – leading to a lack of enough sleep, and other health problems. This should be an area of immediate concern for LED manufacturers.

Then there’s the area of control systems. Currently, only few luminaire manufacturers that also produce control systems – preferring to leave it instead to control systems manufacturers. Currently, most control systems are complex and not specifically designed for the circadian rhythm. It would take some time before a simple, human-centric, control system is produced.

Another stumbling block to developing more health-promoting LED lighting systems is not enough public interest. The Juno Lighting Group says to focus on ‘human-centric’ (circadian-optimized) lighting decreased in the European Light + Building Show from 2012-2014 which, they think, is due in part to ‘not enough project requests to drive development’. The general public is now only starting to become aware of how the quality of workplace lighting affects their health.

At the moment...

While the right amount and quality of human-centric lighting are not yet fully understood, lighting designers must keep themselves updated with the latest knowledge. This should help keep the harmful effects of wrong lighting decisions in the workplace to a minimum.

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