Exposure to artificial blue light – Expert Reaction

A new report from Royal Society Te Apārangi summarises what we know about how our increased exposure to artificial blue light affects us and our environment. 

There is growing concern that the increased exposure to artificial sources of blue light from lighting and digital screens is having an effect on our health, wildlife and the night sky.

The report summarises the latest evidence on this topic and explores what we can do to protect ourselves and the environment from artificial blue light exposure outside daylight hours.

The SMC asked New Zealand experts to comment on the report, please feel free to use these comments in your reporting. 

Lindsay Bulman, Science Leader, Forest Protection, Scion, comments:

“Recent research has highlighted just how little artificial light it takes to have an impact on the environment.

“We were surprised that even small solar-powered LEDs, the kind people have in their gardens, can alter insect behaviour, attracting some and reducing the activeness of others. Research carried out by Scion scientists also found that nighttime lighting caused large changes in the feeding behaviour of the native black-backed gull Larus dominicanus, extending its feeding until at least 1am in an isolated location.

“If we want to minimise the effect of nighttime lighting on the environment we need to think about how, when and where we use lighting at home and in public spaces, and look at using lights that do not have a significant blue wavelength component.”

No conflict of interest.

Associate Professor Guy Warman, Chronobiology Group, Department of Anaesthesiology, School of Medicine, University of Auckland, comments:

“The Royal Society Te Apārangi’s document ‘Blue Light Aotearoa’ discussing the potential impacts of blue light on health and the environment, is both timely and important, particularly given the modern move to artificial light sources which produce ‘bluer’ light than we have previously been exposed to (such as LED lights in the home and public places, and blue light produced by electronic devices).

“The negative and positive effects of light in the blue end of the spectrum is an extremely important issue for scientists, policymakers and the general public alike.

“As scientists, we are now clear that the human body clock is strongly influenced by blue light. In particular, evening exposure to blue light can shift our body clocks to a later time zone resulting in shifts in our sleep times and causing sleep disturbances. A lack of morning light exposure can further exacerbate these problems. The effects of disruptions in our daily light exposure are far-ranging, and include long-term health issues such as cardiac disease and cancer.

“Our understanding of the effects of blue light on our biology is relatively new and there are a number of things we are still learning about. One such area is how much artificial light exposure we are getting in our everyday lives (and when). This certainly requires further research.

“The effect of blue light on biology is not, of course, restricted to humans. Other animals and plants are also affected by blue light, and the potential effects of this on natural populations of animals in New Zealand (and the potential usefulness of blue light for increasing production in our primary sector) should not be underestimated.

“In short, we are rapidly changing our lighting environment. In doing so we are having a profound effect on our biology and the biology of other living things. It is important that we try to understand (and where appropriate, mitigate) the effects of this.”

Conflict of interest statement: I was consulted regarding the document by the RSNZ.

Alan Gilmore, Retired Superintendent, University of Canterbury’s Mt John Observatory, and Manager, Aoraki-Mackenzie International Dark Sky Reserve, comments:

“This is an important and timely report given the move by many national and local authorities to LED lighting. The astronomical aspect is important for protecting night skies from scattered blue light. Many places in New Zealand are keen to enhance or protect their dark night skies for the enjoyment of local people and to encourage astro-tourism.

“The Mackenzie District Council has adopted a policy of installing low colour-temperature (2800K) street lighting to protect the gold-standard Aoraki-Mackenzie International Dark Sky Reserve. It is to be hoped that other local authorities will follow.

“Dark skies have always had scientific, cultural and environmental benefits. Now they can also be an economic advantage in attracting visitors who want to see a natural starry sky.”

No conflict of interest declared. 

Dr Bill Heffernan, Electric Power Engineering Centre, University of Canterbury comments:

Why have we seen increasing exposure to blue light?

“The most efficient, readily available, and reasonably cheap device for converting electricity to light is the LED. LEDs are available in many colours, and “white” light with varying colour temperatures and Colour Rendering Indices (CRIs) can be made by combining red, green, blue and other wavelengths. The CRI is a measure of how well the spectrum from a lamp mimics a reference spectrum, such as “overcast daylight”. If parts of the spectrum are completely missing from a lamp, objects of certain hues will appear to be of a different colour when viewed in lamplight or daylight (this often happens when clothes-shopping!).

“However, the most efficient and cost-effective way of making a ‘white’ LED lamp currently is to use a blue LED emitter with added phosphors – a process known as “phosphor-conversion”. The LED produces blue light, some of which is absorbed by the yellow phosphors with which the LED is coated – the energy absorbed by the phosphors is re-emitted at green, yellow and red wavelengths; the energy that is not absorbed comes straight through as blue (see page 7 of the report).

“Changing the type and quantity of phosphors alters the colour temperature, CRI and luminous efficacy. Thus most LED-based lamps emit a higher proportion of light energy at the blue end of the spectrum than any other widely-used electric lamp technology.”

Conflict of interest: I am not aware of any conflicts of interest.

Associate Professor Mirjam Münch, Sleep/Wake Research Centre, Massey University, comments:

“This report informs about various aspects of the impact of blue light on human health as well as consequences for nature and ecosystems.

“The report describes that different qualities and quantities of light can elicit a variety of physiological and behavioural responses – mainly depending on the time of day but also depending on the health, and age status of the person who is exposed to it.

“The report nicely underlines the importance of darkness at night e.g. for sleep. Both light during the day and darkness at night are the two main players which entrain the human circadian system to the external 24-day and thus, are crucial for general health and wellbeing in our populations.”

No conflict of interest.