A whiter shade of pale

MOST Europeans live under light-polluted skies and the first colour map of Europe at night, created with images from the International Space Station (ISS), shows a sharp increase in light pollution. The resulting picture is not a pretty one for the environment.

Over the last two decades, astronauts on the Space Station have witnessed how cities shine whiter at night as new street lighting technologies were introduced.

When ESA astronaut Samantha Cristoforetti gazed at Earth from orbit during her recent Minerva mission, cities glowed brighter than the stars. Since 2003, Samantha and other European astronauts have taken over a million pictures of Earth at night with digital cameras to demonstrate the true extent of light pollution.

A team of European researchers processed the pictures and compared them over time, showing a clear increase of lighting pollution in urban areas, and a shift towards whiter and bluer emissions. This is due to the widespread introduction of light-emitting diode lamps, or LED technology.

“As seen from space, the resulting image looks like a cancer scan or a fluorescent spider’s web that keeps growing,” says Alejandro Sánchez de Miguel, research fellow at the UK’s University of Exeter. Their recent paper highlights how invasive night lights are and their negative effects for the environment.

As Europe turns lights down in an urge to save energy, scientists warn that it should not only be about reducing bills – brighter nights are disrupting the night cycle for humans, animals and plants.

Colour pictures taken from the Space Station are the best source for scientists to map artificial light at night. Current satellite images are not fit for purpose because their colour sensitivity does not show low wavelength emissions with enough quality.

“Without the images taken by the astronauts, we would be driving blind into the environmental impact of the LED transition,” says Alejandro. “Astronaut photos have always been – and will always be – the baseline for night time Earth observations.”

The composite nighttime colour maps created before and after the spread of LED streetlight technology show a pronounced whitening of artificial light. See view of London from ISS at top of page - the images were taken 400 km above Earth by André Kuipers in 2012 (left) and by Samantha Cristoforetti in 2022.

The changes vary per country, and reflect different systems and policies when it comes to light the streets. Whereas there has been a marked increase in light pollution in Italy and the United Kingdom, countries like Germany and Austria show a less dramatic change in spectral emissions.

Milan was the first city in Europe to do a total conversion of its street lighting to white LEDs, and more than half of all the public street lighting in the UK was converted by early 2019.

Germany’s glow is whitening, and the country has a lot of fluorescent and mercury vapour lights still in use.

“By the end of this decade, all Europe could look white from space,” says Alejandro.

On the warmer side of the spectrum, Belgium shines in deep orange due to the widespread use of low-pressure sodium lights. High-pressure sodium lights make the Netherlands emit a golden glow.

According to the scientists, the transition towards white and blue-rich light radiation is eroding the natural nighttime cycles across the continent. It disturbs the circadian day-and-night rhythm of living organisms, including humans, with negative health effects on species and whole ecosystems.

The study focuses on three major negative impacts: the suppression of melatonin, the phototaxic response of insects and bats, and the visibility of stars in the night sky.

“When we turn the streetlights on, we deprive our body of the hormone melatonin and disrupt our natural sleep pattern,” explains Alejandro.

Most insects and nocturnal animals are extremely sensitive to light. Not only moths, but almost all the bat species that bread in Europe live in regions where the spectral composition of nighttime lighting has become whiter. Scientists claim that this has a direct impact in their ability to move and react to a light source, also called phototaxic response.

Along with other animals, humans have long used the stars for navigation. In modern times, a worsening in the visibility of stars goes beyond geolocation and astronomical observations. Scientists are concerned that not seeing the night sky may have negative impacts on people’s sense of ‘nature’ and their place in the universe.

While the LED lighting revolution promised to reduce energy consumption and improve human vision at night – and with it, a sense of safety –, the study shows that overall emissions have increased. Paradoxically, the cheaper and better the lighting, the higher is society’s addiction to light.

The paper speculates with the existence of a ‘rebound effect’ in outdoor lighting, where power efficiency and associated cost reduction increases the demand for lighting and diminishes any efficiency gains.

Urban nights in Europe are growing a little darker though. Pushed by a looming energy crisis, wasted light is financially more painful. Several European cities are switching off the lights – from Madrid to Paris and via Berlin, hundreds of monuments and public buildings are no longer illuminated at night.

These initiatives are all part of efforts to reduce energy consumption by 15 percent, following plans laid out by the European Commission last month. The objective is two-fold: to foster a resilient and more autonomous economy ahead of the winter, and to responsibly reduce carbon emissions.

Light changes everything

 

I’VE always been fascinated by light. Or perhaps, to put it more accurately, by the lack of dark compared to the perpetual electronic daylight most of us now live in and accept as the norm.

It may have been an early interest in astronomy and growing up under big Fenland skies that first prompted this lifelong interest. The stunning wonder of the heavens in a gloriously dark and primitive sky that, in those days, was hardly touched even by artificial satellites.

A decade or so ago I started taking a more professional interest in new types of lighting and its potential impacts on life in general and human health in particular, attending some international lighting conferences and writing about the subject more widely through my work as a freelance journalist.

I had a feeling deep inside that something about our modern forms of light and our more recent headlong dash to LED technology wasn’t quite right - and yet I couldn’t quite put my finger on it.

Of course, I was as keen as anyone to promote better dark skies by removing as much of the unnecessary light pollution as possible that now pervades our life after darkness falls. I was also a keen supporter of the fledgling environmental movement so, like most of us, I quickly bought into the industry-led narrative about LED lighting, its energy-saving properties and how good it would be for our planet.

Was there a downside? On the face of it there didn’t appear to be one and it seemed we were all left with little choice but to purchase vastly more expensive LED technology light bulbs. Okay, so the cost was a bit steep compared to the incandescent bulbs we were all replacing but if we were saving Earth in the process surely that was a price worth paying?

But all along the light sensitive ‘eyes’ in my gut were posting warning signs about the slow but inexorable creep of modern-day LED lighting.

In the past few years they might have darkened the heavens in a few locations though that might be more the result of councils up and down the country switching off lighting to save money.

What we might have saved in energy consumption on an individual light has likely more than been replaced by the massive increase in the quantity of lighting installations of all kinds. In reality, LEDs have led to a pandemic of uncontrolled and excessive lighting inside our homes, on public buildings, on transport and on the roads.

Driving home after dark the other evening, I was momentarily blinded by the dazzling headlights of an oncoming car. At first I thought the driver had mistakenly left his lights ‘on beam’ but then I realised this excessive brightness was a new normal for night-time driving. These were just the ultra-bright LED headlights now installed as de facto standard on every new car.

I fear I am not alone in finding overly bright vehicle headlights an increasing driving and road safety problem - and not always just at night, sometimes in the daytime too.

It seems our lighting designers - whether for street “function”, inside the home or on motor vehicles - have run with the excitement of LED technology merely because it was new and the latest thing.

In the process little thought has gone into its intense luminosity, blue-white colour balance or the fact that LED light is acutely directional, more akin to a laser than a conventional light source with excessive glare, a huge increase in light intensity at the centre and a very sharp cut-off.

The UK is not alone. Populations around the world have readily embraced these new forms of light, often unwittingly and without due process to its effect on our bodies and the environment. If I have learnt one thing whilst studying this issue over recent years it is that light is not just light.

Certainly the more intense blue-white light of lower cost high lumen LEDs is potentially damaging for us whether in the home or outdoors - and, treated without due caution, may actually turn out to be a lot worse than our now rejected traditional forms of incandescent lighting.

In her recently published book (Incandescent, September 2019), journalist Anna Levin throws her own spotlight on the transforming colour and tone of our everyday environments. “Light is changing, dramatically. Our world is getting brighter - but is brighter always better?” she asks.

The thrust of Levin’s book is that natural light (and dark) is fundamental to almost every aspect of life on Earth, interacting with humans and animals in profound yet subtle ways. “We mess with the eternal rhythm of dawn-day-dusk-night at our peril,” says Levin. “But mess with it we have, and we still don't truly understand the consequences.”

She claims that technology and legislation have crushed our previously warm, incandescent lighting in favour of harsher, often glaring alternatives.

And there is the irony. Since regulations were passed introducing legislation banning incandescent lamps, domestic energy consumption has actually risen and so, according to the UK Department for the Environment, there has been no overall saving.

In recent years there can be no question that our night-time world has been rapidly infiltrated by a voracious predator - an un-natural form of light that is both seen and unseen at the same time.

Incandescent is a well-researched and written book, with accessible analysis and explanations supported by technical details about LED lighting’s potential impact on human health and the wider environment. It throws an intriguing new light on an unanticipated problem that is only now becoming recognised.

Some useful links:
Anna Levin - Incandescent
LightAware - charity & support
Soft Lights - lighting with thought 
Clive Simpson - Writer & Editor

Dazzled by LEDs

DO you still enjoy driving at night? Well, if you don’t and - apart from the ever-increasing traffic volumes - there might be another, initially less obvious, reason.

Last week Public Health England warned that high levels of blue light in LED street lighting can be uncomfortable and are known to cause retina damage. The same goes for the new generation of ultra bright LED vehicle headlights.

The executive agency of the UK govrnment's Department of Health also suggests that daylight-running lights on cars can lead to drivers being dazzled by oncoming vehicles with the risk that they may not see hazards until too late’ - a problem that can be exacerbated by misty conditions and fog.

Right across the UK - and with little heed to the mounting medical evidence against them - LED street lights have been used to replace older forms of street lighting as they are much cheaper to run, easier to control and can have less general light dispersal.

But all this comes at a price and John O’Hagan of Public Health England is now warning that councils and vehicle manufacturers should be considering social and health factors as well as their budgets.

Writing in the chief medical officer’s annual report, he says that if local authorities have been replacing mercury and sodium street lights with LEDs purely on the basis of energy efficiency and cost it is possible to end up with installations that may not be “fit for purpose”.

“Some streetlight luminaires have LED sources that can be seen physically projecting below the luminaire, becoming a glare source or light pollution,” explains. “The light spectrum may also be enriched in the blue, which may be beneficial for keeping drivers alert will be uncomfortable for many people. High levels of blue light are known to cause damage to the retina in the eye.”

O’Hagan acknowledges that LEDs can be provided in a range of colour temperatures and that “warmer colours” are more appropriate for populated areas.

Research assessed by Public Health England and others also raises concern about the variable illuminance of LED light sources which, at the extreme, switch on and off 100 times per second.

“In such circumstances rotating machinery, which could include the blades on a food mixer, may appear to be stationary if the rotation rate matches the modulation rate or is a multiple of it,” suggests O’Hagan.

This frequency can also result in headaches, migraines and feelings of malaise in those sensitive to light modulation.

As blue-rich white light continues to spread across the country like wildfire pollution, a considered national lighting policy is urgently needed is to minimise harmful consequences for humans and wildlife.

Street lights and vehicle lights with a far too high CCT (Correlated Colour Temperature) values (ie, well above 3000 Kelvin) are becoming commonplace.

Public Health England and the Campaign for Rural England are now among the growing number of international organisations calling for lower CCT levels and warmer colour temperatures to help prevent glare, discomfort and potential medical problems in humans, as well as reducing adverse affects to wildlife.

Seeing the (LED) light

There is something of an evangelical fervour about the way public lighting authorities are installing new LED lighting on our streets and roads across the UK.

But in the rush to cut power consumption and save money long-term, our public authorities and the lighting industry itself may be turning a blind eye to serious health risks posed by this new technology.

Increased risks of cancer, diabetes and cardiovascular disease is hardly being championed by the lighting companies that market and promote the benefits of light emitting diodes (LEDs).

A report released this summer by the American Medical Association (AMA) Council on Science and Public Health confirms suspected impacts to human health and the environment caused by excessive amounts of blue light.

‘Human and Environmental Effects of Light Emitting Diode Community Lighting’ presents significant implications for the ongoing, worldwide transition to LEDs as the outdoor lighting technology of choice.

While it supports the use of LED lighting in order to reduce energy consumption and the use of fossil fuels, it also recognises that some LED lights are harmful.

The report details findings from an increasing body of scientific evidence that implicates exposure to blue-rich white light at night to increased risks for cancer, diabetes and cardiovascular disease.

Blue-rich white LED street lighting can be five times more disruptive to our sleep cycle than conventional street lighting, according to the report.

Recent large surveys have documented that brighter residential night-time lighting is associated with reduced sleep, impaired daytime functioning and a greater incidence of obesity.

As a result of a potential risk to public health from excess blue light exposure, the AMA report encourages attention to optimal design and engineering features when converting from existing lighting technologies to LED.

These include requiring properly shielded outdoor lighting, considering adaptive controls that can dim or extinguish light at night, and limiting the correlated colour temperature (CCT) of outdoor lighting to 3000 Kelvin (K) or lower.

Colour temperature is a measure of the spectral content of light, and higher CCT values indicate a greater amount of blue light.

"This is a timely and important policy statement by the AMA," says Richard Stevens, a cancer epidemiologist at the University of Connecticut School of Medicine and co-author of the report.

"As with most new technology, everyone is enamoured at first because it's so great and does so much for us, but the downsides eventually become apparent. Electric light has great attributes, but we now realise, when poorly used and abused, there are also many problems."

The AMA findings also underscores the fact that detrimental effects of blue-rich LED lighting are not limited to humans.

 “Other species are just as vulnerable to disruption of their circadian rhythms as are humans, and often more so,” explains Travis Longcore, Assistant Professor of Architecture, Spatial Sciences, and Biological Sciences at the University of Southern California.

“Those impacts and others can be reduced by limiting blue-light emissions. Policy makers, government officials, and the American public now have the science and the imprimatur of the AMA to insist that LED installations be designed to reduce impacts on wildlife and human health.”

The issue is an important one and we should have the confidence that it is being properly addressed by those in the UK responsible for our night-time lighting - including local authorities, public bodies and the lighting industry itself.

Light of the world

Experts from around the globe gathered at Leicester’s De Monfort University in the UK this week to discuss ‘artificial light’ and how it is not only affecting the world we live in but is also increasingly helping define it.

The fact that light at night affects us adversely more than we might think is not something many of us give a second thought to - let alone consider it necessary to be discussed at an international conference.

But those at ALAN 14 - the second ‘Artificial Light at Night’ annual conference - had a significantly different take and highlighted a number of concerns that need to be taken seriously.

The scientists and researchers had travelled from the different parts of the UK, Ireland, the United States, Europe and Australia to present their findings on light-related topics and related research across the fields of health, biology, pollution, ecology, technology and design.

ALAN 2014 examined the use of artificial lighting at night in all its forms, as well as the spectrum of adverse effects that artificial light at - known collectively as light pollution - night may cause.

The theme coming through loud and clear is that society at large is barely beginning to recognising that such liberal and indiscriminate use of illumination is at a mounting cost to both the environment and ourselves.

Interestingly, an increasing number of scientific studies are now seriously questioning the long-held premise that humans are largely immune to the effects of artificial light at night.

Research is now confirming that artificial light - even in quite small doses - disrupts sleep, confuses circadian rhythms and impedes the production of the hormone melatonin.

All of which is bad news if the consequences of excessive exposure to light at night really do include an increased risk for obesity, diabetes, cancer and cardiovascular disease.

Back in 2012 the American Medical Association (AMA) called for more research into the risks and benefits of occupational and environmental exposure to artificial light at night and for the introduction of new lighting technologies at home and at work that minimise circadian disruption.

Technological advances such as LEDs (light-emitting diodes) have improved the potential for better targeted lighting - but for now they are often brighter and more intrusive than the old lights they are replacing.

Much of our modern light - whether from TVs, computer screens, smart phones and electronic gadgets or from outdoor lighting of one form or another - is also ‘blue’ rich and so proves even more disruptive to the 24 hour biological process that regulates the body's functions.

According to conference organiser Prof Martin Morgan-Taylor, of the School of Law, De Montfort University, Leicester, and a Legal Advisor to the UK Campaign for Dark Skies, the physiological effects caused by lighting may be similar to noise.

"Admittedly, there are comparatively few studies as yet on the problems caused by lighting, but lights can and do wake people up, just as does noise," he said.

"Moreover, with light it appears that the subject does not need to be fully awakened to suffer the same negative effects as someone who has been deprived of sleep altogether."

This means that people's health can even be adversely affected by ‘security’ floodlighting and, what the Chartered Institute of Environmental Health (CIEH) refers to as, ‘light briefly turning on and off' during the night.

Prof Morgan-Taylor stated the research concerning cancer risks does not restrict itself to lighting that wakes the subject because risk factors are akin to the levels of night-time light entering a bedroom.

Paul Marchant, of Leeds Metropolitan University, questioned the widely held perception of ‘improved’ (brighter) lighting is always beneficial in reducing road accidents and crime.

The generic objection to this - based on the premise that light equals protection and darkness represents danger - is that we need all this light for safety and security, he said.

Such common belief goes a long way to explain why many supermarkets, petrol station forecourts and car parks, as well as our own driveways and yards, are lit more than ten times as brightly as they were just 20 years ago.

"In fact, the issue of light at night and safety is rather more complex, and there is little compelling evidence to support widespread such mis-assumptions," he said.

"Ever-brighter lights can, for example, actually diminish security by casting glare that impedes vision and creates shadows where criminals can hide."

Emma Marrington, CPRE Dark Skies campaigner and author of ‘Shedding Light’, a survey of local authority lighting policies, said some local authorities are taking steps in the right direction.

She said the research had revealed no evidence to support the fear that adjusting or dimming street lights impacted on public safety.

"We urge councils to do more to control lighting in their areas and ensure that the right lighting is used only where and when it is needed."

"We're not advocating changes where they're not appropriate - but why shine bright lights on residential streets, quiet roads and open countryside throughout the night when they are not needed?"

The consistent theme emerging from ALAN 14 was that there are many different aspects to artificial light at night and the effects on our well-being, ecology and life in general are only just beginning to be understood.

We will, no doubt, continue to tinker with the natural world and all its variances, and the exponential growth of artificial light in our homes and across the planet shows now time of dimming yet.

In the meantime, conferences like ALAN will gradually produce evidence in an attempt to redress the balance.

And one day there may come a time of new enlightenment - when we release that at certain times of the day we need dark more than light.


The conference was hosted by Leicester De Montfort Law School, De Montfort University, and co-organised with the EU COST Action LoNNe (Loss of the Night Network) in association with the International Dark Sky Association. My thanks to Martin Morgan-Taylor and Katie Scott.

LED lighting's dark side

New LED street lighting being installed by councils throughout the country to save money and cut carbon emissions could mean more sleepless nights and ultimately be bad for our health.

A study by the Campaign for the Protection of Rural England (CPRE) says some eco-friendly low-energy LED (light emitting diode) street lighting creates unnecessary glare and might have serious effects on people’s well-being.

Light pollution expert Martin Morgan-Taylor has called for more research into which wavelengths, levels and durations of lighting pose health threats - and how this compares with modern lighting practices.

The lecturer - from Leicester’s De Montfort University - says medical research is increasingly linking LED lighting with more serious health issues such as cancer and depression.

"Artificial lighting is known to have negative effects on human health and well-being if sleep is disrupted by bright light shining into bedroom windows," he said.

"What we know is that ‘white’ or ‘blue-rich’ lighting - which mimics natural daylight - is being increasingly used at night.

"This type of light suppresses the production of a circadian rhythm hormone called melatonin, which is believed to be a powerful anti-oxidant that helps to ward off some cancers," he said.

The CPRE report, ‘Shedding Light – a survey of local authority approaches to lighting in England’ is the first piece of research to ask councils how they control light pollution.

Councils are urged to give ‘careful consideration’ to the type of LED lighting they use and weigh the potential impacts that higher temperature blue-rich lighting has on ecology and human health.

The report says authorities across England could be doing more to reduce the impact of light pollution and be saving hundreds of thousands of pounds a year in the process by using dimming schemes.

It also urges councils to preserve dark skies by having a ‘presumption against’ new lighting in existing dark areas and preventing ‘inappropriate and badly designed development’ that masks views of the night sky.

But according to the survey of 83 local authorities fewer than two thirds of councils in England are actively seeking to minimise the impact of bad lighting - despite recent changes to planning laws which encourage them to do so.

The CPRE also recommends new street lighting should be tested ‘in situ’ before schemes are rolled out across wider areas to ensure that it is the minimum required for the task and does not cause a nuisance to residents.

Street lighting in England costs councils around £616m a year and can account for up to 30% of their carbon emissions.

The CPRE study reveals that despite the number of people living with severe light pollution around the country growing more than a third of councils have no formal policy in place.

Almost half of councils responding said they were involved in dimming street lights in their areas and a third say they are now switching off street lights - typically between midnight and 5am.

The research found dimming schemes are significantly more popular with residents than switch off schemes - with 68 per cent of respondents saying local communities had been very supportive.

Some council schemes to replace old-style sodium ‘orange’ street lighting with new LED lamps have attracted criticism from nearby residents.

Last month people in a west London borough complained that new LED street lamps were so bright they were no longer getting a good night's sleep.

Hounslow council started using the lights as part of a multi-million pound improvement scheme but people living close to the new LED lighting described it is ‘like living on a floodlit soccer pitch’.

Elsewhere, Leicester city council is updating 32,000 of its 37,000 street lights as part of a commitment to reduce the council's carbon footprint by 50% before 2025.

The three year £13.9m project began in March 2013 and will contribute an estimated saving of 5,350 tonnes of carbon emissions per annum.

It includes a Central Management System (CMS) for remote control of lighting levels in specific areas, allowing dimmed lighting, for example, in the early hours before dawn.

The council says replacing its existing stock with LED lighting will reduce energy usage and carbon emissions by over 40% compared with current levels, saving electricity charges (at 2013 prices) of £0.84m a year.

Using a CMS should provide a further 17% reduction, increasing the overall savings to 57% of current energy usage and carbon emissions, and slashing a total of £1.2m off its annual electricity bill.


Aerial view of Leicester city centre at night clearly showing the streets
where new white LED lighting has already been installed.

Other councils are, however, taking a more cautious route. In Essex, the streets have been equipped with one of the world’s largest wireless street lighting control systems.

Around 125,000 of the county’s street lights have been wirelessly linked, allowing centralised control and fault detection.

The council expects to reduce the energy cost of street lighting by around £1.3 million per year and to cut annual carbon emissions by over 8,000 tons.

Earlier this year Trafford council in Manchester delayed its £9.3m scheme to replace all its 27,000 street lights after a resident threatened High Court action.

Simon Nicholas, a chartered engineer and businessman, raised concerns that new LED lighting had the potential to cause health problems.

"We're breaking new ground here and new evidence is emerging all the time," he said. "The council has not fully taken these studies into account."

Mr Nicholas claimed some councils are not looking at the bigger picture ."LEDs are currently on an exponential curve in terms of development," he said.

"In five years’ time we may well have really good LED street lights. Anyone charging in now is making a huge mistake."

Emma Marrington, CPRE Dark Skies campaigner and author of the ‘Shedding Light’ report, said: "Many local authorities are taking steps in the right direction but much more can be done.

"We urge councils to do more to control lighting in their areas and ensure that the right lighting is used only where and when it is needed."

She said the research had revealed no evidence to support the fear that adjusting or dimming street lights impacted on public safety.

"We're not advocating changes where they're not appropriate - but why shine bright lights on residential streets, quiet roads and open countryside throughout the night when it's not needed?

"Genuine dark starry nights are becoming harder and harder to find which is why councils should take action to control it now. Light pollution blurs the distinction between town and country, ruins the countryside's tranquil character and denies us the experience of a truly starry sky."

The Lighthouse Keeper is written by Clive Simpson - for more information, commission
enquiries or to re-publish any of his articles click here for contact information

You are what you sleep

Margaret Thatcher was once famous for promoting the adage that she could thrive and work effectively on only a few hours sleep per night.

And, though there are exceptions to every rule, for the large majority of us it is not the same - we ignore sleep at our peril.

A report today for the BBC's ‘Day of the Body Clock’ asserts that society has become ‘supremely arrogant’ in ignoring the importance of sleep.

Leading researchers from Oxford, Cambridge, Harvard, Manchester and Surrey universities have warned that cutting back on sleep is leading to serious health problems.

Scientists have warned that our modern life and 24 hour society mean many people are now ‘living against’ their body clocks with damaging consequences for health and well-being.

We all know that lack of regular sleep can affect our mood, vitality and energy levels. But cancer, heart disease, type-2 diabetes, infections and obesity have also all been linked to reduced sleep.

Prof Russell Foster, from the University of Oxford, told the BBC that people are now getting on average between one and two hours less sleep a night than 60 years ago.

"We are the supremely arrogant species because we feel we can ignore the fact that we have evolved under a light-dark cycle,” he said.

“What we do as a species, perhaps uniquely, is override the clock. And long-term acting against the clock can lead to serious health problems.”

Regular readers of ‘The Lighthouse Keeper’ will know that the natural rhythms of life, and of light and darkness, have been discussed at frequent intervals.

Harvard University’s Prof Charles Czeisler confirmed that light is the “most  powerful synchroniser” of our internal biological clocks.

He said energy efficient light bulbs as well as TVs, smart phones, tablets and computers had high levels of light in the blue end of the spectrum, which is "right in the sweet spot" for disrupting the body clock.

“Light exposure, especially short wavelength blue-ish light in the evening, will reset our circadian rhythms to a later hour, postponing the release of the sleep-promoting hormone melatonin and making it more difficult for us to get up in the morning.

“It’s a big concern that we're being exposed to much more light, sleeping less and, as a consequence, may suffer from many chronic diseases.”

In ‘Blinded by the night’ I noted that an increasing number of scientific studies were questioning the long-held premise that humans are largely immune to the effects of artificial light at night.

Today, or to be correct, tonight, we have levels of light hundreds and thousands of time higher than the natural level during the night – and light pollution is currently rising by a general average of 20 percent a year.

What is happening in the streets outside our homes is not always within our control. But we can take more personal responsibility when it comes to the light behind closed doors.

In his book ‘A Great Day at the Office’, Dr John Briffa discusses sleep as one of the strategies to help maximise our energy and performance levels.

“Light exposure in the day promotes better sleep but it may have the reserve effect late in the evening,” he says.

“In one study, light exposure from room lighting was found to delay meltonin exposure by about 90 minutes. Turning room lighting down, or perhaps off altogether (and using dimly lit lamps) during the evening may help sleep.”

I covered the topic of how excessive light at night affect our sleep and health more extensively in ‘Early morning birdsong’.

If you don’t sleep too well at night then it is probably a good idea, according to Dr Briffa, to be mindful of the potential impact of evening light levels on sleep.

TVs, laptops, tablets and smart phones - with their blue-rich light - can all suppress melatonin function too so avoiding the use of these within a couple of hours of bedtime may be a helpful - though impossibly hard - tactic to implement.


The Lighthouse Keeper is written by Clive Simpson - for more information, commission
enquiries or to re-publish any of his articles click here for contact information

Street lite

Photo: Clive Simpson

On the road home the night-time light has changed. We are in the heart of South Lincolnshire’s farming landscape approaching the interestingly named hamlet of Cowbit, midway along the old main road between Crowland and Spalding.

The road bends gently along a raised bank, originally built to stave off flooding from the plain of the nearby River Welland, and the lights cut through the night like harbour beacons around a vast concave seashore.

Tonight, I notice that the familiar curve of orange-glowing street lights - picking out the homeward route ahead against the flat Fenland horizon - have been replaced by the cool and dazzlingly bright light of modern LED technology.

Definitely cheaper to run - and therefore more energy efficient - these lights are an increasing part of our night-time scenery up and down the country.

But after five miles of driving along dark, unlit roads the clinical brilliance comes as a shock to night-adjusted eyes.

All this is part of local authority plans - in this case Lincolnshire County Council - to replace and update all our traditional street and road lighting over the coming years.

Energy and cost savings aside, the new kind of lighting is defined by its brightness and intensity, like spotlights on a West End stage show. But at least there is less apparent spillage into the heavens above.

LED luminance is potentially much more controllable than traditional sodium light and so one might reasonably ask the question of our lighting engineers - is it necessary (and even safe for approaching motorists) to have these beams on full luminance at the point where we suddenly cross from dark to light?

There are increasing complaints from across the country where such shiny new lights - installed in normal streets and cul-de-sacs - have cut through curtained windows to illuminate living and sleeping spaces, playing havoc for those in the vicinity.

Bright is not always best for human health and there is obviously a need for more research into the potential risks from the glare of LED lighting.

Already it is well documented that exposure to LED light suppresses melatonin production by up to five times more than exposure to sodium-based light, disrupting our biological clocks and affecting sleeping and rest periods.

Recent research in Spain has indicated that long-term exposure to LED street lighting could, as a result of the high levels of blue band radiation, cause irreparable harm to the retina of the human eye.

And last year a report by the French government stated that a luminance level higher than 10,000 cd/m2 causes visual discomfort whatever the position of the lighting unit in the field of vision.

As the emission surfaces of LEDs are highly-concentrated point sources the luminance of each individual source can be 1000 times higher than discomfort levels, making this intense glare a tangible problem.

Which brings me to reflect on the familiar orange, phosphorescent glow that has been part of our night time scene for so long.

Despite its intrusion, particularly into the night sky above, will we come to rue the day of its disappearance?

At the ending of DH Lawrence’s ‘Sons and Lovers’ the book’s central character Paul Morel is drawn ‘towards the city's gold phosphorescence’.

Signifying corruption and decay, ‘phosphorescence' was to become one of Lawrence’s jargon words in subsequent novels.

‘But no, he would not give in. Turning sharply, he walked towards the city's gold phosphorescence. His fists were shut, his mouth set fast. He would not take that direction, to the darkness... He walked towards the faintly humming, glowing town, quickly.’

For Paul Morel, the ending was something of a false epiphany. That 'gold phosphorescence' was an emanation of the mechanised life of the industrialised world - the glow of false promise.

In the end Paul’s tragedy was that he was only able to move in the direction of the city, humming not with the natural activity of a hive, but with machinery, and glowing not with sunshine and warmth but with the ghastly phosphorescence of street lamps and decay.

That familiar orange glow in our night-time skies does indeed represent something of the past, industrial age - whereas the clinical, white light of LEDs is symbolic of the modern, sanitised world.

Our continued attempts to tame and banish the natural darkness and rhythms of life only serve to deepen the shadows around us. What, I wonder, would Lawrence have made of this?

The Lighthouse Keeper is written by Clive Simpson - for more information, commission enquiries or to re-publish any of his articles click here for contact information

Early morning birdsong

Lighthouse on the cliff tops of Cromer, Norfolk.                                       Photo: Clive Simpson

Are you sleeping well on these long end of winter nights? If not then part of the answer may be in how dark your bedroom is.

As we travel through winter, with its emerging hint of longer days and promise of spring, it is appropriate to revisit the theme of some previous blog articles about night, darkness and the effect of artificial light on our modern lives.

The other morning I awoke midway through the night at around 3 am to hear birdsong outside. Normally a welcoming sound but at that hour, and with dawn still some four hours away, a little disconcerting. 

Birds singing during the ‘night’ is no longer such an infrequent occurrence. It is a somewhat troubling development and perhaps an indicator of wider factors at play. 

The birds it seems are often duped by our brightly lit streets, on-off ‘security’ lights and other forms of night-time illumination and general light pollution, into thinking daylight has arrived early.

And here’s the thing. All of us, birds included, are hard-wired to sleep in darkness, not in bedrooms full of light, computer monitors, digital alarm clocks or TV stand-by lights.

Chronic exposure to light at night is bad and, to understand why, we need to look into the past. Prior to the end of the Stone Age, humans were largely exposed to just two different kinds of natural light.

During the day we had the sun, while at night we had the moon and the stars, and perhaps the light from campfires. The binary day/night pattern was unrelenting, and our biological programming followed suit.

So why can't you get a good night's sleep? The problem is that many of us probably don't realise what makes us fall asleep in the first place. 

Compared to our ancestors our bodies’ circadian rhythms now also have artificial lighting at night (LAN) to contend with. Indoor lighting may be considerably less powerful than sunlight but it is certainly many orders of magnitude greater than star and moonlight. 

Melatonin suppression is key to understanding much of why LAN is bad for us, particularly in the winter months of the northern hemisphere.

This workhorse biochemical is produced at night when it is dark by the brain's pineal gland  to regulate our sleep-wake cycle. It lowers blood pressure, glucose levels and body temperature — key physiological responses responsible for restful sleep. 

The part of our brain that controls the body’s biological clock is known as the Suprachiasmatic Nucleus (SCN), a group of cells in the hypothalamus which respond to light and dark signals. 

The optic nerves in our eyes sense light and transmit signals to the SCN telling the brain when it is time to wake up, which also kickstarts other processes, like raising body temperature and producing hormones such as cortisol. 

Normally our cortisol levels are relatively low at night - allowing us to sleep - and higher during the day, allowing for the stabilisation of energy levels and the modulation of immune function. 

But LAN unnaturally elevates cortisol levels at night, which can then disrupt sleep and introduce a host of problems relating things like body-fat levels and insulin resistance. It also contributes to sleep debt and can disrupt the regulation of appetite.

If, on the other hand, our rooms are properly dark at night there is no optic signal to the SCN, so our bodies pump out the much needed melatonin. 

Light exposure during the previous day can also affect melatonin levels - studies have shown that exposure to bright room light before bedtime shortens melatonin duration by about 90 minutes compared to dim light exposure. In addition, exposure to room light during usual hours of sleep suppresses melatonin levels by more than 50 percent. 

So, even before you hit the hay, the light in your bedroom may be causing you problems. With the introduction of tablets (not the sleeping kind), smartphones, and energy-efficient LED light bulbs, it's an issue that's only getting worse. 

And just to add insult to injury, many modern LED (light-emitting diode) devices emit blue light which is especially good at suppressing melatonin. This is because melanopsin — a photo-pigment found in specialised cells of the retina involved in the regulation of circadian rhythms — is most sensitive to blue light. 

Regrettably, all this hormone and biochemical disruption is creating downstream effects — and studies are now showing correlations with weight gain problems, the incidence of cancer, depression and adverse effects on the immune system.

Essentially we need to keep our bedrooms as dark as possible and avoid blue light before sleep. 

You might want to think about this next time you leave even the dimmest lights on in your bedroom overnight — including your clock radio and the light that bleeds in through the curtains from nearby street lights. 

Why not try removing electronic equipment from the bedroom and using dimmer lights before before you turn in, as well as refraining from viewing TV, smartphones and computer screens for up to an hour before bed?

And if your bedroom is affected by artificial light from outside (and blackout curtains don’t do the trick) speak to your local council about street light shielding, and maybe your neighbour about realigning any problematic external floodlights.

Oh, and while we’re at it, switch off that bl**dy lighthouse! Sleep well, zzz zzz.

The Lighthouse Keeper is written by Clive Simpson - for more information or to get in touch click here