Friday, 30 May 2014

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
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  1. The odd thing is that it ought to be easy to dim LED lighting as the night gets darker

  2. Absolutely - but they don't seem to understand this. The same goes for car manufactuers and their over-bright LED lights on new cars.