(ORDO NEWS) — LEDs consume much less energy than traditional HID lamps, which should reduce greenhouse emissions. But at the same time, LED lighting threatens the health of residents and destroys local ecosystems in cities and villages.
Researchers from the University of Exeter (England) studied the spectrum of night lighting in Europe and came to a disappointing conclusion: the conversion of street lamps to LEDs does not seem to justify itself in environmental terms.
The artificial light has become bluer, which is deteriorating the quality of sleep in humans and declining populations of nocturnal insects.
Street lighting on white LEDs has been actively introduced in a number of European countries since 2014 instead of the previous sodium and fluorescent lamps.
Such LEDs produce 200-300 lumens of light output for every watt of energy used, while sodium lamps produce 100-150 lumens per watt, and fluorescent lamps only 50-100 lumens per watt (incandescent lamps: 12-16 lumens per watt).
At the same time, the resource of LEDs reaches 100 thousand hours of operation (usually 30-50 thousand hours) compared to 16-18 thousand hours for sodium lamps and 10-20 thousand hours for fluorescent lamps (an incandescent lamp can work for about a thousand hours).
Thanks to this, LED lights are significantly cheaper to operate, although the prices for the LEDs themselves are usually higher than for gas discharge lamps.
High energy efficiency reduces the need for energy for lighting and, as a result, reduces the greenhouse emissions of power plants. This fully fits into the European course towards “green” energy and the fight against climate change.
However, the light spectrum of white LEDs is shifted from yellow, which is characteristic of the Sun and gas discharge lamps, to blue. Research shows that this is not very good. Blue light suppresses the production of melatonin, which is responsible for the sleep-wake cycle (circadian rhythm) in humans and animals.
British ecologists decided to assess the scale of the problem and analyzed the spectral maps of night illumination of European cities, obtained with the help of the ISS. They clearly show that in 2012-2013 street light in European cities was predominantly white-yellow due to sodium lamps.
Between 2014 and 2020, the spectrum of urban and rural light has indeed shifted towards blue. The strongest was in Italy, Romania, Ireland, Spain and the UK, which led to a decrease in the production of melatonin in people and animals in these countries.
Whereas Austria and Germany still use sodium lamps with their yellowish light for most street lamps.
Darren Evans, professor of ecology and conservation at Newcastle University, was not involved in the study, but confirmed his colleagues’ concerns. His own work has shown a sharp decline in the population of nocturnal insects in English cities, where more than half of the street lamps are powered by LEDs.
This destroys food chains and threatens to completely reshape urban and rural ecosystems. According to Darren Evans, the UK authorities did not predict well the consequences of switching to white LED lighting.
Especially for the health of people who, due to blue street lighting, can sleep worse and experience insomnia more often.
Ecologists offer several ways to solve this problem. For example, you can dim the lights at night. Or change the bandwidth of LED lamps to return the emission spectrum to the yellow region.
The authorities of some British municipalities do this, and according to Darren Evans, this practice should be expanded to other regions and countries.
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