“Blue Light”: In addition to a palindrome, these two words are a health concern. Our sleep-wake cycles, bedtime routine, animal behavior, and even the overwhelming spectacle of the starry sky overhead are being affected by the proliferation of blue-light LED streetlights. A study published this Wednesday the magazine Science shows for the first time the growth in Europe of this type of night lighting, whose negative consequences on people and animals are beginning to be documented.
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The research goes beyond generically warning about light pollution: it analyzes in detail the accelerated progression in the use of each type of light, differentiating between blue, green and red light waves.
The Spaniard Alejandro Sánchez de Miguel and his colleagues at the University of Exeter, in the United Kingdom, have used images obtained by astronauts from the International Space Station (ISS) to map the variation in spectral composition of lighting throughout Europe in two periods: 2012-2013 and 2014-2020. The research has as its starting point the doctoral thesis of Sánchez de Miguel himself, presented in 2015.
The data shows the progressive replacement of public lighting from lighting based on high pressure sodium (in a yellowish tone) to one using white LED lamps with higher blue emissions. The effect has been especially notable in Italy, Romania, Ireland and the United Kingdom, while Austria and Germany have been the countries that experienced the least changes.
Effect on melatonin
“There is a measurable shift to bluer fixtures. The transformation of these color images into environmental impact maps indicates that the risk of harmful effects on ecosystems is increasing,” says Jaime Zamorano, director of Sánchez de Miguel’s thesis and professor in the Department of Earth Physics and Astrophysics. of the Faculty of Physical Sciences of the Complutense University of Madrid, in statements to SMC Spain.
For this reason, the authors have reviewed several previous studies, which for years have been warning of the effects of artificial light at night on melatonin (the hormone that regulates the sleep-wake cycles and other bodily processes).
Speaking to elDiario.es, Sánchez de Miguel recalls that the issue must be treated with care and that research is still lacking: “What is clear is that exposure to blue light produces a serious loss of sleep quality even within the legal limits in force in Spain. That poorer quality of sleep has multiple impacts. From increased risk of obesity, diabetes, increased aggressiveness and glare on the roads.
Exposure to blue light produces a serious loss of quality of sleep even within the legal limits in force in Spain
Alexander Sanchez de Miguel
— Lead author of the study
Anna Palomar, a researcher at the Barcelona Institute for Global Health (ISGlobal), also comments on the research for SMC Spain: “The circadian clock regulates the proper functioning of multiple systems in the human body. The main synchronizing factor of this system is the light that enters through the retina into our eyes. Blue light, that with a spectrum of 380 to 450 nm, is the most effective at synchronizing (or altering) this system. The systemic change towards a public lighting composed mainly of LEDs has been promoted in many European cities to reduce the environmental impact. However, little is known about the change in light color from this new street lighting and its impact on human and planetary health.”
insect behavior
The research published today also warns about the effects on fauna and, specifically, on the behavior of certain insects towards light (the so-called phototaxis). Moths are especially attracted to this tone of light, with which the populations of these insects are concentrated in urban areas where they die, leaving bats and birds without food in wooded and unpopulated areas.
This has as an aggravating factor the hindrance of the pollinating function of the moths. “They are as important or more important than domestic bees,” adds Sánchez de Miguel. Fireflies also suffer, a species in which the male is attracted by the same artificial light that repels the females, which makes reproduction difficult.
Stars ‘forget’ to go out
As for the visibility of the stars, the study recalls that, along with other animals, human beings have used the sky for centuries to orient themselves. The loss of vision of the night sky, in addition to astronomical observations, can affect, according to the authors, “people’s sense of ‘nature’ and their place in the universe.”
Sánchez de Miguel considers that there is “a lot of misinformation” about LEDs: “There are many that are not as efficient. In fact, the most efficient lamps on the market are not LED, but low pressure sodium. And they are not an alternative because, in a blatant example of planned obsolescence, their main manufacturer recently stopped producing them.”
Another question that this research puts on the table is that of the debatable usefulness that traditional images obtained by satellite have been offering. These images are the ones that are usually used to measure light pollution or determine which areas are inhabited and which are not.
However, by not distinguishing between types of lighting, satellite images may end up providing a “poor or limited quantitative indicator of exposure to environmental risks associated with artificial light at night”, say the authors, who have therefore preferred to use images obtained by the ISS.
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