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Researchers from the Complutense University of Madrid and the University of Exeter have used images obtained with digital cameras by astronauts from the International Space Station and the American Suomi NPP satellite to measure the growth of light pollution in Europe . Their work made it possible, for the first time, to provide realistic information on the growth of light pollution over a large territory. Until now, the use of Space Station images has been limited to small areas, such as cities.
They were thus able to map the variation in the spectral composition of lighting across Europe for 2012-2013 and 2014-2020. These images show a generalized regional spectral shift, from that associated primarily with high pressure sodium lighting to that associated with wide white light-emitting diodes (LEDs) and higher blue emissions, a trend that greatly increases the risk of adverse effects on ecosystems. For this reason, the study highlights the importance of assessing the impact of exposure to artificial light at night, especially in the blue spectrum, Complutense University reports in a statement.
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Light contamination
“We are seeing the replacement of lighting in our cities and highways from high pressure sodium (HPS) lamps to LED fixtures. While the former are orange, the newer ones are, for the most part, white due to their blue component in the spectrum. The changes to LEDs are driven by their energy savings and are an opportunity to reduce light pollution whether new fixtures are designed to light more efficiently and use low-blue LEDs”says Jaime Zamorano, professor of the Department of Earth Physics and Astrophysics of Complutense and director of the thesis of Alejandro Sánchez de Miguel, first signatory of the new study, which was published in the prestigious journal Scientists progress.
“As expected, there is a measurable shift to bluer fixtures. Transforming these color images into environmental impact maps indicates that the risk of adverse effects on ecosystems is increasing.”completes Zamorano, in statements collected by , in statements collected by Science Media Center (SMC).
“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, the one with a spectrum from 380 to 450 nm, is most effective in synchronizing (or altering) this system”, comments Anna Palomar, predoctoral researcher at the Barcelona Institute of Global Health (ISGlobal), whose thesis deals with circadian disruption partly as a result of exposure to artificial light at night and its effects on human health , and who did not participate in the study.
street lighting
“The systemic shift to predominantly LED public lighting has been promoted in many European cities to reduce environmental impact. However, little is known about the changing color of light from this new street lighting and its impact on human and planetary health.Paloma continues.
“The study by Alejandro Sánchez de Miguel and his collaborators highlights the shortcomings of previous studies, which evaluated the increase in artificial light at night using nocturnal images, but without taking into account the color of the light emitted, the estimates may therefore have been underestimated”, ensures.
Impact on many species
The authors of the work also highlight the imprint that this increase in blue light can have not only for humans, but also for many other species. The article demonstrates this gradual increase in blue light levels in European cities, although further studies are needed to assess its effects on human health and suggest preventive measures.
The growth between 2012-2013 and 2014-2020 in the color green is around 11.1%. In blue, for the same period it is 24.4%. This confirms the pessimistic estimates published by the same researchers last year, based on the projection of LED lamp sales. The changes are taking place very unevenly in Europe.
In Spain it is produced a 13% increase in the percentage of blue light issued before the green light. This can have an impact on people’s health via a deterioration in the quality of sleep. It also poses a threat to ecosystems in general, in particular the study discusses the impact on moths (which are important pollinators) and bats.
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Reference article: https://www.elmundo.es/ciencia-y-salud/medio-ambiente/2022/09/14/6321c63be4d4d85d378b4588.html