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Artificial lighting at night is harmful to human health
Last reviewed: 01.07.2025
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In the modern world, people live in the light almost around the clock. At night, a huge glow shines over large cities. According to experts, over the past 150 years, nights in megalopolises have become much brighter than before.
World experts discussed the problem of light pollution and its ecophysiological consequences. The experts tried to shed light on the degree of danger and damage caused by artificial lighting at night.
This is a map from the American NOAA agency. Yellow and red indicate areas with an increased "light" pollution index in 1992-2003. They coincide with the location of the most populated areas and large urban agglomerations.
"The most important thing for us is to understand how dangerous artificial lighting can be for humans and the environment. The American Medical Association recently approved a new program that will allow scientists to conduct detailed studies of the effects of night light and identify the adverse effects it has," says University of Haifa professor Avraham Haim, a leading expert on light pollution.
The main sources of light in large cities are street lighting, billboards that glow 24 hours a day, and spotlights. Most of the light mass is directed upwards and creates a kind of light dome over the city. This is largely due to the fact that street lighting has an incorrect system, which leads to irrational use of energy.
The bright glow effect is added by dust particles dispersed in the air, which additionally reflect, refract and scatter light.
Light pollution can significantly hinder astronomical observations and harm the ecosystem by wasting energy and increasing greenhouse gas emissions.
In addition, artificial lighting is dangerous for the vital functions of living organisms. The growth cycle of plants suffers from this. Many insects and animals that are active only at night also suffer from this effect. Light-emitting diode sources are especially harmful to nocturnal creatures.
During the conference, Professor Haim presented the results of one of his studies, which showed the adverse effects of night light.
The scientist's test subjects were rats that were exposed to chronic light exposure. It turned out that the animals had changes in the psycho-emotional and behavioral sphere. The specialist associates this with the hormone melatonin, which is produced at night and the production of which is inhibited by light exposure. According to the scientist, the greatest harm is caused by energy-saving lamps, which are capable of inhibiting this process more than ordinary ones.
"We think that the human body reacts to light in a similar way. The greatest "light" loads are received by young people, who practically never tear themselves away from the screens of smartphones, laptops and tablets - all these gadgets surround modern people everywhere. We cannot know how night illumination will affect us in 20 years, but there are assumptions that there is little good in this," says the professor.
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