Lights out? The dangers of exposure to light at night

A panel of world experts discussed ‘Light Pollution and its Ecophysiological Consequences’ and shed light on the extent of the dangers and harm that night-time lighting causes, emphasising that it is the short wavelength illumination that we have come to know as ‘eco-friendly illumination’ that is causing the most harm (primarily LED lighting).

“The most important thing for us is to raise awareness of the dangers of artificial light at night and we have already come a long way now that the American Medical Association (AMA) recently announced its new policy recognising adverse health effects of exposure to light at night and encouraging further research into the matter,” said Professor Abraham Haim, a leading authority on light pollution, who coordinated the 21st International Congress of Zoology (ICZ) that was held recently at the University of Haifa, Israel.

The participants were in full agreement that exposure to light at night affects circadian rhythms in nature - humans, animals and plants - which when thrown off can result in various illnesses and adverse symptoms. Prof Haim presented one of his studies showing the adverse effects of exposure to light at night (LAN) - particularly short wavelength blue LED - in blind mole rats and in seeing rats, both of which showed varying levels of damage to their metabolic rates, hormone production, body mass and oxygen consumption following exposure to LAN, as well as suppressed levels of melatonin production, which is responsible for tumour growth.

“We expect to find similar results of damage from human exposure to LED lighting,” Prof Abraham concluded. He pointed out that “Western youngsters were typically surrounded by this sort of lighting in the confines of their own bedroom; from the smartphone, computer screen and television.” Additionally, “Street lights in populated areas are responsible for 60% of LAN pollution, which is intensified under cloudy conditions when the light is reflected back down to the ground,” said Dr Franz Holker of the Leibniz Institute in Germany.

Also participating in the panel were James Hale of the University of Birmingham, UK and Dr Rachel Ben-Shlomo and L Ashkenazi of the University of Haifa.