And it is a known fact that suppressing the production of melatonin causes behaviour disruptions and health problems.
In this study, conducted by astronomers, physicists and biologists from ISTIL- Light Pollution Science and Technology Institute in Italy, the National Geophysical Data Centre in Boulder, Colorado, and the University of Haifa, researchers for the first time examined the differences in melatonin suppression in a various types of light bulbs, primarily those used for outdoor illumination, such as streetlights, road lighting, mall lighting and the like.
They found that the metal halide bulb, which gives off a white light and is used for stadium lighting, among other uses, suppresses melatonin at a rate more than 3 times greater than the high-pressure sodium HPS bulb that gives off orange-yellow light.
Also the light-emitting diode (LED) bulb, which also gives off a white light, was found suppressing melatonin at a rate more than 5 times higher than the HPS bulb.
"The current migration from the now widely used sodium lamps to white lamps will increase melatonin suppression in humans and animals," the researchers said.
Prof. Abraham Haim, head of the Centre for Interdisciplinary Chronobiological Research at the University of Haifa and the Israeli partner in the research concluded, "Just as there are regulations and standards for 'classic' pollutants, there should also be regulations and rules for pollution stemming from artificial light at night."
The study was recently published in the Journal of Environmental Management.