The issue of the light pollution is gaining an increasing attention from public opinion. As a consequence, more and more researchers are investigating the undesired effects of the lighting under several point of views. One aspect is the increase of the the natural nocturnal lighting levels provided by stars and moon. In order to limit the problem researchers look for the more effective way of shielding lighting and prevent dispersion of light in upward directions. An other aspect are the effects of light radiation on human health when it hits skin and eyes. An interesting article has been published in Journal of Environmental Management available online since July 2011. Fabio Falchia, Pierantonio Cinzano (Istituto di Scienza e Tecnologia dell’Inquinamento Luminoso), Christopher D. Elvidge (NOAA National Geophysical Data Center), David M. Keith (Marshall Design Inc.) and Abraham Haim (The Israeli Center for Interdisciplinary Studies in Chronobiology) found that some kinds of the new LED lamps can reduce melatonin production also five times more than sodium lamps.
It has been proved that a decrease of melatonin levels can increase the incidence probability of some skin’s cancers.
Just to gain a clearer vision of the results of the research, let us consider the spectrum of the color temperature from lamps. While light from lamps with a color temperature below 5000 K is shifted in the orange range (warm colors), light with a color temperature above 5000 K is in the blue range (cold colors). It has been found that lamps emitting radiation above 5000 K, decrease more effectively melatonin levels.
Especially if the results of the research will be confirmed, public opinion should be awaken about this issue and moved towards safer LED lamps.
In conclusion, LED lamps by warm colors are better.
The original article by Fabio Falchia, Pierantonio Cinzano, Christopher D. Elvidge, David M. Keith and Abraham Haim can be found here
Italian society sensitive to the light pollution issue: http://cielobuio.org/