Artificial light at night as a health risk factor - Can the effect of different illumination sources be measured?

No doubt that Artificial Light at Night (ALAN) has brought economic prosperity to humans and prolonged nighttime socialization up to "24/7 non-stop cities". The increasing illumination world-wide results in increased electricity production on the one hand but also an increase in light pollution on the other. As far as the classical incandescent bulbs are concerned, most of their electrical energy is emitted as heat and thus CO2 production is expected to increase following the increased electrical demands for air conditioning particularly in closed spaces. The solution in regards to ALAN was moving to short wavelength (SWL) illumination, where Light Emitting Diodes (LEDs) are considered the ultimate "energy efficient" technology available today. However, the concerns we want to raise are related to the negative impacts of the LED technology on both the environment and human health. On June 2012 the American Medical Association (AMA) passed a resolution that ALAN is a source of pollution as among others, it suppresses production of the pineal hormone melatonin, which is typically produced under dark conditions. In order to assess the sensitivity of melatonin suppression under variant illumination sources we developed an animal model for estimating the association between melatonin suppression, epigenetic modifications and breast cancer development. Our results reveal significant differences between the tested illumination types.