ILA 2015 - Prof. Abraham Haim - When Does Light Become A Source of Pollution?

Presentation given by Prof. Abraham Haim at the International Light Association 2015 Conference, in Tallinn, Estonia.

When Does Light Become A Source of Pollution?

Light the source of energy for our planet is accepted by western and other societies as a blessing, given to us as a present. No doubt that light has its advantages and humans as diurnal creatures we worship light and looked for ways of extending the photo-phase. Light apart of an energy source is also an important signal for the activity of various systems and under natural conditions it cycles with scoto-phase, the relatively dark period of a 24h cycle. The illumination of our planet changes not only on a daily basis but also in annual cycles, the changes are in levels of intensity and wavelength to which organisms became adapted throughout the period of organismal-evolution. Light-therapy is given to patients at different hours of the day, so if light at a certain wavelength and intensity is a signal within a daily or an annual cycle, is it a factor we should consider during our light treatment?

Illumination technologies are also changing and since the second half of the twentieth century illumination producers are moving from the classical incandesced bulbs to short wavelength illumination at night, illumination technologies considered as more efficient and more environmentally friendly. Short wavelength (460-530nm) illumination is used during the early morning hours, as an excellent efficient treatment for seasonal affective disorder (SAD). The reason for its efficiency is the suppression pineal melatonin production. Therefore, we should ask if such an illumination source is a good idea for treatment at night time. Humans in modern times worship technologies without asking too much about health consequences of exposure to new technologies involving illumination so the latest technology – the LED light-emitting diode is invading our lives, is it correct to use this type of illumination? If we use this illumination how should we be protected against its negative effects on our health?