1. Definition:
We talk about light pollution when artificial lighting is so numerous and omnipresent that it damages the normal and desirable darkness of the night.
Thus, at nightfall, countless sources of artificial lights (urban lighting, advertising signs, shop windows, offices lit permanently ...) take over the sun in urban centers to the smallest village .
Light pollution is a form of pollution relatively little mentioned because a priori little harmful to health when compared to more conventional pollution, but it is not without consequences on the living and can easily be reduced.
2. Possible causes:
Light pollution is the consequence of the diffusion of artificial light by drops of water, dust particles and aerosols suspended in the atmosphere.
The importance of this pollution is directly related to several factors. Air pollution is an aggravating factor of the phenomenon as well as:
- The use of poor lighting systems. Many devices do not focus the light on the area to be illuminated, others do not properly fold the radiation to the ground. This results in a direct loss of energy, the deplorable performance of which also results in poor lighting quality, causing the users to be dazzled.
- The overpowering of the facilities, it can be either too many points
light on a given sector, the exaggerated power installed on the device.
These situations are frequent and occur for various reasons: commercial arguments, feeling of security, search for aesthetics ...
- A longer operating time than the real needs. Depending on the location or site, the lighting duration should be adapted to the real needs.
3. The possible consequences for health:
In humans, light pollution is suspected of disrupting the biological clock, altering the hormonal system, which requires 5 to 6 hours of darkness to function properly, and the secretion of melatonin, hormone that affects sleep , reproduction, aging ...
In addition, according to some researchers, producing less melatonin can be an aggravating factor of cancer. For example, women who work at night would have a significantly higher risk of breast cancer. Other studies have shown a less significant occurrence of breast cancer among the blind.
More research on the effects of artificial light on human health is under way
