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Light pollution is basically the disruption of unnecessary natural ambient lighting at night. The most used legislative definition qualifies it as any radiation of direct light outside the areas to which it is functionally dedicated, and in particular towards the celestial vault.
This alteration causes damage of various kinds: environmental, scientific, cultural and economic. Every year a day of reflection is celebrated on this theme, which has become a very important global problem. Light pollution leads directly to further environmental chemical pollution due to excess energy production, also partly increasing unnecessary global warming.
Light pollution is the problems it presents
The Light pollution study, published in the La Revue du pratien, explained: "Artificial light can be a polluting agent deleterious for the retina, in relation to the toxicity of the blue band (380-500 nm) of the visible spectrum (380-700nm) specifically used in light-emitting diodes.
Photo- toxicity results from photochemical damage to the pigmented epithelium and retinal photoreceptors responsible for the visual function of the retina. Their photosensitive pigments, opsins for the cones and rhodopsin for the sticks, are consumed during the day and regenerated at night.Exposure to light at night seriously disrupts their metabolism.Photo-toxicity, along with heredity, is a major factor in degenerative diseases of the retina with, in addition to, the impact of age and tobacco for the most common of them, age-related macular degeneration: ARMD.
Exposure to artificial light at night (LAN) has a deleterious effect on the internal clock.Intrinsically photosensitive ganglion cells (ipRGSs) are responsible for the non-visual functions of the retina, and perceive ve the light signal that is transmitted to the internal clock to reach the pineal gland.
Light inhibits the secretion of melatonin and is able to advance or delay the clock depending on the time of exposure, causing desynchronization. Shift and night workers, like teenagers, are exposed to LAN. The incidence of breast cancer, higher in nurses exposed to LAN, is related to melatonin inhibition, sleep deprivation and desynchronization.
The exposure of adolescents to screens is also questionable because the LEDs of the devices emit a blue light, the impact of which on the clock is considerable. The chronic desynchronizations of both shiftworkers and adolescents should be considered a major public health concern."