What is the Origin of Environmental Light Pollution?

The concept emerged in the fields of astronomy and ecology but has been adopted by chronobiology and public health as an environmental determinant of health. It is a direct consequence of urbanization and widespread electric lighting, which have fundamentally altered the natural light-dark cycle to which human physiology is adapted. Clinical understanding links this exposure to modern health epidemics.

What is the Mechanism of Environmental Light Pollution?

Environmental light pollution operates by inappropriately stimulating the intrinsically photosensitive retinal ganglion cells (ipRGCs) in the retina, even at low lux levels. This light signal is transmitted to the suprachiasmatic nucleus (SCN), which interprets it as daytime, leading to the suppression of melatonin production by the pineal gland. The resultant chronic melatonin deficiency and circadian phase delay impair nocturnal repair processes and elevate the risk for hormone-sensitive conditions.

Environmental Light Pollution ∞ Area

Environmental Light Pollution

Meaning

The pervasive and excessive introduction of artificial light into the nocturnal environment, resulting in chronic exposure to non-natural light intensities and spectra during biological night. This external stressor is clinically significant because it compromises the fundamental dark-signal required for neuroendocrine processes, notably the synthesis and secretion of melatonin. It is recognized as a significant, yet often overlooked, disruptor of human chronobiology and hormonal health.