What is light pollution?
Light pollution is the inappropriate use of artificial light at night.
“Light pollution is an environmental pollutant that harms our planet and robs us of the opportunity to experience the wonder of a natural night sky.” (IDA, 2020)
Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. Much outdoor lighting used at night is inefficient, overly bright, poorly targeted, improperly shielded, and, in many cases, completely unnecessary. This light, and the electricity used to create it, is being wasted by spilling it into the sky, rather than focusing it on to the actual objects and areas that people want illuminated.
The inappropriate or excessive use of artificial light – known as light pollution – can have serious environmental consequences for humans, wildlife, and our climate.
Components of light pollution include:
Clutter is the bright, confusing and excessive groupings of light sources, such as many lit advertisements signs in one place.
Light trespass is light falling where it is not intended or needed. Light trespass can be spill light from a streetlight or floodlight that enters a window and illuminates an indoor area causing problems, like sleep deprivation.
Skyglow is the brightening of the night sky over inhabited areas, which reduces the contrast of stars or other celestial objects against the dark sky background. Some stars will blend into the background and become indistinguishable.