Light Pollution

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Light Pollution

Light pollution refers to the excess of man-made light which is commonly found in metropolitan areas and around cities. Prior to the invention of electric lights, man-made light pollution referred to artificial light generated by burning wood and oil. Usually, this type of light would only locally affect wildlife and temporarily obscure the night view for humans. Once electric lighting became widespread, this started to impact both the human view of the night sky as well as have ecological implications which prevent wildlife, such as birds and insects, from exhibiting their normal behavioral patterns.

Consider these light pollution facts:

  • 18.7% of the surface of the earth is considered to suffer from astronomical light pollution.
  • Only 40% of Americans live where it is dark enough for the human eye to adapt to night vision.
  • More pollution facts and their sources.
  • light pollution
    Light pollution in Salt Lake City.Image by makelessnoise

    The causes of light pollution are:

    • Lights

    This one is pretty obvious. Light pollution is caused by city lights and large metropolitan cities show a lot of light pollution. Light pollution is also caused on a smaller scale by street lights shining into homes. Many lights today have really broad ranges and will light up areas which are way outside thе necessary range.

    Why is light pollution bad?

    Light pollution is a problem largely because it is unpleasant for people and ruins their standards of living. Research suggests that light pollution negatively affects the sleeping patterns of humans. Astronomers have also had a problem with excessive lighting for a long time because it interferes with their observatories.

    Another problem with light pollution is how it prevents many animals, birds, and insects from exhibiting normal behavioral patterns, which poses a risk for certain species. It can negatively impact their foraging, reproduction, and communication.

    Ways to combat light pollution

    Light pollution is actually quite easy to fix on the individual level, but it is much more challenging at a large scale. For individuals, there are several ways to combat light pollution:

  • Turn off some/all of your lights
  • Really obvious but, it helps you sleep at night, lowers your electrical bills, and helps prevent disturbances to wildlife. Consider also that you may be paying for outdoor lightning all the way out on the street if it is hooked up to your electrical grid.

  • Install low intensity or automatic lighting
  • A lot of the bulbs you are using may easily be replaced by bulbs which don’t glow as brightly and save energy. Once again this saves electrical power and makes it easier on your eyes. You can even install automatic bulbs which only turn on when a motion sensor activates them. Don’t just buy the first bulb you find, only get a bulb that is as bright as you need when you need it.

    Unfortunately it is quite challenging to fix light pollution on the larger scale and this requires governments and companies to work together to install low-intensity lighting or to limit street lamps in certain area where they cause a lot of disruption to wildlife.


    Cinzano, P., Falchi, F. and Elvidge, C.D., 2001. The first world atlas of the artificial night sky brightness. Monthly Notices of the Royal Astronomical Society, 328(3), pp.689-707.

    Longcore, T. and Rich, C., 2004. Ecological light pollution. Frontiers in Ecology and the Environment, 2(4), pp.191-198.