Effects of Light Pollution

Why is the wrong kind of night-time light so bad?

It has unintended consequences in many areas, some of which might be surprising. For light pollution’s impact on any of the areas below, just follow the links (links to go live when the site is complete).

  • Health (according to the AMA Council on Science and Public Health 2012 report)
    • disruption of circadian rhythms
    • disruption of sleep
    • nighttime suppression of melatonin levels
    • increased risk of cancers and other diseases such as diabetes
  • Safety
    • disability glare
    • discomfort glare
  • The Natural World
  • Direct Costs

Light Pollution Harms the Environment

The effects of light pollution on animals in the environment are numerous and becoming better understood. Unfortunately, is is far, far easier to set up a badly installed light outside than it is to understand the negative effects  “down-light” from it. U.S. roadways contribute a huge amount of waste light. All of that bad lighting could be redone by replacing the up-pointing 300W halogen bulbs with more efficient LED lights and by pointing the LEDs down. This one small change would cost far less for the taxpayers without causing a single change in the quality of information delivered to the traveler or compromising their safety. (Though with white light LED lights, here too, caution must be used. These lights emit high levels of bluish light that interferes with our night vision.)

Bad lighting does not stop just at the roads. Tiffany Saleh wrote a good article on the “Effects of Artificial Lighting on Wildlife” in the WildlandsCPR.org web site.

This page covers some of the impacts that light pollution has on species which have lived on this planet far longer than us “johnny-come-lately” humans. In the span of a mere one hundred years, our creation of the never-occurring night is having some real effects on the animals that were here before us.

One reason these effects are felt by the animal world in addition to the human world is that many animal species use the same mechanism we do to regulate their daily lives: melatonin. Melatonin is the chronobiotic hormonal regulator of neoplastic cell growth, which means that it is the hormonal signal of our biological clock.” This hormone is used for similar functions in mammals worldwide. It is one of the oldest hormones know; it basically signals to genes whether it is light out or not. Thus, light pollution affects animals as well: not just mammals, though. It is even found in amphibians, as mentioned below.

But melatonin is more than just some ancient hormone buried deep within us and the animals that are impacted. Night tells so many animals when to eat, when to sleep, when to hunt, when to migrate or even when to reproduce. It is estimated that half of all life on earth starts daily activities at sundown. Here is a brief, incomplete accounting of how light pollution harms those living outside our materialistic world.


Astronomically, it decreases the signal-to-noise ratio. This means that, just like a fog, the artificial light washes out and obscures faint fuzzy nebulae, galaxies, and even the stars that should be seen in the night sky. This artificial fog of light noise blocks/hides the stars that are so necessary to astronomy. Light can be a pollutant, for any form of pollution is an undesirable change in the physical, chemical, or biological characteristics of the natural environment, created about by man’s activities. It may be interfering to nonhuman life. Pollution may affect the soil, rivers, seas, or the atmosphere. Thus, the resulting long term effects of light pollution is just as hazardous to us, as well as the environment, as a chemical spill would be all across our land. (However, unlike a one-time chemical spill, we go back and consume ever more energy resources just to recreate the same pollutant, night after night!) So light pollution is a true pollutant, for it alters the natural quantity of light in the night environment due to the introduction, incorrectly installed and used artificial lights.


We in South Florida should take this into account. As it is so warm down here in South Florida, we do a great deal of our activities after dark. Hence, field athletic activities often take place in the evening or even into the night hours. It is the lights of those fields that can be disrupting to others.

As an example, the following two images are of athletic fields near the observatory dome at FAU. The first field has its lights pointed outwards and is intensely discomforting, almost bordering on disability levels. Its glare trespasses in all directions and is debilitating to our astronomical studies. As a means of self-protection, eyes naturally adapt to the brightest objects in view. They do so by constricting the pupil’s opening (or optically they stop-down the eyes’ aperture). Because of this constriction, seeing faint objects around you or in the sky are much harder to do in the presence of the contrasting bright lights. In the observatory, we have to alter our schedule, and of course our students’ and visitors’ schedules, just to work around this light pollution, but we only get one night in the week to do so and yet a lot of students to teach, which seems extremely unfair as I can say that our observations would not be as disrupting to their athletic activities, as their activities are to our observations.

The light from the field is so bright that there is nothing in the sky that one can see above the field, with the exception of a little orange ball to the right of the picture’s middle. If you hover your mouse cursor over the image, you’ll be alerted to this little orange ball and find out it is the full moon, as taken on Sept. 13th, 2011. The field lights appear many times brighter than the moon. Then consider that our eyes see light logarithmically, which means that if the field lights appear that bright, then they are orders of magnitude brighter.

An overly lit atheletic field.

The next image is of a newer field which has its lights pointed downwards; its light beams demonstrate their direction. Even though there are many more lights, some poorly oriented nearby and others in the distance (I-95 and the airport), our eyes and the cameras are not so stopped down that one can even see some of the distant clouds in the picture. The glints of light that bounce off some of the field’s light shields are nowhere near as blazingly bright as the first field emits. Note that both fields are about equidistant from our dome, though they were taken on different nights.

A better designed atheletic field.

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