Causes, Effects and Solutions of Light Pollution

I’m a student working on an awareness project about light pollution. I live in a city and became interested in the problem of light pollution after the experience of traveling to a national park far from a city, and seeing the true night sky for the first time. I have since learned more about light pollution, and the effects is has on our environment. Through a series of articles, I am hoping to initiate discussion and raise awareness of this seldom mentioned form of human caused pollution.

What is Light Pollution

Light Pollution: (noun) brightening of the night sky caused by street lights and other man-made sources, which has a disruptive effect on natural cycles and inhibits the observation of stars and planets.

Like many types of pollution, light pollution is caused by humans. Unlike other forms of pollution however, light pollution is very easy to fix. With air pollution, it would take a very long time to clear out all the effects of smog and gas that we have put in the air. The same goes for water pollution and land pollution. There is one very simple way to fix light pollution: turn off the lights.

Light is one of the fastest things in the universe and if you cut off it’s source, say a lamp, things get dark quite quickly. Of course we can’t just turn off all of our lights - we need them for so many things, like headlights for our cars and lighting in our houses. Although it would be easy to end light pollution, humans in modern society more or less depend on artificial light.

Causes of Light Pollution

Many things cause light pollution. Just about anything that produces light can cause light pollution. Here are some examples:

  • Light coming out of our houses at night, like lamps
  • Garage lamps (this is a particular problem for me, as my neighbor has a very bright one that shines through my window at night).
  • Large downtown areas with skyscrapers that emit an enormous amount of light.
  • Cars, particularly the headlights. Busy roadways at night can create a lot of light.
  • Smog, and clouds cause the sky to appear a lot brighter than normal because they reflect light given off by cities.
  • Street lamps: Those without proper covering cause lots of unnecessary light to flood the sky.

The list goes on, but as you can see, even the most simple of things cause light pollution. A few people carelessly leaving on their lights is not the main cause of the problem. The problem is when there are thousands of cars and thousands of lamps, it lights up the sky at night.


Since I have talked about a few of the causes of light pollution, I would like to touch on some of the effects. Even if the culprit is just light, a form of energy, it still causes plenty of damage. Light pollution has a wide variety of negative effects on humans, as well as wildlife.

Animals and the environment

For as long as there has been life on Earth, living organisms have depended on the continuous cycle of night and day. Nocturnal animals, who only active at night, depend on this cycle to know when to come out. Same goes for non-nocturnal animals who sleep when the sun goes down. Now, with the introduction of light pollution, many animals can’t even tell the difference between night and day. Frogs, whose nighttime croaks you sometimes hear, are effected since the croaking is actually part of their mating rituals and frog populations in large cities with lots of light are decreasing.

Baby turtles, are also effected. When the turtles are born, they rely on the light from the horizon of the ocean to find their way to their new underwater home, but now they are attracted by the bright lights of cities and hundreds of thousands of baby turtles die this way every year. (I will write another article about this)

Migrating birds are also victims to humans creating absurd amounts of light. Birds use natural light sources (sun, stars, and moon) to find their way when migrating. However, with human creations, like lighthouses, birds get drawn away from their normal paths. One example of this would be the two light beams that are lit every September 11. I fully understand what those light beams represent, the two World Trade Centers that were victim to a terrorist attack, but I would like to point out the effect it has on migrating birds. Around 1.1 million birds have been caught by these lights between the years of 2008 to 2016. Birds get caught in the beams of light and they just fly around in circles until the sun comes up, or until NYC workers turn the lights off for a short period of time to let the birds fly away. This example is only relevant once a year, but what about lighthouses which have bright beams of light every night. Birds will fly around in these beams until they drop from exhaustion or run into buildings almost every night.

Effects on human health

Humans, as well have evolved with the steady rhythm of day and night. Everybody has a biological clock, also known as the circadian rhythm. This rhythm basically switches the cycles between being awake and being sleepy or drowsy. In response to this rhythm, out bodies create a hormone called melatonin. This hormone can control the cycles of sleep and being awake. Artificial light can interrupt the circadian rhythm and therefore result in less production of melatonin. This can cause problems in the functioning of the thyroid, pancreas, ovaries and many other parts of the body.

Blue Light is a type of light produced by LED lights, computer screens, TV screen and phone screens. This kind of light can penetrate all the way to the retina and can damage cells there which can lead eye damage and even permanent blindness.


What are some practical ways that we can reduce light pollution? In fact, there are many solutions and it doesn’t have to cost a fortune or leave us in the dark. As suggested by the International Dark-Sky Association(IDA) lighting should be only on when needed, only be lighting the area needed, be no brighter than necessary, minimize blue light putout, and be fully shielded (pointing down).

It is important to get outdoor lighting that is properly shielded. A lot of the light produced by outdoor lights is completely useless because it just goes up in the sky. It is not hard to find light covers, and the IDA has certified Dark Sky Friendly Lighting on its website.

Also, probably the most easy way to reduce the amount of light that you produce is to just turn off the lights. Security lights should be activated by motion sensors instead of being left on all night. Do you really need to leave your holiday lights on all night? These are simple measures that everyone can take to reduce light pollution.


Thank you so much for reading this and I hope that you learned something. I am doing this for a school awareness project and would welcome your comments and feedback.