Light pollution, its effects on environment and why we should be bothered

Light pollution is one of the most rapidly increasing type of environment degradation whose levels have been growing exponentially.

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Kolkata: The word pollution usually paints a picture filled with dirt, garbage and smoke or an imaginative mind may even think about honking cars to relate to noise pollution but how many of us think about light pollution? The answer may hover around ‘very few and some people’ but the effects of light pollution can be deep and if we do not collectively wake up to the issue, it may lead to further deterioration of the ecological balance.

Here’s a quick guide to light pollution.

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What is light pollution?

Light pollution is the presence of excessive, unwanted and inappropriate use of artificial outdoor light, especially at night time. Ecological light pollution includes chronic or periodic increase in illumination, unexpected changes in illumination and direct glare.

Light pollution is one of the most rapidly increasing type of environment degradation whose levels have been growing exponentially over the natural nocturnal lighting levels provided by the cosmic structures like sun and moon. The nighttime glow of artificial light not only cause series of problems for humans but also for wildlife and thus the environment at large.

light pollution
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Human beings being diurnal animals are attempting to expand the use of light at night as they try to extend activities into the usually dark hours. All the anthropogenic structures are lit at night with high levels of illumination. They include streets, roads, bridges, airports, commercial and industrial buildings, sport centers and homes. All are lit with high lighting levels with two or more objectives in mind. The shopping malls are heavily lit not only to attract costumers but also to create a lively environment, stimulating the shopping and spending vibes among them.

In a research carried out between 2004 and 2006, public areas were lit for the prevention of crime but the same showed no effect or in simple words, lighting could not reduce crime rates. The First World Atlas of the artificial night sky brightness by Cinzano, Falchi and Eldvidge in 2001 states that more than 60% of the world population lives under the light-polluted skies out of which 9% of them reside in the USA and the European countries.

Are light and air pollutions related?

According to studies by the National Oceanic and Atmospheric Administration and the cooperative institute for research in Environmental Sciences at the university of Colorado, excessive unwanted light can contribute to air pollution. Up light from outdoor lighting leads to sky glow over studies which interfere the chemical reactions taking place naturally to clean the air during night time hours.

Every night chemicals emitted from vehicles exhaust and other anthropogenic sources are broken down by a form of nitrogen oxide called the nitrate radical, thus preventing the formation of harmful ozone, smog and other irritants. This process of beneficial destruction occurs only in the hours of darkness as sunlight destroys the naturally-formed nitrate radical. Results of the measurements taken in Los Angeles by aircraft conclude that city lights slow down the nighttime cleansing process by 7% and increase ozone pollution up to 5%.

How does light pollution affect plants and animals?

Artificial lights attract specific organisms like moths, frogs and sea turtles, landing them in areas where they are not supposed to be, thus concentrating them as a food source to be preyed upon or simply resulting in a trap which exhausts and eventually kills them. It also at the same time repels some organisms thus leading to a loss in their habitat. Apart from this, light pollution alters the reproductive cycle and the sleep cycle of animals. While humans can prevent this by switching off the lights as per their requirements, animals on the contrary are bound to tolerate it.

Migratory birds get their visual pigments bleached by the artificial lights thus causing them to lose sight of the horizon and cycle within the cone of the light endlessly. They sometimes also die from exhaustion or collision with the light source.

Effect of light pollution on human beings

Human beings are dependent on natural body cycles called circadian rhythms and the production of melatonin which are regulated by light and darkness. On exposure to light while sleeping, the melatonin production gets suppressed as a result of which, they suffer from sleep disorders and other health-related problems like increased headaches, work fatigue, medically-defined stress and some forms of obesity due to lack of sleep and increased anxiety.

How to reduce light pollution?

The good news about light pollution is that it can be rapidly reduced and that too easily by shielding the lights properly. A simple practice of using the lights only at the required time and also in the required amount can reduce the pollution to great levels. The use of energy efficient bulbs and bulbs with appropriate spectral power distributions are the tasks at hand.

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Shristi works as a project coordinator but is a passionate author. She wields her pen on issues around public health, lifestyle and environment. A traveller too, Shristi can paint pictures with her words when it comes to travelogues.