Turn off the light every time you can, experts advise

Light pollution is one of the easiest forms of pollution to remove.

(Source: Gabriel Kuchta, SME)

A glossary of words as well as exercise related to this article are also published online.

When we look up at the night sky and cannot see the stars, it is not always due to cloudy weather. Too much light from streetlights or buildings may be the reason the stars are dim.

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Experts call this phenomenon light pollution. With excessive artificial lighting, not only is the work of astrophysicists harder, but it can even affect the natural processes of the human body. When there is too much light from the street in the bedroom at night, for example, it may cause a disorder in the production of hormones.

“Hormones, as for example melatonin, manage the inner clock, the so called biorhythm,” explains Martin Labuda from the Faculty of Natural Science at Comenius University.

A four-year international study, in which Comenius University in Bratislava participated, has shown that chronically breaking circadian rhythms can lower the quality of sleep and cause problems with metabolism and immunity, and could eventually lead to serious diseases, such as obesity, diabetes, or depression. Altogether 18 countries, including Slovakia, were involved in the project LoNNe (Loss of the Night Network).

Humans are not the only ones to suffer due to artificial lighting; the ecosystem could be hurt as well.

“For insects, lighting works as a trap: the insect revolves around the light, gets exhausted, and dies of hunger,” Labuda explained. On the other hand, the concentration of insects in one place could serve as an easy dinner for predators, such as bats or birds, he added.

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The origin of light pollution

Even a small lamp on your desk may become a source of light pollution if its light is ill-directed. When lighting a desk, we cast light on the keyboard or something on the top of the desk, but not the walls or ceiling. Every lamp should work in the same way, Labuda explained.

“Street lightning is often badly constructed; in the past ball-shaped lamps were often used,” said Jaroslav Merc, a member of the sector for protection against light pollution of the Slovak Academy of Sciences and the Slovak Union of Astronomers.

“These lamps would shine in all directions, not only downward as they should,” Merc continued. The purpose of street lamps is to provide light on roads or sidewalks, not up to the sky, he added.

Street lighting is not the only case of bad construction. Lights illuminating sights or billboards are often pointed upwards from the bottom, thus exceeding the space needing to be lit. Rome and London, for example, turn off illumination of sights at night, Merc explains.

What to do

Experts agree that one of the most important things is to direct light. A lamp should emit light at obtuse angles down to the ground. Also, lamps should be shaded by flat glass to direct light only to the place where it is necessary. Street lighting sensors or buttons to turn it on are also helpful. It would work similar to traffic lights – when a pedestrian walks around, only the necessary lamps would turn on, Labuda explained.

“Recently, many towns have been changing street lighting to LED lighting. Even though they lower the cost of electricity with this step, they often decide to have the lighting turned on for the whole night,” stated Labuda.

Turning off lights where we do not need them is definitely the right direction, he added. Some countries, like Italy, Slovenia, Germany or Switzerland, have already accepted regulations on lowering light pollution, whether at a local or national level, Merc mentioned.

“When applying for a building permit, it is also necessary to submit the lighting system project,” explained Labuda, adding that the rules for lighting projects are strict and the building permit will not be given if the rules are not adhered to.

Dark-sky places

Dark-sky places are areas with low light pollution which are under protection to keep the sky dark, divided into five different categories. The first such European park appeared in 2009 in Hungary, the Zselic Landscape Protection Area. Canadian national park Mont-Mégantic was the first internationally protected dark-sky area in 2007.

In Slovakia, there are several dark parks; the darkest sky is in National Park Poloniny. However, these parks are not certified international dark-sky parks.

“When there are international dark-sky parks, the surrounding towns also have to adopt rules to protect the park,” said Labuda, explaining the difference of a certified dark-sky park.

Is it going to be worse?

Experts do not want to turn off all the lights indefinitely, but better control over lighting could change the level of light pollution.

“Light pollution is one of the best removable pollutions,” said Merc. Labuda agrees, however, he is more pessimistic and, while he believes it would be possible to lower light pollution, it would be necessary for big metropolises to join in the efforts.

“In the future, light pollution will probably grow bigger, because with the developing economy of some Asian and African countries, there will be even more light,” he reasoned.

The Spectator College is a programme designed to support the study and teaching of English in Slovakia, as well as to inspire interest in important public issues among young people. The project was created by The Slovak Spectator in cooperation with their exclusive partner – the Leaf Academy.

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