Light pollution

Light pollution

Light pollution

May 10, 2021
6 mins to read

Light pollution is a new source of environmental pollution after the pollution of exhaust gas, wastewater, waste residue and noise, mainly including white bright pollution, artificial daylight pollution and colored light pollution. Light pollution is threatening people's health.

In daily life, people's common condition of light pollution is mostly the dizziness of pedestrians and drivers caused by the reflection of mirrored buildings, as well as the discomfort caused by unreasonable light to human body at night.


What is light pollution

1. Excessive light radiation on human life and production environment caused by adverse effects of the phenomenon. Including visible light, infrared and ultraviolet radiation caused by pollution.

2. One of the factors that affect the limit of the faintest celestial objects that can be detected by optical telescopes. Usually refers to the effect of atmospheric glow over the observatory, zodiacal and galactic background light, urban night skylight, etc. to brighten the background of the stars.

The problem of light pollution was first raised in the 1930s by the international astronomical community, which considered light pollution to be the negative effect on astronomical observations caused by the brightening of the sky by outdoor lighting in cities. It was later called "interference light" in the United Kingdom and the United States, and "light pollution" in Japan.

How bad is light pollution

Harmful to human health, eyes damage

Myopia is related to the environment, and people know that water pollution, air pollution, and noise pollution are harmful to human health, but they are not aware of the potential threat around them - dry light pollution, which is seriously damaging people's eyes.

People are increasingly aware of the importance of the environment to human survival and health. People are concerned about water pollution, air pollution, noise pollution, etc., and take measures to rectify them, but not enough attention to dry light pollution. The consequence is that various eye diseases, especially myopia rate is rapidly rising. According to statistics, China's high school students myopia rate of more than 60%, ranking second in the world.

In the 1930s, scientific research found that the frequent flickering of fluorescent lights would force the pupil to zoom frequently, causing eye fatigue. If stimulated by bright light for a long time, it can lead to retinal edema and blurring, and in serious cases, it can destroy the light-sensitive cells on the retina and even make the vision suffer. "The stronger the light and the longer the time, the greater the irritation to the eyes." The glass curtain wall of a building is like a huge mirror, reflecting light into a high-speed car, which can cause sudden temporary blindness and visual illusion in people, and easily lead to traffic accidents.

For this reason, China invests a lot of money and manpower every year to deal with myopia, but the results are not very effective, the reason is not to improve the visual environment as a fundamental start. Health experts believe that the visual environment is the main cause of myopia, rather than eye habits.

According to the relevant experts, the visual environment in the dry light pollution can be divided into three kinds: one is the outdoor visual environment pollution, such as building facades; two is the indoor visual environment pollution, such as indoor decoration, indoor bad light color environment; three is the local visual environment pollution, such as books and paper, certain industrial products, etc..

With the development of urban construction and the progress of science and technology, daily life in the building and interior decoration using mirrors, tiles and white powder wall is increasing, close reading and writing using books and paper more and more smooth, people almost put themselves in a "strong light and weak color" of "artificial visual environment " in.

According to scientific determination: general white powder wall light reflection coefficient of 60% to 80%, mirror glass light reflection coefficient of 82% to 88%, especially smooth powder wall and white book paper light reflection coefficient of up to 90%, than grass, forest or hairy surface decorations about 10 times higher, this value greatly exceeds the human body can withstand the range of physiological adaptation, constitutes a new source of modern pollution. Research shows that dry light pollution can cause damage to the cornea and iris of the human eye, inhibit the function of retinal photoreceptor cells, causing visual fatigue and vision loss.

According to the relevant health departments of dozens of cabaret laser equipment investigation and measurement shows that the vast majority of cabaret laser radiation pressure has exceeded the limit value. This highly intensive thermal beam through the lens of the eye and then focused on the retina, the temperature of the spot can reach 70 degrees Celsius, which is very harmful to the eyes and brain nerves. It can not only cause damage to vision, but also cause headache, dizziness, cold sweat, neurasthenia, insomnia and other central nervous system disorders.

Causes cancer

According to a 2001 article in the Journal of the National Cancer Institute, a Seattle cancer research center surveyed 1,606 women and found that night shift women were 60% more likely to develop breast cancer; the longer the night shift, the more likely they were to develop the disease. Magazine confirmed this claim. Scientists surveyed 147 communities in Israel and found that the more light pollution there was, the more likely women were to develop breast cancer. The reason for this may be that unnatural light suppresses the body's immune system, affecting hormone production and disrupting the endocrine balance that leads to cancer.

Produces negative emotions

Light damage may cause headaches, fatigue, decreased sexual performance, increased stress and anxiety. Animal model studies have shown that when light is unavoidable, it can have a negative effect on mood and anxiety.

Recent studies by scientists have shown that colored light pollution not only impairs human physiological functions, but also has an effect on human psychology. The "spectral light chromaticity effect" measurement shows that if the psychological impact of white light is 100, the blue light is 152, purple light is 155, red light is 158, the highest ultraviolet light is 187. If people are under the long-term exposure to colored light, its psychological accumulation effect, but also to varying degrees will cause tiredness and weakness, dizziness, loss of libido, impotence, and anxiety. If people are exposed to colored light for a long time, the cumulative psychological effects can also cause varying degrees of tiredness, dizziness, loss of libido, impotence, menstrual disorders, neurasthenia and other physical and mental disorders.

The visual environment has seriously threatened the healthy life and work efficiency of human beings, causing a lot of losses to people every year. Therefore, it is urgent to pay attention to visual pollution and improve the visual environment.


Bring ecological problems

Light pollution affects the natural life pattern of animals, and the affected animals are not separated from day and night, making their activity ability problematic. In addition, their ability to identify location, competition, communication and psychology will be affected, and more importantly, the position of predators and prey will be adjusted to each other.

Some studies have pointed out that light pollution threatens the survival of plankton in the lake, such as daphnia, because light damage helps algae to reproduce and create red tide, which kills the plankton in the lake and pollutes the water.

Light pollution also disrupts the biological clock rhythm in plants, hindering their growth, causing their stems or leaves to discolor or even die; it affects the formation of plant flower buds, and affects plant dormancy and the formation of winter buds.

Light pollution can also affect the ecological balance in other ways. For example, artificial daylight can also harm insects and birds because bright light can disrupt the normal reproductive process of nocturnally active insects. At the same time, the high temperatures surrounding bright light can burn insects and birds to death. Lepidopterists and entomologists point out that bright light at night affects the ability of moths and other nocturnal insects to discern their direction. This makes it difficult for flowers that rely on nocturnal insects to spread pollen to reproduce because they are not assisted, which could result in the disappearance of certain species of plants from the planet and damage the entire ecosystem in the long run.

The effects of light pollution can also disorient migratory birds. The U.S. Fish and Wildlife Service estimates that four to five million or more birds die each year from the effects of light pollution. As a result, volunteers have set up the Deadly Light Project and are working with Toronto, Canada, and other cities to turn off unnecessary light sources during migratory bird migration to reduce mortality.

In addition, newly hatched sea turtles can also die from the effects of light pollution. This is because they are disoriented by light damage as they walk from the nest to the beach, and as a result, they are unable to reach a suitable living environment and die. Young seabirds are also affected by light pollution so that they are disoriented when they fly from their nests to the sea.

Night frogs and salamanders can also be affected by light pollution. Because they are nocturnal animals, they will be active when there is no light, but light pollution delays their activity time, making their activity and mating time shorter.

What is the main classification of light pollution

According to different classification principles, light pollution can be divided into different types. Internationally, the main light pollution is generally classified into 3 categories, namely, white light pollution, artificial daylight and colored light pollution.

White light pollution

When the sunlight is strong, the glass curtain wall of buildings in the city, glazed brick walls, polished marble and a variety of coatings and other decorative reflected light, bright white, dazzling. Expert research has found that people who work and live under white light pollution for long periods of time will suffer varying degrees of damage to their retinas and irises, with a sharp decline in vision and a cataract incidence of up to 45%. Also make people dizzy and upset, and even insomnia, decreased appetite, depressed mood, physical weakness and other symptoms similar to neurasthenia.

In summer, the strong reflected light from the glass curtain wall enters the nearby residential buildings, increasing the indoor temperature and affecting normal life. Some glass curtain walls are semi-circular; the convergence of reflected light is also likely to cause fire. Drivers driving under the hot sun will be unexpectedly hit by the sudden attack of the reflected light of the glass curtain wall, the eyes are strongly stimulated, it is easy to induce a car accident.

According to optical experts, mirrored building glass reflects light more strongly than sunlight, its reflectivity is as high as 82% to 90%, almost all the light is reflected, greatly exceeding the range of the human body can withstand. People who work and live under the white light pollution environment for a long time, easily lead to vision loss, dizziness, insomnia, palpitations, decreased appetite and depressed mood and other symptoms similar to neurasthenia, so that people's normal physiological and psychological changes, long-term will induce certain diseases. In summer, the strong reflected light of the glass curtain wall into the nearby residential buildings, destroying the original good indoor atmosphere, but also make the average room temperature rise 4 ℃ ~ 6 ℃. Affect normal life.

Mixed light

Different kinds of light sources mixed together will seriously affect passive receivers. And it may lead to car accidents. What's more terrible is that for pilots flying at night, they need to spend energy to find and identify the aviation signal lights among these various kinds of light.



Bright lights in the dark. High beams on a well-lit city street can cause pedestrians or drivers on the opposite side of the street to briefly "lose their vision" and cause accidents. And, when not properly protected, this glare can also harm one's eyesight. With the rapid growth of the number of cars, a technology that can greatly improve the brightness of driving lighting xenon lights are widely used in automotive lighting. However, this advanced lighting technology has repeatedly become the killer of road light pollution, causing hidden dangers to road safety. The current national standard GB4599-94 "automotive front lighting performance" has been abolished, GB 4599-2007 "automotive filament bulbs headlights" instead. Requires the vehicle "near-light, far-light brightness is not dazzling", but in practice, "not dazzling" the standard is difficult to grasp.

Artificial daylight

After nightfall, shopping malls, hotels on the advertising lights, neon lights flashing, dazzling. Some strong beams of light even straight into the sky, making the night as day, the so-called artificial day. In such a "city that never sleeps", light invasion caused by excessive light sources affects the daily rest of others, making it difficult to sleep at night, disrupting the normal biological clock of the human body, resulting in low efficiency during the day. The sky is too bright to see the stars, affecting astronomical observations, aviation, etc. Many observatories are forced to stop working as a result. According to astronomical statistics, at night when the sky is free from light pollution, about 7,000 stars can be seen, while in large cities where street lights, background lights, and landscape lights are shot indiscriminately, only about 20 to 60 stars can be seen.

Visual Pollution

It refers to the cluttered visual environment in the urban environment. For example, the city streets are cluttered with wires and telephone lines on sides, cluttered garbage waste, messy goods stalls and colorful advertising posters.

Colorful light pollution

The black lights, rotating lights, fluorescent lights and flashing colored light sources installed in dance halls and nightclubs constitute color light pollution. It is measured that the intensity of ultraviolet light produced by black lights is much higher than the ultraviolet light in the sun, and the harmful effects on the human body last for a long time. If people receive such exposure for a long time, it can induce nosebleeds, tooth loss, cataracts, and even lead to leukemia and other cancerous changes. Color light sources dazzle people, not only to the eyes, but also interfere with the central nervous system of the brain, making people feel dizzy, nausea and vomiting, insomnia and other symptoms. If people are under the long-term exposure to colored light, its psychological cumulative effect, but also to varying degrees will cause tiredness and weakness, dizziness, neurasthenia and other physical and mental disorders.

In addition, some scholars also according to the size of the impact of light pollution will be divided into "outdoor visual environment pollution", "indoor visual environment pollution" and "local visual environment pollution". Among them, outdoor visual environment pollution including building facades, outdoor lighting, etc.; indoor visual environment pollution including indoor decoration, indoor bad light color environment, etc.; local visual environment pollution including books and paper and certain industrial products, etc..

In short, light pollution can lead to energy waste, and damage to human physiological and psychological health. In addition, excessive light pollution can seriously damage the ecological environment, and will also have a negative impact on traffic safety, aerospace science research. Before the government makes effective adjustments to light sources, we must be careful to stay away from similar sources of pollution.

Professor Ma Jian of Tianjin University in China, the occurrence of light pollution and the impact of time as a classification standard, light pollution is divided into "day light pollution" and "night light pollution", the former white light pollution that belongs to the day light pollution, artificial daylight and color light pollution belongs to Night light pollution.