The National Committee for the Examination and Approval of Scientific and Technical Terminology approves and publishes the definition of light pollution;
1, the phenomenon that excessive optical radiation has adverse effects on human life and production environment. Including pollution caused by visible light, infrared light and violet light.
2. One of the factors that affect the limit of the darkest celestial body that can be detected by optical telescope. Usually refers to the atmospheric glow over the Observatory, the background light of zodiacal light and the Milky Way, nightglow City and other effects that brighten the starry sky background.
The problem of light pollution was first put forward by the international astronomical community in the 1930s. They believe that light pollution is the negative influence of bright sky caused by urban outdoor lighting on astronomical observation. Later, Britain and the United States and other countries called it "interference light", while Japan called it "light damage".
Light pollution generally refers to all kinds of light that affects the natural environment, adversely affects human normal life, work, rest and entertainment, damages people's ability to observe objects, causes human discomfort and harms human health. People's eyes can adapt to a certain range of light radiation due to the adjustment of pupils, but when the light radiation increases to a certain amount, it will have a negative impact on human health, which is called "light pollution". Optical radiation with wavelength from 10 nm to 1 mm, namely ultraviolet radiation, visible light and infrared radiation, may become the source of light pollution under different conditions.
Harm of light pollution:
1, make the night sky pale
In 2009, Australian Cosmos magazine reported that according to a recent survey in the United States, 70% of the world's population lives in light pollution, and the light pollution caused by China lanterns at night has prevented 20% of the world's people from seeing the beauty of the Milky Way with naked eyes. Elvige, one of the authors of the survey report, said: "Many people lost the night sky, and it was our lights that made the night sky pale." . He thinks that about two-thirds of the people in the world live in light pollution now. In the night sky far away from the city, you can see more than 2000 stars, while in big cities, you can only see dozens.
In Europe, America and Japan, light pollution has long attracted people's attention. The United States has also established the International Dark Night Sky Association to combat light pollution.
Affect human health
2. Damage to eyes
Myopia is related to the environment. People all know the harm of water pollution, air pollution and noise pollution to human health, but they don't realize the potential threat around them-dry light pollution is seriously damaging people's eyes.
In recent years, with the increasingly serious environmental pollution and countless tragedies, people are increasingly aware of the importance of the environment to human survival and health. People pay attention to water pollution, air pollution, noise pollution and so on, and take measures to rectify them vigorously, but not enough attention to noise pollution. As a result, the incidence of various eye diseases, especially myopia, has risen rapidly. According to statistics, the myopia rate of senior high school students in China exceeds 60%, ranking second in the world.
In 1930s, scientific research found that frequent flashing of fluorescent lamps would force pupils to zoom frequently, causing eye fatigue. If stimulated by strong light for a long time, it will lead to edema and blurring of the retina, which will seriously destroy the photoreceptor cells on the retina and even affect vision. "The stronger the light, the longer the time, and the greater the irritation to the eyes." The glass curtain wall of the building is like a huge mirror. When the reflected light enters a high-speed car, it will cause sudden temporary blindness and optical illusion, which will easily lead to traffic accidents.
To this end, China spends a lot of money and manpower to deal with myopia every year, but the effect is not great, because it does not start from improving the visual environment. Relevant health experts believe that the main cause of myopia is the visual environment, not the habit of using eyes.
According to experts, dry light pollution in the visual environment can be roughly divided into three types: one is outdoor visual environment pollution, such as building exterior walls; Second, indoor visual environment pollution, such as indoor decoration, indoor bad light and color environment. Third, local environmental pollution, such as books, paper and some industrial products.
With the development of urban construction and the progress of science and technology, mirrors, tiles and whitewashed walls are increasingly used in daily life for architecture and interior decoration. Books and papers used for close reading and writing are becoming more and more fluent, and people almost put themselves in an "artificial visual environment" with "strong light and weak color".
At present, few people realize the harm of dry light pollution. According to scientific determination, the reflective coefficient of commonly painted walls is 69-80%, and that of mirror glass is 82-88%. The light reflection coefficient of particularly smooth whitewashed walls and white writing paper is as high as 90%, which is about 10 times higher than that of lawns, forests or rough decorative surfaces. This value greatly exceeds the physiological adaptation range that the human body can bear, and constitutes a new modern pollution source. Studies have shown that dry light pollution can damage the cornea and iris of human eyes, inhibit the function of retinal photoreceptor cells, and cause visual fatigue and vision decline.
According to the investigation and measurement of laser equipment in dozens of dance halls by relevant health departments, the laser radiation pressure in most dance halls has exceeded the limit. When this high-density thermal beam passes through the lens of the eye and focuses on the retina, the temperature of the focusing point can reach 70 degrees Celsius, which is very harmful to the eyes and brain nerves. It will not only damage people's eyesight, but also cause brain central nervous system diseases such as headache, dizziness, cold sweat, neurasthenia and insomnia.
4. Induce cancer
Many studies have pointed out that night shift work is related to the increased incidence of breast cancer and prostate cancer. In 200 1 year, the Journal of the National Cancer Institute published an article saying that a cancer research center in Seattle surveyed 1606 women and found that the probability of breast cancer among night shift women was 60% higher than that of ordinary people. The longer you work the night shift, the more likely you are to get sick. In 2008, a report in the journal International Biological Clock confirmed this statement. After investigating 47 communities in Israel/Kloc-0, scientists found that the more serious the light pollution, the more likely women are to get breast cancer. The reason may be that non-natural light inhibits human immune system, affects hormone production, destroys endocrine balance and leads to cancer.
5. Have a bad mood
Mild injury may lead to headache, fatigue, decreased sexual ability, increased stress and anxiety. Animal model studies have proved that when light is inevitable, it will have adverse effects and anxiety.
The latest research by scientists shows that colored light pollution not only damages people's physiological functions, but also affects people's psychology. The measurement of "spectral chromaticity effect" shows that if white
The psychological influence of colored light is 100, blue light is 152, purple light is 155, red light is 158, and the highest ultraviolet light is 187. If people are exposed to colored lights for a long time, their psychological accumulation effect,
It can also cause physical and mental diseases such as fatigue, dizziness, loss of libido, impotence, irregular menstruation and neurasthenia to varying degrees.
The visual environment has seriously threatened people's healthy life and work efficiency, causing a lot of losses to people every year. Therefore, it is urgent to pay attention to visual pollution and improve the visual environment.
6. Ecological problems
Light pollution has affected the natural life law of animals, and the affected animals stay around the clock, which makes their mobility problems. In addition, its position discrimination ability, competitiveness, communication ability and psychology will be affected, and more importantly, the position modulation between predators and prey will also be affected.
Some studies have pointed out that light pollution threatens the survival of plankton in the lake, such as water fleas, because light damage will help algae reproduce and produce red tides, thus killing plankton in the lake and polluting water quality.
Light pollution can also destroy the biological clock rhythm in plants, hinder their growth, lead to discoloration of their stems or leaves, and even death; It will affect the formation of flower buds, dormancy and winter buds.
Light pollution can also affect the ecological balance in other ways. For example, artificial sunlight can also harm insects and birds, because strong light will destroy the normal reproduction process of nocturnal insects. At the same time, insects and birds will be burned to death by the high temperature around strong light. Scale-winged scholars and entomologists point out that the bright light at night will affect the ability of moths and other nocturnal insects to distinguish directions. This makes it difficult for flowers that rely on nocturnal insects to spread pollen to reproduce without assistance. As a result, in the long run, some kinds of plants may disappear from the earth and destroy the whole ecological environment.
Migratory birds will also get lost because of the influence of light pollution. According to the data of the U.S. Department of Fish and Wildlife, the number of birds killed by light pollution reaches 4 million to 5 million every year, or even more. Therefore, volunteers set up a plan to pay attention to deadly light, and cooperated with Toronto and other cities in Canada to turn off unnecessary light sources as much as possible during migratory birds' migration to reduce their mortality.
In addition, newly hatched turtles will also die due to the influence of light pollution. This is because they were damaged by light when they walked from the nest to the beach, and they lost their sense of direction. As a result, they died because they could not reach a suitable living environment. Young seabirds are also affected by light pollution, which makes them lose their way when flying from their nests to the sea.
Night frogs and salamanders are also affected by light pollution. Because they are Nocturnal Animals, they move when there is no light. But light damage will delay their activity time and shorten their activity and mating time.