Light pollution

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Light contamination , also known as photopollution , is the presence of anthropogenic light in the night environment. This is exacerbated by the excessive use of light, misdirected or obtrusive, but even the light used cautiously alters the natural state in a fundamental way. As a major side effect of urbanization, it is blamed for endangering health, disrupting ecosystems and damaging the aesthetic environment.

Video Light pollution

Definition

Light pollution is the addition/addition of the light itself, in analogies with sound, carbon dioxide, etc. The adverse consequences are many; some of them may not be known. The scientific definition thus includes the following:

• Degradation of photographic habitat by artificial light.
• Changes in natural light levels in the external environment due to artificial light sources.
• Changes in light levels in the outer environment (from those present naturally) due to man-made light sources. Indoor light pollution is the change in light levels in the indoor environment due to light sources, which harm human health.
• Introduction by humans, directly or indirectly, from artificial light to the environment.

The first three of the four scientific definitions above describe the state of the environment. The fourth (and the latest) describes the process of pollution by light.

Light pollution competes with starlight in the night sky for urban dwellers, disrupts astronomical observatories, and, like other forms of pollution, disrupts ecosystems and has adverse health effects.

Light pollution is a side effect of industrial civilization. The sources include the construction of exterior and interior lighting, advertising, outdoor lighting (eg car parks/parking lots), offices, factories, street lights and sports venues. This is most severe in densely populated, densely populated areas of North America, Europe and Japan and in large cities in the Middle East and North Africa such as Tehran and Cairo, but even a relatively small amount of light can be noticed and induced problem. Awareness of the effects of damaging light pollution began in the early 20th century (see for example Beston), but efforts to overcome the effects did not begin until the 1950s. In the 1980s the global dark-sky movement emerged with the founding of the International Dark-Sky Association (IDA). There are now educational and advocacy organizations in many countries around the world.

Maps Light pollution

Impact on energy usage

The proponents of energy conservation argue that light pollution must be overcome by changing people's habits, so lighting is used more efficiently, with less waste and less unwanted or unnecessary illumination creation. Some industry groups also recognize light pollution as an important issue. For example, the Institution of Lighting Engineers in the UK provides information to its members about light pollution, its problems, and how to mitigate its impact. Although, recent research has shown that energy efficiency is not sufficient to reduce light pollution due to the rebound effect.

Since not everyone is distracted by the same lighting source, it is common to "pollute" a person's light into a desired light for others. One example of this is found in ads, when advertisers want certain lights to be bright and visible, though others find them annoying. Other types of light pollution are more certain. For example, light that accidentally crosses the property boundary and disturbs the neighbor is generally wasted and polutive.

Disputes are still common when deciding the right course of action; and disagreements over what is considered fair, and who should be held accountable, means that negotiations must sometimes take place between the parties. Where objective measurements are desired, the level of light can be quantified by field measurements or mathematical modeling, with results typically displayed as isofote maps or light contour maps. The authorities have also taken various steps to deal with light pollution, depending on the interests, beliefs and understanding of the people involved. Sizes range from doing nothing, to implementing strict laws and regulations on how lamps can be installed and used.

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Type

Light contamination is a broad term that refers to a variety of issues, all of which are caused by the use of inefficient, unattractive, or (unquestionably) artificial light. The specific categories of light pollution include light violations, excessive lighting, glare, light complexity, and the ceiling. An offensive light source often falls into more than one of these categories.

Light takedown

Mild carelessness occurs when unwanted light enters a person's property, for example, by irradiating a neighbor's fence. A common problem of mild violations occurs when a strong light enters a person's window from outside, causing problems such as lack of sleep. A number of US cities have developed standards for outdoor lighting to protect citizens' rights against minor offenses. To help them, the International Dark-Sky Association has developed a set of light-lighting models.

The Dark-Sky Association begins to reduce the rising light to the sky which reduces star visibility (see Skyglow below). This is the light emitted over 90 ° above the nadir. By limiting the light at this 90 ° mark, they also reduce the light output in the 80-90 ° range that creates most of the problem of light aberrations.

US federal agencies may also uphold standards and process complaints within their jurisdiction. For example, in the case of light infractions by white strobe lighting from communications towers that exceed FAA minimum lighting requirements, the Federal Communications Commission maintains the Antenna Structure Registration database information that citizens can use to identify offensive structures and provide mechanisms for processing citizen inquiries. and complaints. The US Green Building Council (USGBC) also includes credits to reduce the number of light and sky light violations into their environmentally friendly building standards known as LEED.

Light breakthroughs can be reduced by selecting lights that limit the amount of light emitted over 80 ° above the nadir point. The IESNA definition includes full cutoffs (0%), cutoffs (10%), and semi-cutoffs (20%). (This definition also includes a light beam emitted above 90 ° to reduce the light of the sky.)

Overflow

Excessive lighting is the use of excessive light. Particularly in the United States, excessive lighting is responsible for about two million barrels of oil per day in wasted energy. This is based on US consumption equivalent to 18.8 million barrels per day (2,990,000 m ³ /d) petroleum. It is further noted at the same US Department of Energy Sources that more than 30% of all primary energy is consumed by the commercial, industrial and residential sectors. The energy audit of existing buildings shows that the lighting components of residential, commercial and industrial use consume about 20-40% of the land use, variable by region and land use. (Residential usage lighting consumes only 10-30% of energy bills while the main use of commercial buildings is illumination.) Thus lighting energy contributes about four or five million barrels of oil (equivalent) per day. Again, energy audit data show that about 30-60% of energy consumed in lighting is unnecessary or unreasonable.

Alternative calculations begin with the fact that commercial building lighting consumes more than 81.68 terawatt (data 1999) of electricity, according to the US DOE. So commercial lighting alone spends about four to five million barrels per day (equivalent) of petroleum, in line with the above alternative reasons for estimating the energy consumption of US lighting. Even among developed countries there is a big difference in light usage patterns. American cities emit 3-5 times more light for space per capita compared to German cities.

Excessive lighting comes from several factors:

• Consensus-based standards or norms that are not based on the science of vision;
• Do not use timers, occupancy sensors, or other controls to turn off lighting when not needed;
• Improper design, by setting a higher level of light than is required for a particular visual task;
• Incorrect lamp or lamp selection, which does not direct the light to the required area;
• Improper hardware selection to harness more energy than is needed to complete lighting tasks;
• Incomplete training to build managers and occupants to use lighting systems efficiently;
• Inadequate lighting maintenance results in increased light and lost energy costs;
• "Daylight lighting" requested by citizens to reduce crime or by shopkeepers to attract customers;
• Replacement of old lamps with more efficient LEDs using the same electrical power; and
• Indirect lighting techniques, such as illuminating the vertical wall to reflect light to the ground.

Much of this problem can be fixed immediately with available, inexpensive, and residential practice owner/tenant technologies that create barriers to the rapid correction of this issue. Most importantly, public awareness will need to be improved for industrialized countries to realize great results in reducing excessive illumination.

In some cases excess lighting lighting techniques may be required. For example, indirect lighting is often used to get a "softer" look, because hard direct lighting is generally found less desirable for specific surfaces, such as skin. The indirect lighting method is considered more convenient and in line with bars, restaurants and residences. It is also possible to block direct lighting effects by adding a softening filter or other solution, although the intensity will decrease.

Glare

Glare can be categorized into various types. One such classification is described in a book by Bob Mizon, coordinator for the British Astronomy Association's Campaign for the Dark Skies, as follows:

• Blinding glare describes the effect as caused by staring into the Sun. It's really blinding and leaving a temporary or permanent vision deficiency.
• Glare defects describes effects such as being blinded by an approaching car light, or light scattering in the fog or in the eye, reduces contrast, as well as reflections from prints and other dark areas that make it brighter, with significant reductions in the ability of vision.
• Glare discomfort usually does not cause a dangerous situation, though it's annoying and irritating. This can potentially cause fatigue if experienced in the long term.

According to Mario Motta, president of the Massachusetts Medical Society, "... the glare from bad lighting is a public health hazard - especially your older ones.Glare light scattering in the eye causes a loss of contrast and leads to unsafe driving conditions, dirty front from low-angle sunlight or high rays from an oncoming car. "In essence bright lights and/or sheltered around the road can cause the driver or pedestrian blind backward and contribute to accidents.

The dazzling effect is largely due to the reduction in contrast due to light scattering in the eye by excessive brightness, or light reflections from dark areas in the field of vision, with luminance similar to background lighting. This kind of glare is a special example of glare dislike, called the veil of hijab. (This is not the same as the loss of night vision accommodation caused by the direct effect of the light itself on the eye.)

Light commotion

Mild complexity refers to the clustering of excessive light. Lamp groupings can generate confusion, distract from obstacles (including those that might be intended to illuminate), and potentially cause accidents. Clutter is visible in the streets where streetlights are poorly designed, or where brightly lit advertisements surround the highway. Depending on the motives of the person or organization that installed the lamp, its placement and design can even be aimed at distracting the driver, and may contribute to the accident.

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Global measurements and effects

Measuring the effects of skylight on a global scale is a complicated procedure. The natural atmosphere is not completely dark, even without the light source and illumination of the Moon. This is caused by two main sources: airglow and scattered light .

At high altitudes, especially above the mesosphere, there is enough UV radiation from the sun with very short wavelengths to cause ionization. When the ions collide with the electric neutral particles they recombine and emit photons in the process, causing airflow. The ionization rate is large enough to allow constant emission of radiation even at night when the upper atmosphere is in Earth's shadow. Lower in the atmosphere all solar photons with energies above the ionization potentials N ₂ and O ₂ have been absorbed by higher layers and thus there is not enough ionization to occur.

In addition to emitting light, the sky also spreads the incoming light, especially from distant stars and the Milky Way, but also the zodiac, reflected sunlight and backscattered from interplanetary dust particles.

The amount of freshwater and zodiac light varies considerably (depending on, among others, on sunspot activity and solar cycles) but given the optimum conditions of the darkest sky has a brightness of about 22 magnitude/square arcsecond. If the full moon is present, the sky's brightness increases to about 18 magnitude/sq. arcsecond depends on the transparency of the local atmosphere, 40 times brighter than the darkest sky. In densely populated areas, the sky's brightness is 17 magnitude/sq. arcsecond unusual, or as much as 100 times brighter than natural.

To measure how bright the sky is, the Earth night satellite imagery is used as a raw input for the amount and intensity of light sources. These are incorporated into physical scattering models because of air and aerosol molecules to calculate the cumulative sky brightness. Maps showing improved sky brightness have been set up for the world.

Inspection areas around Madrid reveal that the effects of light pollution caused by a single large conglomerate can be felt up to 100 km (62 miles) from the center. The global effects of light pollution are also made clear. The entire area of ​​southern England, the Netherlands, Belgium, West Germany and northern France has a sky brightness of at least 2 to 4 times above normal (see top right). The only place on the continent of Europe where the sky can reach its natural darkness is in northern Scandinavia and on the distant islands of the continent.

In North America the situation is comparable. There are significant problems with light pollution ranging from Canada's Maritime Provinces to Southwest America. The International Dark-Sky Association works to establish areas with high-quality night sky. This area is supported by communities and organizations dedicated to reducing light pollution (eg, rescue of ceilings). National Park Service Natural Sounds and Night Skies Division have measured the quality of the night sky in national park units throughout the US. Sky quality in the US ranges from pure (Capitol Reef National Park and Big Bend National Park) to heavy degradation (National Recreation Santa Monica Mountains) Area and Biscayne National Park). The Sky Sky National Park Scanning Database is available online (2015).

Light pollution in Hong Kong was declared the 'worst on the planet' in March 2013.

As of June 2016, it is estimated that one-third of the world's population can no longer see the Milky Way, including 80% of Americans and 60% of Europeans. Singapore is found as the most polluted light country in the world.

src: inhabitat.com

Consequences

Effects on human health and psychology

Medical research on the effects of excessive light on the human body suggests that adverse health effects can be caused by light pollution or excessive light exposure, and some lighting design textbooks use human health as an explicit criterion for proper interior lighting. The health effects of excessive lighting or improper light composition may include: increased incidence of headaches, worker fatigue, medically determined stress, decreased sexual function and anxiety increase. Likewise, animal models have been studied showing unavoidable light to produce adverse effects on mood and anxiety. For those who need to be awake at night, the light at night also has an acute effect on alertness and mood.

In 2007, "work shifts involving circadian disorders" were listed as possible carcinogens by the International Agency for International Cancer Research of the World Health Organization. (IARC Press release No. 180). Several studies have documented the correlation between night shift work and increased incidence of breast and prostate cancers. One study examining the association between exposure to artificial light at night (ALAN) and breast cancer rates in South Korea found that areas with the highest levels of ALAN reported the highest number of cases of breast cancer. Seoul, which has the highest levels of light pollution, has 34.4% more cases of breast cancer than Ganwon-do, which has the lowest light pollution levels. This shows a high correlation between ALAN and the prevalence of breast cancer. It was also found that there was no correlation between other types of cancer such as cervical cancer or lung and ALAN levels.

A newer discussion (2009), written by Professor Steven Lockley, Harvard Medical School, can be found in CfDS's "Blinded by the Light?" Handbook. Chapter 4, "human health implications of light pollution" states that "... light intrusion, even if dim, tends to have a measurable effect on sleep disturbance and melatonin suppression.Even if this effect is relatively small from night to night, chronic continuous circadianity , sleep and hormonal disorders can have long-term health risks ". The New York Academy of Science held a meeting in 2009 about Circadian Disruption and Cancer. The red light suppresses the least melatonin.

In June 2009, the American Medical Association developed a policy to support the control of light pollution. News of the decision emphasized the glare as a public health hazard leading to unsafe driving conditions. Especially in the elderly, the glare produces a loss of contrast, obscuring night vision.

Ecosystem Disorder

When artificial light affects organisms and ecosystems, it is called ecological light pollution. While light at night can be beneficial, neutral, or destructive to individual species, its presence always disrupts the ecosystem. For example, some species of spiders avoid the burning area, while other species like to build their spider webs directly on lamp posts. Because the lamppost attracts many flying insects, the spider who does not mind the light, gets an advantage over the spider that avoids it. This is a simple example of the way in which frequencies and food webs can be disrupted by the introduction of night light.

Light pollution poses a particularly serious threat to night wildlife, has a negative impact on plant and animal physiology. This can confuse animal navigation, change competitive interactions, change predator-prone relationships, and cause psychological damage. The rhythms of life are governed by the natural patterns of light and darkness, so that interference with these patterns affects ecological dynamics.

Studies show that light pollution around the lake prevents zooplankton, such as Daphnia, from eating surface algae, causing algal blooms that can kill lake plants and degrade water quality. Light pollution can also affect ecosystems in other ways. For example, lepidopterists and entomologists have documented that nighttime light may interfere with the ability of moths and other nocturnal insects to navigate. Flowers that bloom at night that depend on moths for pollination may be affected by night lighting, as there are no pollinator substitutes that will not be affected by artificial light. This can lead to the decline of non-reproducing plant species, and change the long-term ecology. Among the night insects, fireflies (Coleoptera: Lampyridae, Phengodidae e Elateridae) are very interesting research objects for light pollution, once they rely on their own light to reproduce and, consequently, are very sensitive to light-level environments. In 2015 is shown and quantified for the first time the negative effects of direct illumination on fireflies, in a study that monitored the population for four years. Fireflies are charismatic (which is a rare quality among insects) and easily found by nonexperts, providing excellent species that are so good to attract the public's attention; a good investigative model for the effects of light on nocturnal wildlife; and ultimately, due to their sensitivity and rapid response to environmental changes, a good bioindicator for artificial night lighting.

A 2009 study also showed a devastating impact on animals and ecosystems due to polarized light interference or artificial light polarization (even during the day, as the natural polarization direction of sunlight and its reflections is a source of information for many animals). This form of pollution is called polarization of polarized light (PLP). Natural polarized light sources can trigger maladaptive behavior in polarization-sensitive taxa and alter ecological interactions.

Lights on tall structures can cause migratory birds disorientation. Estimates by the US Fish and Wildlife Service about the number of birds killed after being attracted to high towers ranging from 4 to 5 million per year to an even higher order. The Fatal Light Awareness Program (FLAP) works with building owners in Toronto, Ontario, Canada and other cities to reduce bird deaths by turning off lights during the migration period.

Similar disorientation has also been noted for migratory bird species close to offshore production and drilling facilities. A study by Nederlandse Aardolie Maatschappij b.v. (NAM) and Shell have led to the development and experiments of new lighting technologies in the North Sea. In early 2007, the lights were installed on the L15 Shell production platform. The experiment proved to be a huge success as the number of birds that surround the platform decreased by 50 to 90%.

Captive breeding of turtles emerging from nests on the coast is another victim of light pollution. It is a common misconception that hatching sea turtles are attracted to the moon. Instead, they find the ocean by moving away from the dark silhouettes of the dunes and their vegetation, a behavior that disrupts artificial lights. The breeding and reproduction activities of frog physiology, however, are characterized by moonlight. Juvenile seabirds may also be confused with lights as they leave their nests and fly into the sea. Amphibians and reptiles are also affected by light pollution. Light sources introduced during normal dark periods can disrupt melatonin production rates. Melatonin is a hormone that regulates physiology and photoperiodic behavior. Some species of frogs and salamanders use a light-dependent "compass" to direct their migratory behavior to breeding sites. Introduced light can also cause developmental disorders, such as retinal damage, reduced sperm production, and genetic mutations.

In September 2009, the 9th European Dark-Sky Symposium in Armagh, Northern Ireland held a session on the environmental effects of night light (LAN). It deals with bats, turtles, LAN "hidden" dangers, and many other topics. The environmental impact of the LAN was mentioned in early 1897, in the Los Angeles Times article. The following is an excerpt from the article, entitled "Electrical and English singer":

The English journal became concerned about the electrical connection with the singer bird, which guarded it closer than the cats and fodder plants. How many of us, he asked, predicted that electricity could wipe out the singers?... With the exception of finch birds, all English singers can be said to be insectivorous eaters, and their diet consists mainly of the large number of small insects they collect from the grass and plants before the dew dries. When the electric light found its way to street lighting to the states of England, these poor winged atoms were killed by thousands in every light every warm summer night.... Fear was expressed, that when the English was lit from one end. to another with electric birds the song will die due to the failure of their food supply.

Effects on astronomy

Astronomy is very sensitive to light pollution. The night sky seen from a city has no resemblance to what can be seen from the dark sky. Skyglow (the spread of light in the atmosphere) reduces the contrast between the star and the galaxy and the sky itself, making it more difficult to see dim objects. This is one of the factors that led to new telescopes built in increasingly remote areas. Some astronomers use a narrow "nebula filter" that only allows certain wavelengths of light commonly seen in nebulae, or "wide band light" noise filters designed to reduce (but not eliminate) the effects of light pollution by filtering the spectral lines generally emitted by sodium-and mercury-steam lamps, thereby enhancing contrast and increasing the dim view of objects such as galaxies and nebulae. Unfortunately this light pollution reduction filter (LPR) is not a drug for light pollution. The LPR filter reduces the brightness of the object under study and this limits the use of higher magnification. LPR filters work by blocking light from certain wavelengths, which change the color of an object, often creating a spoken green casts. Furthermore, LPR filters work only on certain types of objects (especially emission nebulae) and are only little used in galaxies and stars. No filter can match the effectiveness of the dark sky for visual or photographic purposes. Due to its low surface brightness, the visibility of dispersed sky objects such as nebulae and galaxies is influenced by light pollution over stars. Most of these objects are not seen in the heavily polluted skies around the big cities. A simple method to estimate the darkness of a location is to find the Milky Way, which from the really dark sky looks bright enough to form a shadow.

In addition to skyglow, a minor offense may affect the observation when artificial light directly enters the telescope tube and is reflected off the non-optical surface until it reaches the eyepiece. This direct form of light pollution causes light in the field of view which reduces contrast. Light carelessness also makes it difficult for visual observers to become dark enough to adapt. The usual steps to reduce this glare, if reducing the light directly is not an option, including a dash of telescope tubes and accessories to reduce the reflection, and put a light shield (can also be used as a dew shield) on the telescope to reduce the incoming light from an angle other than those close to the target. Under these conditions, some astronomers prefer to observe under black fabric to ensure maximum dark adaptation.

Increased air pollution

A study presented at a meeting of the American Geophysical Union in San Francisco found that light pollution destroys nitrate radicals thereby preventing the reduction of normal night time from atmospheric haze generated by smoke emitted from cars and factories. The study was presented by Harald Stark of the National Oceanic and Atmospheric Administration.

Reduction of natural sky polarization

At night, the polarization of the moonlit sky is greatly reduced by the presence of urban light pollution, because the scattered city light is not strongly polarized. The polarized moon rays can not be seen by humans, but are believed to be used by many animals for navigation.

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Reductions

Reducing light pollution implies many things, such as reducing sky light, reducing glare, reducing light violations, and reducing chaos. The method for reducing light pollution well, therefore, depends on what the problem is in the given example. Possible solutions include:

• Utilize light sources with the minimum intensity required to achieve light objectives.
• Shut down the light using a timer or occupancy sensors or manually when not needed.
• Fixed lighting fixtures, so they direct their light more accurately in the direction needed, and with fewer side effects.
• Adjust type of the lamp used, so the emitted light waves are less likely to cause severe light pollution problems. Mercury, metal halides and above all first generation blue LED lighting luminaires are much more polluting than sodium lamps: Earth's atmosphere diffuses and emits blue light better than yellow or red light. It is a common experience to observe "glare" and "fog" around and below the LED lighting luminaire as soon as the air humidity increases, while the orange light luminaire luminaires are less susceptible to indicate this phenomenon.
• Evaluate existing lighting plans, and redesign some or all of the packages depending on whether the light is really needed.

Fixed lighting fixtures

Use of full cutoff lighting fixtures, as much as possible, is recommended by most campaign users to reduce light pollution. It is also generally recommended that the lamp be properly positioned for maximum efficiency, and that the amount of luminaires used and the watt of each luminaire correspond to the specific application requirements (based on local lighting design standards).

The first full cutoff equipment was available in 1959 with the introduction of the General Electric M100 equipment.

The complete cutoff equipment, when properly installed, reduces the chance of light to loose above the horizontal plane. Light released above the horizontal can sometimes illuminate the intended target, but often has no purpose. When it enters the atmosphere, light contributes to the sky light. Some governments and organizations now consider, or have implemented, full cutoff fixtures in streetlights and stadium lights.

The use of full cutoff equipment helps reduce the sky light by preventing the light from escaping above the horizontal. Full cutoff usually reduces the visibility of lights and reflectors in the luminaire, so the glare effect is also reduced. The campaigners also generally argue that full cutoff equipment is more efficient than other equipment, because light that if not released into the atmosphere may be directed to the ground. However, full cutoff fixtures can also trap more light in the fixture than other luminaire types, according to the lower luminaire efficiency, suggesting the redesign of some luminaires may be required.

The use of full cutoff equipment can allow lower wattage lamps to be used in equipment, producing the same or sometimes better effects, as they are more carefully controlled. In every lighting system, some sky light is also generated from light reflected from the ground. This reflection can be reduced, however, by being careful to use only the lowest wattage required for the lamp, and setting the spacing of lights appropriately. Ensuring luminaire retreats greater than 90 ° from highly reflective surfaces also reduces reflections.

The general criticism of the cut-off lighting equipment is that they are sometimes not aesthetically pleasing to look at. This is most likely because historically there has not been a large market specifically for full cutoff equipment, and because people usually like to see the source of illumination. Due to its specificity with the direction of their light, full cutoff fixtures sometimes also require expertise to install for maximum effect.

The effectiveness of using full cutoff streetlights to combat light pollution has also been questioned. According to the design inquiry, luminaires with full cutoff distributions (as opposed to cutoff or semi cutoff, as opposed to here) should be closer together to meet the same light level, uniformity and glare requirements determined by IESNA. This simulation optimizes the height and distance of the lamp while limiting the overall design to meet IESNA requirements, and then compares the total uplight and energy consumption of the design and strength of different luminaires. The cutoff design performs better than the full cutoff design, and the semi-performing cutoff is better than a full cutoff or cutoff. This suggests that, in road installations, excessive illumination or poor uniformity produced by full cutoff equipment may be more detrimental than direct spotlights made by fewer cutoffs or semi-cutoff fixtures. Therefore, the overall performance of existing systems can be increased more by reducing the number of luminaires than by switching to full cutoff designs.

However, using the definition of "light pollution" from some Italian regional bills (ie, "any artificial light radiation outside the area of ​​competence and especially to the top of the sky") only full cutoff design prevents light pollution. The Lombardy region of Italy, where only a full cutoff design is allowed (the action of Lombardy No. 17/2000, promoted by Cielobuio-coordination for the protection of the night sky), in 2007 had the lowest per capita energy consumption for general illumination in Italy. The same law also sets the minimum distance between the streetlights about four times their height, so cutting the streetlights is the best solution to reduce light pollution and the use of electrical power.

Adjust the type of light source

Several different types of light sources exist, each having different properties that affect their eligibility for specific tasks, particularly the efficiency and distribution of spectral power. Often inappropriate light sources have been selected for a task, either out of ignorance or because more sophisticated light sources are not available during installation. Therefore, poorly selected light sources often contribute unnecessarily to light pollution and energy wastage. By reassessing and changing the light source used, it can often reduce energy use and pollution effects while simultaneously improving efficiency and visibility.

Several types of light sources are listed in the energy efficiency sequence in the table below (numbers are estimates maintained), and include the relative visual skyglow impact.

Many astronomers request that nearby communities use low-pressure sodium lamps or amber Aluminum gallium indium phosphide LEDs as much as possible, since the primary wavelengths emitted are quite easy to do or in filtered rare cases. Low cost to operate sodium lamp is another feature. In 1980, for example, San Jose, California, replaced all streetlights with low-pressure sodium lamps, whose light was easier near the Lick Observatory for screening. Similar programs now exist in Arizona and Hawaii. Such yellow light sources also have far less visual skyglow effects, thereby reducing the visual brightness of the sky and increasing the star visibility for everyone.

Lack of low-pressure sodium lighting is a device that usually has to be larger than competing equipment, and the color is indistinguishable, because it emits essentially one wavelength of light (see security lighting). Due to the large size of the lamp, especially in higher watts such as 135 W and 180 W, light emission control of low pressure sodium luminaires is more difficult. For applications requiring more precise light direction (such as narrow paths) the original lamp's excellence is decreasing and may be completely lost compared to high-pressure sodium lamps. The allegation that this also leads to the high amount of light pollution from luminaires that run these lights mainly because of the older luminaires with bad shields, still widely used in the UK and in some other locations. Low-pressure modern sodium fixtures with better optics and full shields, and a decrease in the skyglow effect of yellow light keep the glowing efficacy advantage of low-pressure sodium and result in most cases being less energy consumption and less visible light pollution. Unfortunately, due to the lack of accurate information, many lighting professionals continue to underestimate low-pressure sodium, contributing to the decrease in acceptance and specifications in lighting standards and therefore their use. Another disadvantage of low-pressure sodium lamps is that some people find that typical yellow light is very aesthetically unpleasant.

Due to the increased sensitivity of the human eye to blue and green wavelengths at the sight of low luminitas (Purkinje effect) in the night sky, different sources produce the amount of sky light that looks very different from the same amount of light sent into the atmosphere.

Redesigning the lighting plan

In some cases, evaluation of existing plans has determined that more efficient lighting plans are possible. For example, light pollution can be reduced by turning off unneeded outer lights, and only turning on the stadium when there are people in it. Timers are very valuable for this purpose. One of the world's first coordinated legislative efforts to reduce the environmental impact of this pollution begins in Flagstaff, Arizona, in the US. There, over the past three decades the development of the ordinance has taken place, with full population support, often with government support, with community advocacy, and with the help of key local observatories, including Flagstaff Station of the United States Marine Observatory. Each component helps to educate, protect and enforce the imperative to intelligently reduce harmful light pollution.

One example of a lighting plan assessment can be seen in the report originally commissioned by the Office of the Deputy Prime Minister in the United Kingdom, and is now available through the Department for Communities and Local Government. This report details plans that will be applied throughout the UK, to design rural lighting schemes, with a particular focus on environmental conservation.

In another example, the city of Calgary recently replaced most of the residential streetlights with an energy-efficient model. The main motivation is the cost of operation and environmental conservation. Installation costs are expected to be recovered through energy savings in six to seven years.

The Swiss Agency for Energy Efficiency (AMAN) uses promising concepts that will be of great use in the diagnosis and design of street lighting, " consommation ÃÆ'  © lectrique spà © cifique ( CES )" , which can be translated into English as "specific electrical power consumption (SEC)". Thus, based on the level of illumination observed in various Swiss cities, SAFE has set target values ​​for the consumption of electric power per meter for various category roads. So, SAFE currently recommends SEC 2 to 3 watts per meter for roads with widths less than 10 meters (4 to 6 watts per meter for wider roads). Such measures provide easy-to-apply environmental protection limits on conventional "norms," ​​which are usually based on recommendations from the lighting manufacturing interests, which may not take into account environmental criteria. Given the ongoing advances in lighting technology, SEC target targets need to be periodically revised downwards.

New methods for predicting and measuring various aspects of light pollution are described in the journal Lighting Research Technology (September 2008). Scientists at Rensselaer Polytechnic Institute's Lighting Research Center have developed a comprehensive method called Outdoor Site-Lighting Performance (OSP), which enables users to measure, and thus optimize, the performance of existing and planned lighting designs and applications to minimize excessive light leaving or stands out the boundaries of a property. OSP can be used by lighting engineers soon, especially for light investigations and violations (more complex glare analyzes to do and commercial software are not currently easy to enable them), and can help users compare multiple lighting design alternatives for the same site.

In an effort to reduce light pollution, researchers have developed the "Integrated Photometric System", which is a way to measure how much or what kind of street lighting is needed. The Unified System of Photometry allows lights designed to reduce energy use while maintaining or improving perceptions of visibility, security, and security. There is a need to create a new light measurement system at night because of the biological way in which the eye shaft and cone light process differ in nighttime conditions compared to daytime conditions. Using this new photometry system, results from recent research indicate that replacing traditional, yellow, high-pressure sodium (HPS) lamps with "cold" white light sources, such as induction, fluorescent, ceramic metal halides, or LEDs can actually reduce the amount of power electricity used for lighting while maintaining or improving visibility in nighttime conditions.

Source of the article : Wikipedia