A composite satellite image of the Earth at night. Few naturally dark areas remain on the land surface of the Earth.
A composite satellite image of the Earth at night. Few naturally dark areas remain on the land surface of the Earth.
An urban park (Ibirapuera Park, Brazil) at night
An urban park (Ibirapuera Park, Brazil) at night

Ecological light pollution[1] is the effect of artificial light on individual organisms and on the structure of ecosystems as a whole.

The effect that artificial light has upon organisms is highly variable,[2] and ranges from beneficial (e.g. increased ability for predator species to observe prey) to immediately fatal (e.g. moths that are attracted to incandescent lanterns and are killed by the heat). It is also possible for light at night to be both beneficial and damaging for a species. As an example, humans benefit from using indoor artificial light to extend the time available for work and play, but the light disrupts the human circadian rhythm, and the resulting stress is damaging to health.[3][4]

Through the various effects that light pollution has on individual species, the ecology of regions is affected. In the case where two species occupy an identical niche, the population frequency of each species may be changed by the introduction of artificial light if they are not equally affected by light at night. For example, some species of spiders avoid lit areas, while other species willingly build webs directly on lamp posts. Since lamp posts attract many flying insects,[5] the spiders that tolerate light gain an advantage over the spiders that avoid it, and may become more dominant in the environment as a result.[6] Changes in these species frequencies can then have knock-on effects, as the interactions between these species and others in the ecosystem are affected and food webs are altered. These ripple effects can eventually affect diurnal plants and animals. As an example, changes in the activity of night active insects can change the survival rates of night blooming plants,[7] which may provide food or shelter for diurnal animals.

The introduction of artificial light at night is one of the most drastic anthropogenic changes to the Earth, comparable to toxic pollution, land use change, and climate change due to increases in the concentration of green house gases.

Light pollution can even affect the animals and plants active during the day, as these diurnal wasps that are stealing the nocturnal insects caught in spiderwebs near street lamps demonstrate.
Light pollution can even affect the animals and plants active during the day, as these diurnal wasps that are stealing the nocturnal insects caught in spiderwebs near street lamps demonstrate.

Natural light cycles

The introduction of artificial light disrupts several natural light cycles that arise from the movements of the Earth, Moon, and Sun, as well as from meteorological factors.

Diurnal (solar) cycle

The most obvious change in introducing light at night is the end of darkness in general. The day/night cycle is probably the most powerful environmental behavioral signal, as almost all animals can be categorized as nocturnal or diurnal. If a nocturnal animal is only active in extreme dark, it will be unable to survive in lit areas. The most acute affects are directly next to streetlights and lit buildings, but the diffuse light of skyglow can extend out to hundreds of kilometers away from city centres.

Seasonal (solar) cycles

The axial tilt of the Earth results in seasons outside of the tropics. The change in the length of the day, or photoperiod, is the key signal for seasonal behavior (e.g. mating season) in non-tropical animals and plants. The presence of light at night can result in "seasons out of time",[8] changing the behavior, thermoregulation, and hormonal functioning of affected organisms. This may result in a disconnect between body functioning and seasonality, causing disruptions to reproduction, dormancy, and migration.

Lunar cycles

The behavior of some animals (e.g. coyotes,[9] bats,[10] toads,[11] insects) is keyed to the lunar cycle. Near city centers the level of skyglow often exceeds that of the full moon,[12] so the presence of light at night can alter these behaviors, potentially reducing fitness.

Cloud coverage

In pristine areas, clouds blot out the stars and darken the night sky, resulting in the darkest possible nights. In urban and suburban areas, in contrast, clouds enhance the effect of skyglow,[12] particularly for longer wavelengths.[13] This means that the typical level of light is much higher near cities, but it also means that truly dark nights never occur in these areas.

The impact of clouds on light levels in urban and suburban ecosystems is completely reversed from what occurs in pristine areas.
The impact of clouds on light levels in urban and suburban ecosystems is completely reversed from what occurs in pristine areas.

Effects of light pollution on individual organisms

Terrestrial Environment

Insects

The attraction of insects to artificial light is one of the most well known examples of the effect of light at night on organisms. When insects are attracted to lamps they can be killed by exhaustion or contact with the lamp itself, and they are also vulnerable to predators like bats.[5]

Insects are affected differently by the varying wavelengths of light, and many species can see ultraviolet and infrared light that is invisible to humans. Because of variances in perception, moths are more attracted to broad spectrum white and bluish light sources than they are to the yellow light emitted by low pressure sodium-vapor lamps.[14]

Insects killed by attraction to a buried light box.
Insects killed by attraction to a buried light box.

The compound eye of moths results in fatal attraction to light.[15]

Dragonflies perceive horizontally polarized light as a sign of water. For this reason, sources of water are indistinguishable from asphalt roads with polarized light pollution to them. Dragonflies searching for water either to drink or in which to lay eggs often land on roads or other dark flat reflective surfaces such as cars and remain there until they die of dehydration and hyperthermia.[16]

Light pollution may hamper the mating rituals of fireflies, once they depend on their own light for courtship, resulting in decreased populations.[17][18][19]

Fireflies are charismatic (which is a rare quality amongst insects) and are easily spotted by nonexperts, providing thus good flagship species to attract public attention; good investigation models for the effects of light on nocturnal wildlife; and finally, due to their sensibility and rapid response to environmental changes, good bioindicators for artificial night lighting.[20]

Birds

See also: Bird-skyscraper collisions

Lights on tall structures can disorient migrating birds leading to fatalities. An estimated 365-988 million fatal bird collisions with buildings occur annually in North America, making human-made structures a large contributor to the decline in bird species.[21] The surface area of glass emitting artificial light at night is a major factor for fatal bird collisions with buildings, and turning off lights at night can minimize these fatalities.[22] The Fatal Light Awareness Program (FLAP) works with building owners in Toronto, Canada and other cities to reduce mortality of birds by turning out lights during migration periods.

Migratory birds confused by the World Trade Center memorial searchlights.
Migratory birds confused by the World Trade Center memorial searchlights.

Similar disorientation has also been noted for bird species migrating close to offshore production and drilling facilities. Studies carried out by Nederlandse Aardolie Maatschappij b.v. (NAM) and Shell have led to development and trial of new lighting technologies in the North Sea. In early 2007, the lights were installed on the Shell production platform L15. The experiment proved a great success since the number of birds circling the platform declined by 50–90%.[56] Juvenile seabirds may also be disoriented by lights as they leave their nests and fly out to sea.[23]

Brazil star trails and birds in light pollution photography in Rio beach at night
Brazil star trails and birds in light pollution photography in Rio beach at night
jBirds flying trace and star trail near Rio de Janeiro beach at night time in light pollution
jBirds flying trace and star trail near Rio de Janeiro beach at night time in light pollution

Birds migrate at night for several reasons. Save water from dehydration in hot day flying and part of the bird's navigation system works with stars in some way. With city light outshining the night sky, birds (and also about mammals) no longer navigate by stars.[24]

Ceilometers (searchlights) can be particularly deadly traps for birds,[25] as they become caught in the beam and risk exhaustion and collisions with other birds. In the worst recorded ceilometer kill-off, on October 7–8, 1954, 50,000 birds from 53 different species were killed at Warner Robins Air Force Base.[26]

Turtles

Lights from seashore developments repel nesting Sea turtle mothers, and their hatchlings are fatally attracted to street and hotel lights rather than to the ocean.[27]

Plants

Artificial lighting has many negative impacts on trees and plants, particularly in fall and autumn phenology. Trees and herbaceous plants rely on the photoperiod, or the amount of time in a day where sunlight is available for photosynthesis, to help determine the changing seasons. When the hours of sunlight decrease, plants can recognize that autumn is underway and begin to make preparations for winter dormancy. For example, deciduous trees shift the colour of their leaves to maximize different wavelengths of light that are more prevalent in the fall before eventually dropping them as light becomes too scarce for photosynthesis to be worthwhile. When deciduous trees are exposed to light pollution, they mistake the artificial light for sunlight and retain their green leaves later into the autumn season. This can be dangerous for the tree, as it wastes energy trying to photosynthesize that should be preserved for winter survival. Light pollution can also cause leaf stoma to remain open into the night, which leaves the tree vulnerable to infection and disease.[28]

Similarly, light pollution in the spring can also be dangerous for trees and herbaceous plants. Artificial light causes plants to think that spring has arrived and it is time to begin producing leaves for photosynthesizing again. However, temperatures may not yet be warm enough to support the new leaf buds, and they are susceptible to frost, which can impair future leaf production. Small herbaceous plants that are exposed to artificial lighting potentially face a greater risk, as more of their body is illuminated. Therefore, only the root system is protected, and could potentially not be enough to sustain the whole plant as it tries to remain green through the fall and winter.[29]

Aquatic Environment

Zooplankton

Zooplankton (e.g. Daphnia) exhibit diel vertical migration. That is, they actively change their vertical position inside of lakes throughout the day. In lakes with fish, the primary driver for their migration is light level, because small fish visually prey on them. The introduction of light through skyglow reduces the height to which they can ascend during the night.[30] Because zooplankton feed on the phytoplankton that form algae, the decrease in their predation upon phytoplankton may increase the chance of algal blooms, which can kill off the lakes' plants and lower water quality.

Fish

Light pollution impacts migration in some species of fish. For example, juvenile chinook salmon are attracted to and slowed down by artificial light. It is possible that artificial light draws them closer to the shoreline, where they face a greater risk of predation from birds and mammals. Artificial lighting also attracts a greater density of piscivorous fish, which have an advantage due to the slower movement of the juvenile fish.[31] Light pollution also has impacts on the hormonal functioning of some fish; European perch and roach both experience reductions in the production of reproductive hormones when exposed to artificial lighting in a rural environment.[32] Artificial light has also been shown to cause disruptions to fish (and zooplankton) in the high Arctic, where fishing boats with lights resulted in a lack of fish up to 200 metres below the water's surface.[33]

Humans

At the turn of the century it was discovered that human eyes contain a non-imaging photosensor that is the primary regulator of the human circadian rhythm.[34] This photosensor is particularly affected by blue light, and when it observes light the pineal gland stops the secretion of melatonin. The presence of light at night in human dwellings (or for shift workers) makes going to sleep more difficult and reduces the overall level of melatonin in the bloodstream, and exposure to a low-level incandescent bulb for 39 minutes is sufficient to suppress melatonin levels to 50%.[4][35] Because melatonin is a powerful anti-oxidant, it is hypothesized that this reduction can result in an increased risk of breast and prostate cancer.[36][37]

Other human health effects may include increased headache incidence, worker fatigue, medically defined stress, decrease in sexual function and increase in anxiety.[38][39][40][41] Likewise, animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety.[42]

Effects of different wavelengths

The effect that artificial light has upon organisms is wavelength dependent. While human beings cannot see ultraviolet light, it is often used by entomologists to attract insects. Generally speaking, blue light is more likely to be damaging to mammals because the non-imaging photoreceptors in mammalian eyes are most sensitive in the blue region.[43] This means that if traditional vapor discharge streetlamps are replaced by white LEDs (which generally emit more of their radiation in the blue part of the spectrum), the ecological impact could be greater even if the total amount of radiated light is decreased.[44]

Polarized light pollution

Light pollution is mostly unpolarized, and its addition to moonlight results in a decreased polarization signal.
Light pollution is mostly unpolarized, and its addition to moonlight results in a decreased polarization signal.

Artificial planar surfaces, such as glass windows or asphalt reflect highly polarized light. Many insects are attracted to polarized surfaces, because polarization is usually an indicator for water. This effect is called polarized light pollution,[45] and although it is certainly a form of ecological photopollution, "ecological light pollution" usually refers to the impact of artificial light on organisms.

In the night, the polarization of the moonlit sky is very strongly reduced in the presence of urban light pollution, because scattered urban light is not strongly polarized.[46] Since polarized moonlight is believed to be used by many animals for navigation, this screening is another negative effect of light pollution on ecology.

Prevents and Controls

To regulate and manage the problem of light pollution, it needs to establish a mature management system. Based on Zhou's studies, posing regulations such as green lighting, strengthening the propaganda and education by governors could help stop or reduce the adverse impacts of light pollution.[47]

See also

References

  1. ^ Longcore, Travis; Rich, Catherine (2004). "Ecological light pollution". Frontiers in Ecology and the Environment. 2 (4): 191–198. doi:10.1890/1540-9295(2004)002[0191:elp]2.0.co;2. ISSN 1540-9295.
  2. ^ Catherine Rich; Travis Longcore (2006). Ecological consequences of artificial night lighting. Island Press. ISBN 978-1-55963-128-0.
  3. ^ Chepesiuk, R (2009). "Missing the Dark: Health Effects of Light Pollution". Environmental Health Perspectives. 117 (1): A20–7. doi:10.1289/ehp.117-a20. PMC 2627884. PMID 19165374.
  4. ^ a b Navara, KJ; Nelson (2007). "The dark side of light at night: physiological, epidemiological, and ecological consequences". J Pineal Res. 43 (3): 215–224. doi:10.1111/j.1600-079X.2007.00473.x. PMID 17803517. S2CID 11860550.
  5. ^ a b Rydell, J (1992). "Exploitation of Insects around Streetlamps by Bats in Sweden". Functional Ecology. 6 (6): 744–750. doi:10.2307/2389972. JSTOR 2389972.
  6. ^ Czaczkes, Tomer J.; Bastidas-Urrutia, Ana María; Ghislandi, Paolo; Tuni, Cristina (2018-10-30). "Reduced light avoidance in spiders from populations in light-polluted urban environments". The Science of Nature. 105 (11): 64. Bibcode:2018SciNa.105...64C. doi:10.1007/s00114-018-1589-2. ISSN 1432-1904. PMID 30377809. S2CID 53108567.
  7. ^ Gaston, Kevin J.; Bennie, Jonathan; Davies, Thomas W.; Hopkins, John (2013-04-08). "The ecological impacts of nighttime light pollution: a mechanistic appraisal". Biological Reviews. 88 (4): 912–927. doi:10.1111/brv.12036. ISSN 1464-7931. PMID 23565807. S2CID 5074170.
  8. ^ Haim, Abraham; Shanas, Uri; Zubidad, Abed El Salam; Scantelbury, Michael (2005). "Seasonality and Seasons Out of Time—The Thermoregulatory Effects of Light Interference". Chronobiology International. 22 (1): 59–66. doi:10.1081/CBI-200038144. PMID 15865321. S2CID 10616727.
  9. ^ Bender, Darren J; Bayne, Erin M; Brigham, R Mark (1996). "Lunar Condition Influences Coyote (Canis latrans) Howling". American Midland Naturalist. 136 (2): 413–417. doi:10.2307/2426745. JSTOR 2426745.
  10. ^ Gannon, Michael R; Willig, Michael R (1997). "The Effect of Lunar Illumination on Movement and Activity of the Red Fig-eating Bat (Stenoderma rufum)". Biotropica. 29 (4): 525–529. doi:10.1111/j.1744-7429.1997.tb00048.x. JSTOR 2388947. S2CID 85156702.
  11. ^ Rachel A. Granta; Elizabeth A. Chadwick; Tim Halliday (2009). "The lunar cycle: a cue for amphibian reproductive phenology?". Animal Behaviour. 78 (2): 349–357. doi:10.1016/j.anbehav.2009.05.007. S2CID 53169271.
  12. ^ a b C. C. M. Kyba; T. Ruhtz; J. Fischer; F. Hölker (2011). "Cloud Coverage Acts as an Amplifier for Ecological Light Pollution". PLOS ONE. 6 (3): e17307. Bibcode:2011PLoSO...617307K. doi:10.1371/journal.pone.0017307. PMC 3047560. PMID 21399694.
  13. ^ Kyba, C. C. M.; Ruhtz, T.; Fischer, J.; Hölker, F. (1 September 2012). "Red is the new black: how the colour of urban skyglow varies with cloud cover". Monthly Notices of the Royal Astronomical Society. 425 (1): 701–708. Bibcode:2012MNRAS.425..701K. doi:10.1111/j.1365-2966.2012.21559.x.
  14. ^ Gray, R. (29 May 2013). "Fatal Attraction: Moths Find Modern Street Lamps Irresistible". Online Newspaper. The Daily Telegraph. Archived from the original on May 29, 2013. Retrieved 15 November 2014.
  15. ^ Kenneth D. Frank (1988). "Impact of outdoor lighting on moths". Journal of the Lepidopterists' Society. 42: 63–93. Archived from the original on 2006-06-17.
  16. ^ "Polarized Light Pollution Leads Animals Astray". UPI Space Daily. United Press International. 13 January 2009.
  17. ^ Blinder, Alan (August 14, 2014). "The Science in a Twinkle of Nighttime in the South". The New York Times. Retrieved August 18, 2014.
  18. ^ Owens, Avalon Celeste Stevahn; Meyer-Rochow, Victor Benno; Yang, En-Cheng (2018-02-07). "Short- and mid-wavelength artificial light influences the flash signals of Aquatica ficta fireflies (Coleoptera: Lampyridae)". PLOS ONE. 13 (2): e0191576. Bibcode:2018PLoSO..1391576O. doi:10.1371/journal.pone.0191576. ISSN 1932-6203. PMC 5802884. PMID 29415023.
  19. ^ Firebaugh, Ariel; Haynes, Kyle J. (2016-12-01). "Experimental tests of light-pollution impacts on nocturnal insect courtship and dispersal". Oecologia. 182 (4): 1203–1211. Bibcode:2016Oecol.182.1203F. doi:10.1007/s00442-016-3723-1. ISSN 0029-8549. PMID 27646716. S2CID 36670391.
  20. ^ Viviani, Vadim Ravara; Rocha, Mayra Yamazaki; Hagen, Oskar (June 2010). "Bioluminescent beetles (Coleoptera: Elateroidea: Lampyridae, Phengodidae, Elateridae) in the municipalities of Campinas, Sorocaba-Votorantim and Rio Claro-Limeira (SP, Brazil): biodiversity and influence of urban sprawl". Biota Neotropica. 10 (2): 103–116. doi:10.1590/S1676-06032010000200013. ISSN 1676-0603.
  21. ^ Loss, Scott R.; Will, Tom; Loss, Sara S.; Marra, Peter P. (2014-02-01). "Bird–building collisions in the United States: Estimates of annual mortality and species vulnerability". The Condor. 116 (1): 8–23. doi:10.1650/CONDOR-13-090.1. ISSN 0010-5422. S2CID 11925316.
  22. ^ Lao, Sirena; Robertson, Bruce A.; Anderson, Abigail W.; Blair, Robert B.; Eckles, Joanna W.; Turner, Reed J.; Loss, Scott R. (January 2020). "The influence of artificial light at night and polarized light on bird-building collisions". Biological Conservation. 241: 108358. doi:10.1016/j.biocon.2019.108358. ISSN 0006-3207. S2CID 213571293.
  23. ^ RodrÍguez, Airam; RodrÍguez, Beneharo (2009). "Attraction of petrels to artificial lights in the Canary Islands: effects of the moon phase and age class". Ibis. 151 (2): 299–310. doi:10.1111/j.1474-919X.2009.00925.x. hdl:10261/45133.
  24. ^ "در سایه‌ی نور‌ها". پریسا باجلان (in Persian). 2020-10-15. Retrieved 2020-10-16.
  25. ^ http://www.staplenews.com/home/2010/9/16/10000-birds-trapped-in-the-world-trade-center-light-beams.html
  26. ^ Johnston, D; Haines (1957). "Analysis of Mass Bird Mortality in October, 1954". The Auk. 74 (4): 447–458. doi:10.2307/4081744. JSTOR 4081744.
  27. ^ M. Salmon (2003). "Artificial night lighting and sea turtles" (PDF). Biologist. 50: 163–168.[permanent dead link]
  28. ^ Škvareninová, Jana; Tuhárska, Mária; Škvarenina, Jaroslav; Babálová, Darina; Slobodníková, Lenka; Slobodník, Branko; Středová, Hana; Minďaš, Jozef (2017-12-01). "Effects of light pollution on tree phenology in the urban environment". Moravian Geographical Reports. 25 (4): 282–290. doi:10.1515/mgr-2017-0024. S2CID 73529155.
  29. ^ ffrench-Constant, Richard H.; Somers-Yeates, Robin; Bennie, Jonathan; Economou, Theodoros; Hodgson, David; Spalding, Adrian; McGregor, Peter K. (2016-06-29). "Light pollution is associated with earlier tree budburst across the United Kingdom". Proceedings of the Royal Society B: Biological Sciences. 283 (1833): 20160813. doi:10.1098/rspb.2016.0813. ISSN 0962-8452. PMC 4936040. PMID 27358370.
  30. ^ Marianne V. Moore; Stephanie M. Pierce; Hannah M. Walsh; Siri K. Kvalvik; Julie D. Lim (2000). "Urban light pollution alters the diel vertical migration of Daphnia" (PDF). Verh. Internat. Verein. Limnol. 27: 1–4.
  31. ^ Nelson, Thomas Reid; Michel, Cyril J.; Gary, Meagan P.; Lehman, Brendan M.; Demetras, Nicholas J.; Hammen, Jeremy J.; Horn, Michael J. (2021-02-16). "Effects of Artificial Lighting at Night on Predator Density and Salmonid Predation". Transactions of the American Fisheries Society. 150 (2): 147–159. doi:10.1002/tafs.10286. ISSN 0002-8487. S2CID 229392819.
  32. ^ Brüning, Anika; Kloas, Werner; Preuer, Torsten; Hölker, Franz (2018). "Influence of artificially induced light pollution on the hormone system of two common fish species, perch and roach, in a rural habitat". Conservation Physiology. 6 (1): coy016. doi:10.1093/conphys/coy016. ISSN 2051-1434. PMC 5905364. PMID 29686874.
  33. ^ Berge, Jørgen; Geoffroy, Maxime; Daase, Malin; Cottier, Finlo; Priou, Pierre; Cohen, Jonathan H.; Johnsen, Geir; McKee, David; Kostakis, Ina; Renaud, Paul E.; Vogedes, Daniel (2020-03-05). "Artificial light during the polar night disrupts Arctic fish and zooplankton behaviour down to 200 m depth". Communications Biology. 3 (1): 102. doi:10.1038/s42003-020-0807-6. ISSN 2399-3642. PMC 7058619. PMID 32139805.
  34. ^ Provencio, Ignacio; Rodriguez, Ignacio R.; Jiang, Guisen; Hayes, William Pär; Moreira, Ernesto F.; Rollag, Mark D. (2000). "A Novel Human Opsin in the Inner Retina". The Journal of Neuroscience. 20 (2): 600–605. doi:10.1523/JNEUROSCI.20-02-00600.2000. PMC 6772411. PMID 10632589.
  35. ^ Schulmeister, K.; Weber, M.; Bogner, W.; Schernhammer, E. (2002). "Application of melatonin action spectra on practical lighting issues". Final Report. The Fifth International LRO Lighting Research Symposium, Light and Human Health. Archived from the original on 2016-08-18. Retrieved 2016-08-01.
  36. ^ Scott Davis; Dana K. Mirick; Richard G. Stevens (2001). "Night Shift Work, Light at Night, and Risk of Breast Cancer". Journal of the National Cancer Institute. 93 (20): 1557–1562. doi:10.1093/jnci/93.20.1557. PMID 11604479.
  37. ^ Eva S. Schernhammer; Francine Laden; Frank E. Speizer; Walter C. Willett; David J. Hunter; Ichiro Kawachi; Graham A. Colditz (2001). "Rotating Night Shifts and Risk of Breast Cancer in Women Participating in the Nurses' Health Study". Journal of the National Cancer Institute. 93 (20): 1563–1568. doi:10.1093/jnci/93.20.1563. PMID 11604480.
  38. ^ Susan L. Burks, Managing your Migraine, Humana Press, New Jersey (1994) ISBN 0-89603-277-9
  39. ^ Cambridge Handbook of Psychology, Health and Medicine, edited by Andrew Baum, Robert West, John Weinman, Stanton Newman, Chris McManus, Cambridge University Press (1997) ISBN 0-521-43686-9
  40. ^ L. Pijnenburg, M. Camps and G. Jongmans-Liedekerken, Looking closer at assimilation lighting, Venlo, GGD, Noord-Limburg (1991)
  41. ^ Knez, I (2001). "Effects of Colour of Light on Nonvisual Psychological Processes". Journal of Environmental Psychology. 21 (2): 201–208. doi:10.1006/jevp.2000.0198.
  42. ^ Fonken, L K; Finy, M S; Walton, James C.; Weil, Zachary M.; Workman, Joanna L.; Ross, Jessica; Nelson, Randy J. (28 December 2009). "Influence of light at night on murine anxiety- and depressive-like responses". Behavioural Brain Research. 205 (2): 349–354. doi:10.1016/j.bbr.2009.07.001. PMID 19591880. S2CID 4204514.
  43. ^ Falchi, F; Cinzano P; Elvidge CD; Keith DM; Haim A (2011). "Limiting the impact of light pollution on human health, environment and stellar visibility". Journal of Environmental Management. 92 (10): 2714–2722. arXiv:2007.02063. doi:10.1016/j.jenvman.2011.06.029. PMID 21745709. S2CID 18988450.
  44. ^ International Dark-Sky Association (2010). "Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting" (PDF). IDA White Paper. Archived from the original (PDF) on 2011-08-14. Retrieved 2011-08-20.
  45. ^ Horváth, Gábor; György Kriska; Péter Malik; Bruce Robertson (August 2009). "Polarized light pollution: a new kind of ecological photopollution". Frontiers in Ecology and the Environment. 7 (6): 317–325. doi:10.1890/080129.
  46. ^ Kyba, C. C. M.; Ruhtz, T.; Fischer, J.; Hölker, F. (17 December 2011). "Lunar skylight polarization signal polluted by urban lighting". Journal of Geophysical Research. 116 (D24): n/a. Bibcode:2011JGRD..11624106K. doi:10.1029/2011JD016698.
  47. ^ Zhou, Xiaomei (2016). "Research On Light Pollution". Proceedings of the 2016 6th International Conference on Machinery, Materials, Environment, Biotechnology and Computer. Tianjin, China: Atlantis Press: 718–720. doi:10.2991/mmebc-16.2016.152. ISBN 978-94-6252-210-7.