470:
more effective than manipulating the spectrum of the light. Spectrum does play a role, but in order to prevent disturbance to sensitive animals, changes must be made to the spectrum which cannot be described by the G-index. Those changes are also species dependent. A specific (red-dominant) spectrum has been proven to be as good as darkness for many (but not all) light sensitive insect and bat species. An amber spectrum is proven to be less eco-friendly than a red spectrum for some species, although both have negligible blue content and âfavorableâ G index. Therefore the use of spectral G-index is overly simplistic and may do more harm than good. The use of the G-index is therefore strongly discouraged for use in lighting specifications or regulations.
90:
267:
350:, and therefore produces more artificial skyglow than an equivalent amount of longer wavelength light. Additionally, both broad spectrum (white) light and short wavelength light tend to have greater overall ecological impacts than narrow band and long wavelength visible light. For this reason, lighting guidelines, recommendations, norms, and
469:
A measure focused solely on reducing blue light will not provide ecological protection. Because the intensity of light plays a role as strong or stronger than spectrum, putting the light in the right places (on road surfaces and sidewalks) and avoiding spillage into ecological regions is likely to be
425:
of road lighting. Specifically, in areas needing protection for astronomical or ecological reasons, they recommend the use of the G-index instead of CCT in making lighting decisions, because the G-index more accurately quantifies the amount of blue light. In their "core criteria", they recommend that
465:
The G-index has not been evaluated or adopted by a standards development organization (SDO), such as the CIE. Generally, for a specification to be used in a regulation or tender, it must go through the rigorous process of evaluation and adoption by an SDO. It is thus questionable for the EC Joint
341:
lamps for street lighting to (mainly) white LEDs has resulted in a shift towards broad spectrum light, with greater short wavelength (blue) emissions. This switch is problematic from the perspective of increased astronomical and ecological light pollution. Short wavelength light is more likely to
328:
The G-index does not directly measure light pollution, but rather says something about the color of light coming from a lamp. For example, since the equation defining G-index is normalised to total flux, if twice as many lamps are used, the G-index would not change; it is a measure of fractional
107:
1229:
578:
389:
The problem with these approaches is that CCT is not perfectly correlated with blue light emissions. Lamps with identical CCT can have quite different fractional blue light emissions. This is because CCT is based upon comparison to a
703:
1232:, Regional Government of Andalusia (note: Spanish language page; English language handbook on index G, and LibreOffice spreadsheet in English for index computation, are linked from the lower part of the page.)
262:{\displaystyle G=-2.5\mathrm {log} _{10}{\frac {\sum \limits _{\lambda =380\mathrm {nm} }^{500\mathrm {nm} }E(\lambda )}{\sum \limits _{\lambda =380\mathrm {nm} }^{780\mathrm {nm} }E(\lambda )V(\lambda )}}}
834:
Longcore, Travis; RodrĂguez, Airam; Witherington, Blair; Penniman, Jay F.; Herf, Lorna; Herf, Michael (October 2018). "Rapid assessment of lamp spectrum to quantify ecological effects of light at night".
495:
329:
light, not total light. Similarly, the definition of G-index does not include the direction in which light shines, so it is not directly related to skyglow, which depends strongly on direction.
93:
Lamps with very different color temperatures will usually also have different G-indexes. Lamps with higher color temperatures have more blue light, and will therefore usually have lower G-index.
438:, they suggest that CCTâ€3000 K is likely to satisfy this criterion. In the stricter "comprehensive criteria", they recommend that parks and ecologically sensitive areas or areas at specified
453:. Depending on the "environmental zone", the regulation requires lighting to have a G value above 2, 1.5, or 1. In areas where astronomical activities are ongoing, it is expected that only
325:
to allow calculation of the G-index for any lamp for which the spectral power distribution is known, and it can also be calculated in the "Astrocalc" software or the f.luxometer web app.
317:), the G-index would in principle be undefined. In practice, such lamps would be reported as having G greater than some value, due to the limits of measurement precision. The
446:
astronomy observatories have a G-index greater than or equal to 2.0. Again, in this case if calculating the G-index is not possible, CCTâ€2700 K is suggested.
951:
434:
and areas considered by the procurer to be ecologically sensitive, the G-index shall be â„1.5". In the case that G-index could for some reason not be
1212:
1157:
1086:
525:
GaladĂ-EnrĂquez, D. (February 2018). "Beyond CCT: The spectral index system as a tool for the objective, quantitative characterization of lamps".
1036:
950:
Donatello, Shane; RodrĂguez
Quintero, RocĂo; Gama Caldas, Miguel; Wolf, Oliver; Van Tichelen, Paul; Van Hoof, Veronique; Geerken, Theo (2019).
1099:
466:
Research Center and the
Andalusian Regional Government (and others) to suggest or prescribe mandatory requirements based on the G-index.
1039:"Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light"
980:"Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility"
1037:
Spoelstra, K; van
Grunsven, RHA; Ramakers, JJC; Ferguson, KB; Raap, T; Donners, M, Veenendaal, EM and ME Visser (31 May 2017).
919:"ArrĂȘtĂ© du 27 dĂ©cembre 2018 relatif Ă la prĂ©vention, Ă la rĂ©duction et Ă la limitation des nuisances lumineuses | Legifrance"
1100:
Donners, M; van
Grunsven, RHA; Groenendijk, D; van Langevelde, F; Bikker JW; Longcore, T; and E Veenendaal (26 June 2018).
457:
or quasi-monochromatic lamps will be used, with G>3.5 and in principle only emissions in the interval 585-605 nm.
449:
The G-index is planned to be used by the
Regional Government of Andalusia, specifically for the purpose of protecting the
1241:
627:
359:
1235:
318:
918:
70:
743:
Kinzey, Bruce; Perrin, Tess; Miller, Naomi; Kocifaj, Miroslav; Aubé, Martin; Solano
Lamphar, HĂ©ctor (2017).
406:
for the purchase of outdoor lamps and in lighting regulations as an improved alternative to the CCT metric.
289:
58:
896:
66:
422:
704:"Why artificial light at night should be a focus for global change research in the 21st century"
98:
78:
1206:
1151:
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418:
38:
1170:
812:
Artificial Night
Lighting and Protected Lands / Ecological Effects and Management Approaches
1113:
991:
844:
781:
544:
953:
Revision of the EU Green Public
Procurement Criteria for Road Lighting and traffic signals
8:
1273:
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560:
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57:
light a lamp emits relative to its total output. It is used in order to select outdoor
655:"Physical behaviour of anthropogenic light propagation into the nocturnal environment"
309:
The sums are to be taken using a step size of 1 nm. For lamps with absolutely no
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relative to its visible emission (it is a measure of the amount of blue light per
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Aubé, Martin; Roby, Johanne; Kocifaj, Miroslav; Yamazaki, Shin (5 July 2013).
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such as high pressure sodium. The G-index was therefore developed for use in
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1023:
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Variable to quantify the short wavelength light in a visible light source
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restricts CCT to maximum 3000 K in most areas, and 2400 K or 2700 K in
347:
343:
31:
768:
Luginbuhl, Christian B.; Boley, Paul A.; Davis, Donald R. (May 2014).
744:
720:
659:
Philosophical
Transactions of the Royal Society B: Biological Sciences
1171:
Straka, TM; Greif, S; Schultz, S; Goerlitz, HR; and CC Voigt (2020).
1126:
1101:
856:
833:
450:
391:
1236:
Information on Green Public
Procurement of Street Lighting in the EU
770:"The impact of light source spectral power distribution on sky glow"
539:
439:
354:
frequently place limits on blue light emissions. For example, the "
314:
1230:
More information, including a spreadsheet for calculating G-index
431:
62:
30:
is a variable that was developed to quantify the amount of short
20:
1102:"Colors of attraction: Modeling insect flight to light behavior"
443:
371:
367:
749:(Technical report). Pacific Northwest National Lab. PNNL-26411
427:
34:
809:
Longcore, Travis; Rich, Catherine; DelBusso, Leigha (2016).
746:
An Investigation of LED Street Lighting's Impact on Sky Glow
774:
Journal of Quantitative Spectroscopy and Radiative Transfer
527:
Journal of Quantitative Spectroscopy and Radiative Transfer
46:
742:
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375:
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below 500 nm (e.g. Low Pressure Sodium or PC Amber
977:
959:(Technical report). Joint Research Centre. EUR 29631 EN
421:
incorporated the G-index into their guidelines for the
110:
808:
767:
702:Davies, Thomas W.; Smyth, Tim (10 November 2017).
604:"LICA AstroCalc - Comparador de filtros y cĂĄmaras"
493:
261:
1244:, Online calculator for g-index and other indexes
1255:
815:(Technical report). NPS/NRSS/NSNS/NRR--2016/1213
394:light source, which is a poor approximation for
524:
337:The ongoing global switch from (mainly) orange
827:
1211:: CS1 maint: multiple names: authors list (
1156:: CS1 maint: multiple names: authors list (
1085:: CS1 maint: multiple names: authors list (
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1173:"The effect of cave illumination on bats"
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97:The G-index is grounded in the system of
69:. The G-index was originally proposed by
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837:Journal of Experimental Zoology Part A
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45:). The smaller the G-index, the more
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360:International Dark-Sky Association
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358:seal of approval" program of the
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319:Regional Government of Andalusia
282:is the wavelength in nanometers;
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101:, and is defined as follows:
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1005:10.1371/journal.pone.0067798
364:correlated color temperature
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7:
1190:10.1016/j.gecco.2019.e00808
795:10.1016/j.jqsrt.2013.12.004
557:10.1016/j.jqsrt.2017.12.011
494:Junte de Andalucia (2018).
290:spectral power distribution
10:
1290:
897:"Fixture Seal of Approval"
276:G is the spectral G-index;
67:ecological light pollution
18:
461:Questionable Use Warning
423:Green Public Procurement
362:limits lights to have a
1238:, Joint Research Centre
583:www.juntadeandalucia.es
99:astronomical photometry
1055:10.1098/rspb.2017.0075
923:www.legifrance.gouv.fr
671:10.1098/rstb.2014.0117
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79:Calar Alto Observatory
708:Global Change Biology
585:(in European Spanish)
419:Joint Research Centre
416:European Commission's
400:vapor discharge lamps
370:, while the national
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71:David GaladĂ EnrĂquez
1242:f.luxometer web tool
579:"Ăndice espectral G"
339:high pressure sodium
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39:visible light source
1118:2018JEZA..329..434D
996:2013PLoSO...867798A
849:2018JEZA..329..511L
786:2014JQSRT.139...21L
549:2018JQSRT.206..399G
304:luminosity function
1248:Astrocalc software
665:(1667): 20140117.
503:(Technical report)
497:Ăndice espectral G
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721:10.1111/gcb.13927
653:(16 March 2015).
366:(CCT) below 3000
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961:. Retrieved
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292:of the lamp;
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963:12 February
928:12 February
903:12 February
819:12 February
753:12 February
533:: 399â408.
507:12 February
352:legislation
323:spreadsheet
55:ultraviolet
1274:Radiometry
1258:Categories
1183:: e00808.
633:2019-04-29
613:2019-04-01
589:2019-04-01
540:1712.06825
474:References
436:calculated
348:atmosphere
85:Definition
32:wavelength
1199:210303101
780:: 21â26.
451:night sky
440:distances
392:blackbody
333:Rationale
311:emissions
302:) is the
251:λ
239:λ
201:λ
197:∑
188:λ
150:λ
146:∑
118:−
1269:Lighting
1144:49421077
1136:29944198
1073:28566484
1049:(1855).
1024:23861808
984:PLOS ONE
883:48364989
875:29894022
730:29124824
689:25780231
651:Aube, M.
565:73564862
382:such as
1114:Bibcode
1064:5454258
1015:3702543
992:Bibcode
845:Bibcode
782:Bibcode
680:4375359
545:Bibcode
444:optical
432:gardens
356:fixture
346:in the
344:scatter
288:is the
63:skyglow
21:g-index
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372:French
272:where
51:violet
1264:Color
1195:S2CID
1140:S2CID
957:(PDF)
879:S2CID
561:S2CID
535:arXiv
501:(PDF)
442:from
428:parks
73:, an
59:lamps
53:, or
43:lumen
37:in a
35:light
1213:link
1158:link
1132:PMID
1087:link
1069:PMID
1020:PMID
965:2019
930:2019
905:2019
871:PMID
821:2019
755:2019
726:PMID
685:PMID
509:2019
426:"in
398:and
396:LEDs
65:and
47:blue
26:The
1185:doi
1122:doi
1110:329
1059:PMC
1051:doi
1047:284
1010:PMC
1000:doi
861:hdl
853:doi
841:329
790:doi
778:139
716:doi
675:PMC
667:doi
663:370
553:doi
531:206
410:Use
376:law
315:LED
220:780
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