Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility

Abstract

Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED) and LED 2700 K lamps filtered with the new Ledtech’s Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.

Melatonin – metabolism and the role of pineal hormone

“…Natężenie oświetlenia jest dodatnio skorelowane z supresją produkcji melatoniny. 15 Kolejnym istotnym czynnikiem zaburzającym cykl okołodobowy, a tym samym wpływającym na wydzielanie melatoniny, jest praca zmianowa, szczególnie w porze nocnej. 16 Zaburzenie cyklu syntezy melatoniny na przestrzeni doby uwidacznia rozregulowanie tzw.…”

“…42 Badania dostarczają coraz więcej dowodów na współwystępowanie rozchwiania równowagi melatoninowej ustroju oraz cyklu okołodobowego z wieloma chorobami -nowotworem piersi, otyłością, zaburzeniami wydzielania insuliny i tolerancji glukozy, a także zespołem metabolicznym. 15,[25][26][27][28] Piśmiennictwo…”

Artificial light-at-night – a novel lifestyle risk factor for metabolic disorder and cancer morbidity

“…The spectral sensitivity of MLT synthesis suppression demonstrates wavelength-dependent sensitivity with robust effects in response to short wavelength (450-500 nm) exposure [44,45]. Accordingly, a comprehensive study on the effect of various artificial lights on MLT suppression revealed that 4000 K and 5000 K LED lights were the most effective in the suppression of the hormone compared with counterpart technologies, such as incandescent, halogen, and florescent lightening systems [46]. Furthermore, a different study demonstrated an inverse association between MLT synthesis and the irradiances of narrowband blue LED exposure (peak λ = 469 nm; ½ peak bandwidth = 26 nm), and the impact of this spectrum was evidently larger than that of 4000 K of white florescent at twice the energy of the former [44,47].…”

Unified framework to evaluate non-visual spectral effectiveness of light for human health

“…the circadian and the photopic system, can be useful for comparing spectral power distributions (SPDs) of different light sources. 15,16,[40][41][42] These ratios provide estimates of the relative errors that would be generated if a conventional light measuring device employing the V(λ) function were used to characterize input to the circadian system. 40 Gall and Bieske 15 introduced the circadian action factor to make it easy to transfer the absolute quantities to each other.…”