Lighting in Design Q1 2023
I n a recent column for our sister publication, Sparks Electrical News , Philip Hammond from the BHA School of Lighting noted that he is deep ly conscious of the impact of over-illumination in indoor applications and even more aware of the dramatic effect of excessive outdoor lighting. “Lighting that is too bright is damaging to the en vironment in general, but particularly to the fauna and flora. My research into the adverse effects of most outdoor lighting continues. I hope to com plete it early in 2023 and write a research paper on my findings. Much has been done in the UK, Europe and the USA. In fact, I have participated in some of the research and experimental work that has been done and continues in Denmark.” I read recently that a team of researchers fromSweden and the USA is pushing to establish a common methodology for how to define light pollution and measure its astronomical, ecolog ical, and human consequences. Many studies have claimed ill effects of light at night (LAN) on stargazing, on flora and fauna, and on people’s health, but the lack of a uniform approach can make it difficult to reach universal conclusions and is hindering efforts to tackle the problems on a broad scale, note the authors of a paper published at last year’s Lux Europa 2022 conference in Prague. In all three fields (astronomical, ecological and human), a plethora of methods is used for measuring the dependent and independent var iables. The authors, led by Annika K. Jägerbrand of Halmstad University in Halmstad, Sweden, say there is a compelling need to resolve the inconsistencies, because a multitude of studies do indeed, in their own manner, illustrate the damaging effects of light at night across all three areas. For example, they point to the lose-lose proposition that light at night can sometimes make some species more vulnerable to pred ators who normally only work by day, while in other instances it can shrink feeding grounds by undermining natural habitats, as pointed out in different studies. But the methods applied in light pollution studies vary widely, thus meaningful
and actionable data is not easily attained. In another recent study, a German research group has attempted to quantify the extent to which artificial lighting has caused stars to van ish from human view. In suggesting an alarming 60% decline over 18 years, the team implicates LEDs in more ways than one. The researchers from the GFZ German Research Centre for Geosciences in Potsdam correlated star visibility with changes in sky brightness as measured by 51 351 individuals who used a template provided by Tucson, Arizona’s National Optical-Infrared Astronomy Research Laboratory, which is part of the U.S. government’s National Science Foundation. The measurements took place between January 2011 and August 2022 and revealed an annual increase of 9.6% in sky brightness. “For an 18-year period (such as the duration of a human childhood), this rate of change would increase sky brightness by more than a factor of 4,” the team states in the paper lead by Chris topher C.M. Kyba. “A location with 250 visible stars would see that number reduce to 100 visible stars over the same period.” Doing the math, that means that 60% of stars are fading from view every 18 years. The researchers note that earlier measure ments of sky brightness taken from satellites have failed to capture blue spectra that can veer skywards from LED lighting. And, they note, blue light energy is particularly guilty of washing out the view of stars. The report does not mention the increase in blue spectra detected in another recent study of similar years in Europe by Brit ain’s University of Exeter, but the two studies corroborate that blue wavelengths are night sky culprits. Even properly pointed streetlights can be culpable night-sky villains in the general sense that the energy efficiency of LEDs has encouraged their adoption, making artificial lighting more widespread than in pre-LED days. As you can see, there are a number of con cerns; however, more research is needed – and will be conducted – over the coming years. Watch this space.
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LiD Q1 - 2023
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