Ottawa is gradually becoming home to some 58,000 LED streetlights — even as a recent health warning has some U.S. cities rethinking the energy-saving strategy.
In 2015, the city entered into a partnership with Energy Ottawa, a subsidiary of Hydro Ottawa, to convert its old sodium and metal halide lights to LEDs over a four-year period.
This summer, however, the American Medical Association issued a report warning that certain high-intensity LED lights can cause "discomfort and disability" and that brighter residential nighttime lighting is associated with poor sleep, obesity and impaired daytime functioning.
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To get the white light associated with LEDs, designers mix yellow and blue light — and that blue light can disrupt circadian rhythms in humans, according to Robert Dick, a physics professor at the University of Ottawa and a long-time dark skies advocate.
"Life has evolved on earth for four billion years with the light and dark contrast. It's literally in our DNA," Dick told CBC's Ottawa Morning Tuesday.
"And once you disrupt that light — once you add light in the nighttime — that throws off our biochemistry. There's no winners in that."
The city says its new LED lights possess a number of benefits, including lower maintenance costs and better visibility for pedestrians, cyclists and drivers.