The Daily Parker

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A light story

Chicago Public Media's Curious City blog examined the city's plan to replace 270,000 sodium vapor streetlights with LEDs in the next three years:

[C]ity officials are undertaking an ambitious four-year plan to use LEDs for about 80 percent of the city’s streetlights. They hope this plan will save the cash-strapped city $100 million over a decade and improve public safety. This summer, the city will charge forward with the next phase of the plan, which will ultimately replace 270,000 lights around the city by 2021.

But critics say this isn’t a bright idea — or maybe too bright of an idea? — and they point to a growing body of science showing links between some LED lights and health and environmental problems.

Here’s a rundown of those concerns, what experts say, and how the city responded.

1. Light pollution: Will I be able to see the stars in the sky?

What’s going on? Chicago has long been one of the most light polluted cities in the world, hampering citizens’ ability to see stars, according to some scientists. Over the past year, the city has been installing a type of LED light that it says will reduce overall light pollution. Those lights clock in at 3,000 Kelvin, which is the unit used to measure light temperature with higher numbers having more blue light. But critics say those lights give off too much blue light, which can worsen light pollution, and they want the city to use LED lights that are lowered to 2,200 Kelvin with a much more orange hue.

What do the experts say? Professor Martin Aube, a Canadian physicist and light pollution researcher, says the LED lights the city is installing now could actually slightly reduce light pollution compared to the older, non-LED lights they’re replacing. But he says using 2,200-Kelvin LED lights would reduce Chicago’s light pollution by “at least 50 percent” of current levels.

Also interesting is who asked the question and how far he got on his own.

Comments (1) -

  • David Harper

    5/25/2018 1:17:54 PM +00:00 |

    The sodium-vapour streetlights in my neighbourhood were replaced with white LED lamps several years ago.  The new lamps were so blindingly bright that we had to replace the curtains in our bedroom with heavy lightproof curtains which wouldn't have been out of place during the Blitz in World War Two.  At night, I can easily read a book inside my house by the light of the new streetlamps if the curtains are open.  And since they were installed, I can no longer see the stars from my back garden.  They may be more energy-efficient, but as an astronomer, I hate them with a passion.

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