Why America’s Street Lights Are Turning Purple

“The 2010s saw the first big push by local, state, and federal governments to switch out the old lamps for LED streetlights, which are a lot more efficient. They also produce a much harsher, colder, blueish white light that a lot of people can’t stand. So why are they turning purple now? The thing is, white LEDs don’t exist. To make one, manufacturers use a blue LED that shines through a special filter that turns it into white(ish) light.”
“And it turns out that in the mad rush to convert everything to LEDs, no one realized that the filter layer would break down a lot quicker than anyone expected, which causes the lights to turn purple. Or blue, depending on how complete the failure is.”