LED bulbs are causing light pollution in cities, or so it seems. The bulbs last longer, make that a lot longer than incandescent bulbs, and use less electricity so lower electric bills. So what’s not to like? Turns out that when cities replace all their high pressure sodium lights with LEDs, there are unintended consequences:
Cities around the world have been replacing energy-guzzling streetlights with brighter and whiter energy-saving LEDs. In fact, New York City is retrofitting all of its 250,000 street lights with LEDs in what the city is calling the biggest project of its type in the country.
But energy savings does not necessarily translate to happy city dwellers. In a piece in The New York Times, Brooklyn residents complained about the glaring white light creeping into their homes and eyes, causing many restless nights.
LEDs worsen light pollution by giving off more blue and green light than the high-pressure sodium lights they normally replace. And this artificial light pollution washes out the night sky and is linked to many negative consequences. Disrupted night and day cycles can confuse nocturnal animals and alter their hunting interactions, migratory patterns, and internal physiology.
It can also mess with our internal clocks. We produce melatonin at night to help us sleep, which is regulated by light and dark cycles. If we’re exposed to light at night, this can suppress melatonin levels, leading to sleep disorders or other problems such as headaches, anxiety, and obesity.
Obesity? Really? Sounds like a convenient excuse. I take a melatonin supplement every night before going to bed and I sleep well. How about window blinds in the bedroom?
Satellite photos and photos from space do show the increased intensity that results when cities switch to LED bulbs in street lighting.
[click a photo to enlarge it to full size, use the back button to return here]:
This is photo of Milan at night in 2012:
And here is Milan at night in 2015 after all street lighting was with LED bulbs:
I’m not sure a photo from space is an accurate showing of what this looks like on the ground. The photos show light that is emitted upward from lights that sit atop a 30-40 foot pole, and it does not necessarily mean that much more light directed downwards where people live. Not all LEDs are the same, they are available in color temperatures ranging from about 2800 Kelvin (warm reddish light such as the sun early in the morning or late in the afternoon) up to 5000 Kelvin (cool blueish sunlight at noon). Some of the LEDs I’ve installed on the outside of the house are brighter that the incandescents they replaced, some are dimmer. Improvements in the technology of LED bulbs will no doubt continue.
The best thing about them is that you are not constantly replacing them. The last a long time.
Bright light, big city, gone to my baby’s head
Whoa, bright light, an’big city, gone to my baby’s head
I tried to tell the woman, but she don’t believe a word I said
It’s all right, pretty baby, (gonna) need my help someday
Whoa, it’s all right, pretty baby, gonna need my help someday
Ya’ gonna wish you had a-listened, to some a-those things I said.
—- Jimmy Reed, Bright Lights, Big City
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