It's a type of pollution you can only see at night, and for some its ruining the great spectacle of the night sky.
But the City of Duluth is installing new lights along the lake walk to mitigate this problem.
DyAnne Andybur, the Energy Coordinator for the City of Duluth told me, "The reason these fixtures were chose is because of safety concerns in the Lake Walk, the two locations we're going to put fixtures this summer for demonstration and for public conversation, one is in lake place park"
The other location will be near the Fitgers complex. The lights are not only for safety, but also economics.
"They're energy efficient in that they are only 50 watts of energy per lamp, compared to 133 watts that are used." said Andybur.
That's nearly a 60% reduction in electricity. But there will also be a cost savings in maintenance.
"So what happens then is we have to drill those out and then re–tap those holes, it's very time consuming to just to do simple maintenance" Said Luke Meints the Master Electrician for the City of Duluth.
With LED technology the city will be able to create a safer, cheaper, and more beautiful night sky.
Randy Larson an advocate for Dark Sky and the Owner of Meteek told me, "A million dollars in lighting bills for our general lighting. That again can be significantly reduced with LED lighting and our hope is as that is done that we are putting in dark sky responsible lighting"
There are 168 lights along Lake Walk that are being considered for replacement with these new LED and Dark Sky compliant lights.
Meteorologist Adam Lorch