Clear Skies – Blackout clears the air

The power blackout that hit eastern North America last summer may have made it darker at night, but during the day it increased visibility by up to 40 kilometres. US researchers have found that air pollution plummeted far more than they would have expected as the power plants shut down.

The concentration of ozone was halved while sulphur dioxide levels fell by 90%, clearing the haze that usually sits over Pennsylvania. “We expected to see some decreases,” says Russell Dickerson of the University of Maryland in College Park, reduction was bigger than we expected.”

This is really illuminating (no pun intended…). Back when I was an active backyard astronomer in the 80s, I really did notice the progressive degradation of visibility every year, due to haziness, but mostly due to creeping light pollution as the surrounding areas became more and more developed. It amazes me how much the atmosphere was affected by what seems to be a comparatively small event – increasing visibility by 40 kilometres and cutting ozone and SO₂ by 50% and 90% respectively is an enormous change. Amazing to think what finding a way to permanently cut those emissions out of power generation could do…

Link via Meyerweb.