Blackout demonstrates impact of electricity generation on clean air.

[NNadir]

"(AP) Last summer's blackout did have one bright side to it — cleaner skies that downwind from the Midwestern power plants that were idled, researchers say.

Aircraft sampling in the 24 hours following the blackout found a 90 percent drop in sulfur dioxide and a 50 percent cut in ozone levels, while visibility increased by more than 25 miles, University of Maryland researchers report..."

...On Aug. 15, the researchers realized the blackout the night before provided a rare opportunity — to compare pollution in an area downwind of idled power plants with pollution downwind of unaffected plants.

They took air samples over central Pennsylvania — in the path of air blowing in from the blacked-out region — and compared them with air samples they had taken that day over Virginia and western Maryland.

They found sulfur dioxide levels measured over Pennsylvania were 90 percent lower and ozone levels were 50 percent lower..."

http://www.cbsnews.com/stories/2004/06/11/tech/main622607.shtml