Smog-creating nitrogen drops in eastern U.S.
Daily satellite data show decreases in emissions of nitrogen oxides from power plants over a 7-year period.
Pollution controls on power plants appear to be working, at least with regard to emissions of nitrogen oxides (NOx) in the Ohio River valley.
Emissions from electrical power plant combustion contributed about a quarter of NOx in the U.S. in 1999. From then until the end of 2005, satellites show that those emissions dropped, researchers report in the November 29 Geophysical Research Letters.
Summer NOx levels have decreased across the eastern U.S. Over the Ohio River valley, where power plants dominate emissions, NOx has decreased by 40% since 1999. Urban areas of the U.S. Northeast saw smaller declines.
The team's model predicts lower ground-level ozone concentrations as a result of NOx reductions. The authors write that further reductions in eastern U.S. NOx levels will require decreases in mobile NOx sources, such as car exhaust.
