ScienceDaily (Nov. 28, 2006) — Nitrogen oxides (known as NOx) emitted by fossil fuel combustion play a crucial role in producing ground level ozone, a pollutant hazardous to human health that contributes to smog over urban areas.

In 1999, coal-burning power plants represented about 25 percent of U.S. manmade NOx emissions, and recent pollution control measures by utility companies have sought to reduce NOx emissions.

Kim et al. analyzed satellite data and air quality model simulations to document regional trends in emissions. They found a declining regional trend in NOx emissions in the eastern United States. Over the Ohio River Valley, where power plants dominate NOx emissions, NOx pollution has decreased by 40 percent since 1999.

This decrease is larger than that seen in the northeast urban corridor. The researchers' model simulations predict lower ground-level ozone concentrations as a result of these NOx emission reductions. They suggest that further substantive reductions in eastern U.S. NOx levels will require decreases in mobile sources of Nox emissions, such as car exhaust.

Title: Satellite-observed US power plant NOx emission reductions and their impact on air quality

Authors: S.-W. Kim, S. A. McKeen, G. J. Frost, and E.-Y. Hsie: Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A.; also at Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, U.S.A.; A. Heckel, A. Richter, J. P. Burrows: Institute of Environmental Physics and Institute of Remote Sensing, University of Bremen, Germany; M. K. Trainer: Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A; S. E. Peckham and G. A. Grell: Global Systems Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A.; also at Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, U.S.A.

Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL027749, 2006

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