Air quality improving in Eastern U.S.

WASHINGTON – Ozone levels are falling sharply in Eastern states where smog has been a recurring summer problem, the Environmental Protection Agency said Wednesday.

The improvement in air quality for a third of the nation’s population is due to fewer emissions of nitrogen oxides from hundreds of coal-burning power plants, manufacturing and other large facilities in 19 Eastern states.

Ozone occurs naturally in the stratosphere, where it is a shield against harmful ultraviolet rays. But ground level ozone pollution caused by nitrogen oxides reacting with other chemicals produces smog, particularly in the summer months when the sun is hottest and brightest

Other major sources of the pollution are motor vehicle exhaust, gas vapors and chemical solvents.

EPA said in an annual report that nitrogen oxides from hundreds of power plants and other industrial sources in the East fell to 530,000 tons in 2005, an 11 percent decrease from 2004, and a more than 50 percent decrease from the 1.2 million tons in 2000.

Based on air monitoring data, EPA said 66 percent of the areas that in 2004 failed to meet national air quality health standards now exceed the standards.