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.
EPA Administrator Stephen Johnson called the improvement exciting. “The solutions don’t happen overnight,” he told The Associated Press in an interview. “It really does take a long-term strategy.”
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.
Johnson called the cuts a “significant achievement” from an EPA program started by President Clinton and expanded under President Bush.
The program sets overall caps on allowable levels of pollution, then lets companies trade among themselves rights to pollute up to that level. The concept is that a market in pollution permits at some point will make it cheaper for a company to install new pollution controls than keep spending money on the permits.
“What we’re seeing is that for those large facilities that are the most problematic, they’re the first ones that are installing the new pollution control equipment,” Johnson said.
The Clinton administration in 1998 ordered a clean-up of ground-level ozone pollution in the 19 states plus the District of Columbia. The states it covered are Alabama, Connecticut, Delaware, Illinois, Indiana, Kentucky, Massachusetts, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia and West Virginia.
Johnson said further improvements should result from a new program the agency announced last year, affecting states in the East, South and Midwest that are the source of pollutants causing smog downwind.
John Walke, clean air director for the Natural Resources Defense Council, an environmental advocacy group, complained that those regulations give utilities “a huge break” by allowing them to take until the 2020s to fully comply with all of the ordered pollution reductions.