SPOKANE — After more than two decades on a federal "dirty air" list, Spokane is breathing easier after government officials certified the city meets federal standards for carbon monoxide and other pollutants.

Only Wallula, a small community near Walla Walla, remains on Washington state's list of Clean Air Act violators. Wallula is expected to come off the "nonattainment" list later this month.

"The whole state will be in attainment by September," Tom Eaton, director of the U.S. Environmental Protection Agency's Washington state operations office, said Tuesday.

"After more than two decades of nonattainment, the EPA takes great pleasure" in certifying Spokane as a city that meets federal standards, Eaton said. "This is critically important to Spokane so you can continue to enjoy clean air while you grow."

Achieving attainment means new or expanding industry will not need to meet more stringent construction and permitting standards required in nonattainment areas, Erik Skelton, director of the Spokane County Air Pollution Control Authority, said yesterday.

Although the city has met federal Clean Air Act standards, residents will continue to be required to meet mandatory vehicle-emission standards until 2013 under current state law, Skelton said.

A major factor in reducing carbon-monoxide pollution is cleaner-burning cars, Skelton said. Fewer people are heating their homes with wood, and newer wood stoves burn cleaner, reducing emissions of tiny particles, he said.

The city has also adopted programs for controlling pollution, such as paving dirt streets, improving traffic flow and using chemical liquid deicers instead of road sand in the winter.

Wood smoke curtailment and motor vehicle emissions testing programs will continue, Skelton said.

Spokane Regional Chamber of Commerce spokesman Jeff Selle said the county air pollution authority, the Washington state Department of Ecology and local industry and business groups worked together for cleaner air.

The chamber initially fought the EPA over the nonattainment designation, but then worked with businesses and public agencies to get Spokane off the "dirty dozen" list.

Attainment "is proof to potential employers seeking to relocate to Spokane that we are a community that cares about our quality of life," Selle said.

Grant Pfeifer, Ecology's regional air quality director, said Spokane has a challenging geographic situation because the growing city is located in a "bowl" that traps pollution near the ground.

The last time Spokane's air exceeded federal carbon monoxide standards was 1996, Skelton said. The last measured violation of particulate standards occurred in 1993.

But Skelton said there are concerns that Spokane may begin violating EPA standards for ozone, another pollution caused by cars.

"We're interested in doing proactive, voluntary things to reduce ozone precursors," such as nitrogen oxides and hydrocarbons that come from car tailpipes, Skelton said. Hydrocarbons also come from refueling, painting and other sources, he said.

"From a regulatory standpoint, we will continue to keep businesses in our permit system and do regulatory inspections," he said. "The voluntary piece is to continue to encourage people to get out of cars: to take car pools, buses or other means than single-occupancy vehicles."