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EPA says Pinal air quality meets standard for soot; more work needed

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WASHINGTON – The Environmental Protection Agency said Friday that air-quality in western Pinal County has improved enough to meet a federal standard for soot and other particles.

The notice, posted in Friday’s Federal Register, means that the state will no longer have to file air-quality improvement plans for the region around Maricopa City.

But while they welcomed the news, state and federal officials cautioned that there are other air-quality standards that have to be met in the region.

“This is good news for Pinal County,” said Eric Massey, the air quality division director for the Arizona Department of Environmental Quality, in an e-mail. “The air is significantly cleaner than it was just a few short years ago.”

The EPA proposed the change after determining that air-quality readings from a monitor in an area called Cowtown met 24-hour PM2.5 standards, which relate to fine particles that are 2.5 microns in diameter or less.

EPA rules limit those particles to 35 micrograms per cubic meter. Anything above that is considered unhealthy. But a three-year average of readings from 2010-2012 showed that the Cowtown monitor averaged 28 micrograms per cubic meter.

The proposed action means the EPA will “suspend certain federal requirements” for reporting. But it does not free state or county officials from meeting other “health based” air-quality standards, said Sandy Bahr, the director of the Grand Canyon chapter of the Sierra Club.

“We want everyone to have clean air,” she said. “There’s still alot of work to do.”

That sentiment was echoed by the director of Pinal County’s Air Quality Control District.

“This is a step in the right direction,” said Don Gabrielson, the director. “But it doesn’t relieve us of obligations to implement additional measures.”

Friday’s announcement only applies to planning and monitoring of small air particles (or soot) but not to larger, PM10, particles, said state officials.

The Cowtown monitor still reports some of the highest PM10 levels in the state, according to officials, who have noted in the past that the monitor in question is located in a relatively dusty area near a cattle feedlot and a grain mill.

“As a practical matter, the mix of sources are still contributing to the PM10″ levels, Gabrielson said.

The announcement “relieves the state of a resource burden,” said Colleen McKaughan, the associate director of air division for the EPA’s Region 9 office, which covers Arizona. But she noted that it is only pending at this point, and still subject to a 30-day public comment period.

Even if the proposal wins approval, state officials said they will continue to keep an eye on things.

“While there may be no federal requirement to conduct this air pollution improvement planning, (Arizona) may still address it in future actions,” Massey said.