LOGAN — Ah, Cache Valley: snow-capped peaks, picture-book countryside, pristine air — but the valley's air isn't that pristine anymore.

The Environmental Protection Agency is on the verge of declaring the valley's air doesn't meet the standards for particulate pollution.

Using averages from 2004, 2005 and 2006, the EPA has concluded the valley's air violates clean-air standards, said Callie Videtich, an EPA official in Denver. If the averages for 2005, 2006 and 2007 don't improve significantly, the EPA will likely designate Cache Valley as a non-attainment area in December 2008, she said.

In that case, state and local officials would be required to take measures to reduce air pollution. "They'll have to put in control measures to bring the area under containment," Videtich said.

But state and local officials aren't waiting until then. The Bear River Health Department in 2004 created the Air Quality Task Force, which is working with the State Division of Air Quality to reduce the valley's pollution by encouraging people to drive less.

The task force posts electronic signs at the north and south ends of Logan's Main Street during the winter to tell drivers when air pollution reaches unhealthy levels, said Grant Koford, an environmental health scientist for the health department who heads the task force.

Other strategies include radio advertisements, informational DVDs distributed to civic and religious groups, free raffles for bus riders and contests among high schools to reduce the number of cars in lots.

"We've done everything we can think of trying to get the word out and educate everybody to what the problem is," Koford said.

Officials are also analyzing the sources of pollution and will create computer models to help determine the best control strategies, said Bryce Bird, planning branch manager for the State Division of Air Quality.

Although the levels of particulate pollution in Cache Valley aren't high enough to harm healthy people, they can cause problems for the young, the elderly and those with respiratory problems like asthma, Koford said. Recent studies indicate particulate pollution can even damage the cardiovascular system, he said.

With Cache County's population of about 100,000 expected to double by 2040, air pollution is a big concern. On Jan. 15, 2004, Cache Valley had the dirtiest air in the nation, and schoolchildren were kept indoors during lunch and recesses more than a dozen days that winter.

Last winter, pupils at Greenville Elementary School in North Logan were not allowed to go outside on five or six days, said Principal Joel Allred. He said he monitors particulate pollution hourly via computer on bad days.

When the levels hit 80 to 90 micrograms per cubic meter, Allred keeps the children indoors. He said children with respiratory problems are especially at risk.

"Kids who have asthma need to be in, period," Allred said. "Those kids do not go outside."

But he said it's not easy controlling hundreds of rambunctious youngsters indoors.

"Can you imagine 500 kids in a gym throwing balls?" he asked. "It's pandemonium."

Although many factors contribute to particulate pollution, Koford said automobiles are the main culprits. Internal-combustion engines generate ammonium nitrate, which a photochemical reaction turns into tiny nitric acid particles.

Cold air hastens the reaction, which is why particulate pollution isn't as bad where it's warm, like indoors. During the winter, an upper layer of warm air often traps a lower level of cold air between the Wellsville and Bear River mountain ranges.

The temperature inversions sometimes push the particulate level above the EPA's new threshold of 35 micrograms per cubic meter. Koford said the old standard of 65 micrograms per cubic meter was changed in December after studies showed that lower concentrations can cause health problems.

If state and local officials don't come up with a plan to reduce pollution, the EPA will impose a plan, Videtich said. Ultimately, if Cache Valley's air doesn't improve, the federal government could withhold funds for highway construction in Utah, Koford said.

So far, however, the EPA is pleased with local efforts. In October, the EPA gave the task force an environmental achievement award for its efforts to curb pollution.

"Cache County is way out front," Videtich said. "They understand that they do have significant problems."

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