VERNAL — Dozens of scientists have begun the process of analyzing the mountains of data they collected in their effort to determine why the Uintah Basin experiences unhealthy concentrations of ground-level ozone during the winter.
"Trying to distill all of the information down into a set of conclusions is really difficult," Brock LeBaron, deputy director of the state Division of Air Quality, told the Deseret News.
"They're trying to put that data together to tell a story about how ozone is formed during the winter," he said.
In the past, the air in rural northeastern Utah has registered ground-level ozone during the winter at concentrations higher than those found at the height of summer in major U.S. cities like Los Angeles.
During the first three months of 2011, ground-level ozone exceeded federal standards 26 times in the Uintah Basin, according to data gathered by the U.S. Environmental Protection Agency. That was down from 37 days for the same period in 2010, the agency said.
For the winter of 2012 — one of the driest in Utah in recent years — LeBaron said the region never exceeded federal standards.
"I think the high value we saw this winter was maybe 65 parts per billion," he said. "The standard is 75 parts per billion."
Scientists believe winter ozone is produced when chemical particles from automobile exhaust and other sources is trapped under an atmospheric inversion and heated up by sunlight reflecting off the snow on the ground.
"We don't know why snow cover plays such an important part chemically," LeBaron said. "We know that without having snow cover and stable inversion conditions, we're not going to see high ozone values."
The 2011-12 Uintah Basin Winter Ozone Study — a $5.5 million project — included a number of components, not all of which were dependent on heavy snowpack for results. One of those components was identifying the "chemical fingerprint" of individual emission sources.
"What I'm hearing from these researchers in the last couple days is that this has really gone on better under the clean conditions than it would have if you'd had circulation of a lot of dirty air under the inversion," LeBaron said. "That would kind of cloud that fingerprint."
The EPA is a partner in the study, as are a number of federal, state, tribal and county entities, including the U.S. Forest Service, the National Park Service, the Bureau of Land Management, the National Oceanic and Atmospheric Administration, the Utah Department of Environmental Quality, the State School and Institutional Trust Lands Administration, the Ute Indian Tribe, Duchesne and Uintah counties, and the Uintah County Impact Mitigation Special Service District.
Scientists took measurements at 30 fixed monitoring stations around the region. They also used a van loaded with sophisticated equipment capable of measuring air quality while moving, as well as tethered balloons that could be raised more than 525 feet in the air to take samples.
Researchers also sought to catalog all emission sources in the region that might contribute to the formation of winter ozone, LeBaron said.
"Ozone isn't emitted directly," he said. "It's created in the atmosphere from (volatile organic compounds) and oxides of nitrogen."
The exploration for and production of oil and natural gas in the region is one of the largest suspected emission sources. Traditional processes are known to give off large amounts of ozone precursors.
But Paul Hacking, director of the Uintah Impact Mitigation District, noted that the recently completed study showed that "some of the lower (ozone) numbers were in the oil and gas fields."
"So something is happening here that causes this," he said. "That's what the scientists are trying find out: What is actually occuring that creates these levels? What are the emission sources, and what are the way we can mitigate some of those sources?"
The energy industry is the largest economic driver in the Uintah Basin, accounting for thousands of direct and indirect jobs, and millions of dollars in tax revenues to the counties and the state.
"We are concerned about jobs in our area," Hacking said. "We are concerned about our health as well. We think we can have both, if we find responsible solutions to these problems."
Researchers are expected to release some preliminary findings from the 2011-12 study and suggested mitigation protocols within the next month, LeBaron said. The final report isn't expected to be finished until October.
As for the portions of the study that required more snowfall than the Uintah Basin received this past winter, LeBaron said scientists will have to "come back and fill in those holes in the future when the conditions are right."
"Now that we have all the infrastructure set up, we'll be forecasting the conditions and we'll be deploying in a rapid fashion to get the last remaining pieces that we need," he said.