Where’s the fresh air?
Ozone levels can still soar in rural areas
By Jane Palmer
Wyoming’s Green River winds its way through the Basin against the backdrop of the sharp-edged Wind River Mountains. A tranquil scene exemplifying a pristine rural environment: clean water, clean land and clean air.
Or maybe not.
When a nearby oil company left on its air-monitoring instruments one recent winter, they were in for a real surprise: Their instruments recorded levels of ozone typically seen in only urban environments. “In a rural area, especially in the wintertime, you would never see ozone like this,” said CIRES graduate student and ESRL-CIRES Fellowship recipient Ryan Neely. “People would just think it was an instrument error.”
Further checks by the Environmental Protection Agency (EPA) confirmed the readings weren’t due to faulty diagnostics. Puzzled as to the origins of these high levels of ozone, the EPA passed the mystery on to CIRES scientists.
“We basically went in to discover: What is causing this elevated ozone? Is this a weather-driven event, or is this an emissions-driven event?” said Neely, who collaborated with NOAA researchers Russell Schnell and Samuel Oltmans.
The Science
An unusual combination of raw ingredients, weather and geology produces levels of ozone typically seen only in urban environments.
The scientists found the nearby Jonah-Pinedale Anticline natural gas field churned out high levels of all the ingredients necessary to make ozone. But these ozone levels only soared under a unique set of conditions. When a high-pressure weather system moves into the snow-covered region, bringing with it cold temperatures, low wind speeds and clear skies, it creates a shallow temperature inversion, trapping high concentrations of the chemical precursors to ozone. “It basically turns the region into this big fishbowl,” he said. “Then the air just sits there and cooks, and the levels of ozone just rise and rise and rise.”
While the Green River Basin isn’t home to the hundreds of thousands of people found in a typical city, the consequences of high ozone levels are no less severe. “There are still a significant number of people and livestock out there,” Neely said.
The observation of high ozone levels in Wyoming’s rural environment is
not an anomaly, Neely said. “This would happen wherever you have a similar snow-covered Basin, a source of ozone-forming ingredients and the right type of weather systems,” he said.
Since the original discovery in Wyoming, the team has observed a similar phenomenon in Utah’s Unita Basin. A high mountain range encircles the Basin, which houses both oil and gas extraction wells. Once snow covers the ground in the winter months, the conditions ideal for creating ozone in this Basin perpetuate until the spring thaw, Neely said.
Both the scientists and the oil companies are interested in understanding just how and why ozone can soar in rural areas, Neely said. Oil companies, in particular, want to know how to mitigate air pollution and avoid severe regulations, he said.
“When they have to shut down sites, everybody loses—the taxpayers because they don’t get their revenue and the oil companies because they lose millions of dollars,” Neely said. “Everybody is interested in understanding the science.”
