Piecing together the Uintah Basin ozone puzzle
Oil and gas production is partly to blame for high levels of ozone in the Uintah Basin, a team of researchers has found. Photo courtesy Samuel Oltmans.
By Clint Talbott
High ozone levels in the lower atmosphere are a respiratory health hazard, but the pollutant generally spikes in summer in cities. In the winter hinterlands, ground-level ozone has been a non-issue.
But in recent years, scientists observed significant ozone-level spikes during winter in Utah’s rural Uintah Basin. Wintertime ozone levels in 2011 rose as much as three times higher than Manhattan’s levels in summertime, when sunlight catalyzes some forms of air pollution into ozone.
Utah’s rural, winter ozone spike was a mystery—not so much a 'whodunit as a 'whatdunit,' The Salt Lake Tribune observed.Ground-level ozone—a highly reactive gas composed of three oxygen atoms—can worsen bronchitis, emphysema and asthma. Prolonged exposure may permanently scar lung tissue.
Utah’s rural, winter ozone spike was a mystery—not so much a “whodunit” as a “whatdunit,” The Salt Lake Tribune observed.
The culprits include snow, still air, temperature inversions and high emissions of methane and other reactive gases from the 10,000 oil and gas wells in the basin, a large collaboration of researchers has found.
The scientific sleuths came from the University of Colorado Boulder and a host of federal, state and local agencies.
Samuel Oltmans, a research associate at CU-Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES), was part of a large team that measured Uintah Basin air quality in 2013, when ozone levels were “extraordinary.” He and others summarized their findings at this year’s annual meeting of the American Meteorological Society, held in Atlanta.
In contrast to 2011, the winter ozone levels in 2012 were “pretty typical” for the Uintah Basin, hovering around 40 parts per billion, well below the EPA’s National Ambient Air Quality Standard of 75 ppb.
In 2013, however, values again spiked as high as 140 ppb. On about 20 days between Jan. 1 and the middle of March 2013, researchers observed eight-hour average values of more than 100 ppb. During the same period, 40 days exceeded the 75 ppb standard.
One difference between 2013 and 2012, when ozone levels were significantly lower, was snow. In 2012, there was no snow on the ground. “In 2013, the ground was covered with snow during the entire period from late December to early March,” Oltmans said.
Snow on the ground coincides with temperature inversions, which trap pollutants. In the Uintah Basin, researchers observed a shallow inversion layer of about 200 meters above the ground’s surface.
Snow has a high albedo (or reflectivity of solar energy). Snow reflecting sunlight nearly doubles the ultraviolet radiation available for atmospheric photochemistry.
The Uintah Basin is a nearly enclosed bowl, “so there isn’t a lot of flushing of air if you have stagnant conditions,” Oltmans said.
“You also have very large, industrial-sized oil-and-gas exploration and extraction activities going on, with a large number of oil and gas wells, as well as large gas-processing facilities.”
Gas fields emit volatile organic compounds (VOCs) and reactive nitrogen oxides—or NOx—which are precursors to ozone.
The CIRES researchers took air samples from a low-flying airplane between Jan. 31 and Feb. 5, 2013. During that period, ozone levels grew steadily, Oltmans said.
Methane levels also rose during that testing period, and the gas spread over the basin.
Background levels of methane in the Uintah Basin are generally less than 2 parts per million. Above the gas fields, on Jan. 31, 2013, methane levels were 8 ppm.
On Feb. 2, 2013, carbon monoxide and nitrogen dioxide levels were also high, “probably associated with the gas-processing facilities near the gas fields.”
High ozone levels corresponded with high methane levels, Oltmans noted.
While the scientists flew around the basin collecting air samples from the inversion layer, they also collected “vertical profiles” (from ground level up more than 1,000 feet) of atmospheric ozone, methane, NOx and other gases. When ozone and methane levels were at their highest levels in the inversion layer, close to the ground, they were closer to normal at higher altitudes.
The way to deal with this is collaboratively, multi-jurisdictionally. We need everyone at the table: the feds, the states, the tribal governments. We all contribute. We’re all affected by it, and we’re not going to solve it unless we come together to solve it.”Now, “We have unparalleled data for understanding both the horizontal and vertical building of wintertime high-ozone events,” Oltmans said.
Russell Schnell, a scientist at the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder, was part of Oltmans’ research group.
Schnell noted data from 2009 and 2010 showing correlation between snow on the ground in Uintah Basin and high levels of atmospheric ozone. Within a few days of a blanket of snow there, NOx can climb from 5 ppb to 50, a factor of 10, in a day, “which is pretty dramatic.”
Ozone levels climb, too, Schnell noted. But the day the snow melts, ozone and NOx levels fall just as precipitously.
When the snow comes, other factors contribute to the ozone buildup, he said. Wind speeds drop markedly while snow is on the ground, and temperature inversions, which trap a layer of colder (heavier) air beneath warmer (lighter) air, are more common.
When the snow melts, winds pick up, “and that point is when the ozone goes away,” Schnell said.
Like Oltmans, Schnell noted that high levels of ozone in winter 2013 corresponded with snow cover, stagnant air, a persistent temperature inversion and high levels of oil and gas field emissions.
In such conditions, Schnell said, “You can produce up to 60 ppb of ozone in less than four hours. That’s pretty amazing.”
In addition to the 10,000 oil and gas wells now in the basin, there are permits for some 20,000 more.
CIRES and NOAA scientists have previously observed high levels of methane emissions in the Uintah Basin, apparently stemming from leaking wells. In 2012, they measured methane leakage rates of up to 9 percent there.
Besides being an ozone precursor, methane is a powerful greenhouse gas.
A multi-agency report on the Uintah Basin’s air-quality problems noted the economic value of the oil and gas industry there. Echoing one suggestion of the report, Oltmans said:
“The only possible way for solving this problem under the conditions we had in the winter of 2013 is to control the emissions. It seems like a Herculean job. But the Uintah Basin has been relatively unregulated compared to some of the other gas fields, so there’s a lot of room for improvement of emissions. But it would take a while, because most of the controls are on new extraction.”
Oltmans also measured surprisingly high levels of the air toxin benzene, he reported at the 2013 fall meeting of the American Geophysical Union.
In the Uintah Basin study, Oltmans’ CIRES collaborators included Anna Karion, Colm Sweeney, Gaby Petron, Emrys Hall, Patrick Cullis, Allen Jordan, Chance Sterling, Sonja Wolter, Don Neff, Ben Miller and Thomas Mefford. CIRES is a joint institute of NOAA and CU-Boulder.
Also participating in the project were scientists from CU’s Institute for Arctic and Alpine Research (INSTAAR).
The INSTAAR group, led by Associate Research Professor Detlev Helmig, found that total annual VOC emissions from the Uintah Basin were roughly equivalent to annual VOC emissions from 100 million automobiles.
In 2011, the most recent year for which data are available, there were about 192 million registered “light vehicles” in the nation, the U.S. Department of Transportation reports.
The collaborating agencies studying the Uintah Basin included the U.S. Bureau of Land Management, EPA, Utah Department of Environmental Quality, the Uintah Impact Mitigation Special Service and the Western Energy Alliance.
The team included researchers from Utah State University, the University of Wyoming and the University of Washington.
In an interview on Utah Public Radio, Leonard Herr, the BLM’s air-resource specialist in Utah, explained why the research effort is so large:
“The way to deal with this is collaboratively, multi-jurisdictionally. We need everyone at the table: the feds, the states, the tribal governments. We all contribute. We’re all affected by it, and we’re not going to solve it unless we come together to solve it.”
Clint Talbott is director of communications and external relations for the College of Arts and Sciences and editor of the Colorado Arts and Sciences Magazine.
June 24, 2014
Federal, state and local agencies team up with researchers from CU-Boulder and other universities to study wintertime ozone in oil-, gas-producing basin
By Clint Talbott
High ozone levels in the lower atmosphere are a respiratory health hazard, but the pollutant generally spikes in summer in cities. In the winter hinterlands, ground-level ozone has been a non-issue.
But in recent years, scientists observed significant ozone-level spikes during winter in Utah’s rural Uintah Basin. Wintertime ozone levels in 2011 rose as much as three times higher than Manhattan’s levels in summertime, when sunlight catalyzes some forms of air pollution into ozone.
Utah’s rural, winter ozone spike was a mystery—not so much a 'whodunit as a 'whatdunit,' The Salt Lake Tribune observed.Ground-level ozone—a highly reactive gas composed of three oxygen atoms—can worsen bronchitis, emphysema and asthma. Prolonged exposure may permanently scar lung tissue.
Utah’s rural, winter ozone spike was a mystery—not so much a “whodunit” as a “whatdunit,” The Salt Lake Tribune observed.
The culprits include snow, still air, temperature inversions and high emissions of methane and other reactive gases from the 10,000 oil and gas wells in the basin, a large collaboration of researchers has found.
The scientific sleuths came from the University of Colorado Boulder and a host of federal, state and local agencies.
Samuel Oltmans
Samuel Oltmans, a research associate at CU-Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES), was part of a large team that measured Uintah Basin air quality in 2013, when ozone levels were “extraordinary.” He and others summarized their findings at this year’s annual meeting of the American Meteorological Society, held in Atlanta.
In contrast to 2011, the winter ozone levels in 2012 were “pretty typical” for the Uintah Basin, hovering around 40 parts per billion, well below the EPA’s National Ambient Air Quality Standard of 75 ppb.
In 2013, however, values again spiked as high as 140 ppb. On about 20 days between Jan. 1 and the middle of March 2013, researchers observed eight-hour average values of more than 100 ppb. During the same period, 40 days exceeded the 75 ppb standard.
One difference between 2013 and 2012, when ozone levels were significantly lower, was snow. In 2012, there was no snow on the ground. “In 2013, the ground was covered with snow during the entire period from late December to early March,” Oltmans said.
Snow on the ground coincides with temperature inversions, which trap pollutants. In the Uintah Basin, researchers observed a shallow inversion layer of about 200 meters above the ground’s surface.
Snow has a high albedo (or reflectivity of solar energy). Snow reflecting sunlight nearly doubles the ultraviolet radiation available for atmospheric photochemistry.
The Uintah Basin's bowl-like topography is conducive to temperature inversions, which trap colder (heavier) air close to the ground.
The Uintah Basin is a nearly enclosed bowl, “so there isn’t a lot of flushing of air if you have stagnant conditions,” Oltmans said.
“You also have very large, industrial-sized oil-and-gas exploration and extraction activities going on, with a large number of oil and gas wells, as well as large gas-processing facilities.”
Gas fields emit volatile organic compounds (VOCs) and reactive nitrogen oxides—or NOx—which are precursors to ozone.
The CIRES researchers took air samples from a low-flying airplane between Jan. 31 and Feb. 5, 2013. During that period, ozone levels grew steadily, Oltmans said.
Methane levels also rose during that testing period, and the gas spread over the basin.
Background levels of methane in the Uintah Basin are generally less than 2 parts per million. Above the gas fields, on Jan. 31, 2013, methane levels were 8 ppm.
On Feb. 2, 2013, carbon monoxide and nitrogen dioxide levels were also high, “probably associated with the gas-processing facilities near the gas fields.”
High ozone levels corresponded with high methane levels, Oltmans noted.
While the scientists flew around the basin collecting air samples from the inversion layer, they also collected “vertical profiles” (from ground level up more than 1,000 feet) of atmospheric ozone, methane, NOx and other gases. When ozone and methane levels were at their highest levels in the inversion layer, close to the ground, they were closer to normal at higher altitudes.
The way to deal with this is collaboratively, multi-jurisdictionally. We need everyone at the table: the feds, the states, the tribal governments. We all contribute. We’re all affected by it, and we’re not going to solve it unless we come together to solve it.”Now, “We have unparalleled data for understanding both the horizontal and vertical building of wintertime high-ozone events,” Oltmans said.
Russell Schnell, a scientist at the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder, was part of Oltmans’ research group.
Schnell noted data from 2009 and 2010 showing correlation between snow on the ground in Uintah Basin and high levels of atmospheric ozone. Within a few days of a blanket of snow there, NOx can climb from 5 ppb to 50, a factor of 10, in a day, “which is pretty dramatic.”
Ozone levels climb, too, Schnell noted. But the day the snow melts, ozone and NOx levels fall just as precipitously.
When the snow comes, other factors contribute to the ozone buildup, he said. Wind speeds drop markedly while snow is on the ground, and temperature inversions, which trap a layer of colder (heavier) air beneath warmer (lighter) air, are more common.
When the snow melts, winds pick up, “and that point is when the ozone goes away,” Schnell said.
Ozone levels in the Uintah Basin changed dramatically from 2012 to 2013. Researchers' task was to determine why. Image courtesy of Samuel Oltmans.
Like Oltmans, Schnell noted that high levels of ozone in winter 2013 corresponded with snow cover, stagnant air, a persistent temperature inversion and high levels of oil and gas field emissions.
In such conditions, Schnell said, “You can produce up to 60 ppb of ozone in less than four hours. That’s pretty amazing.”
In addition to the 10,000 oil and gas wells now in the basin, there are permits for some 20,000 more.
CIRES and NOAA scientists have previously observed high levels of methane emissions in the Uintah Basin, apparently stemming from leaking wells. In 2012, they measured methane leakage rates of up to 9 percent there.
Besides being an ozone precursor, methane is a powerful greenhouse gas.
A multi-agency report on the Uintah Basin’s air-quality problems noted the economic value of the oil and gas industry there. Echoing one suggestion of the report, Oltmans said:
“The only possible way for solving this problem under the conditions we had in the winter of 2013 is to control the emissions. It seems like a Herculean job. But the Uintah Basin has been relatively unregulated compared to some of the other gas fields, so there’s a lot of room for improvement of emissions. But it would take a while, because most of the controls are on new extraction.”
Oltmans also measured surprisingly high levels of the air toxin benzene, he reported at the 2013 fall meeting of the American Geophysical Union.
In the Uintah Basin study, Oltmans’ CIRES collaborators included Anna Karion, Colm Sweeney, Gaby Petron, Emrys Hall, Patrick Cullis, Allen Jordan, Chance Sterling, Sonja Wolter, Don Neff, Ben Miller and Thomas Mefford. CIRES is a joint institute of NOAA and CU-Boulder.
Also participating in the project were scientists from CU’s Institute for Arctic and Alpine Research (INSTAAR).
The INSTAAR group, led by Associate Research Professor Detlev Helmig, found that total annual VOC emissions from the Uintah Basin were roughly equivalent to annual VOC emissions from 100 million automobiles.
In 2011, the most recent year for which data are available, there were about 192 million registered “light vehicles” in the nation, the U.S. Department of Transportation reports.
A gas plant in Uintah Basin lights up the night sky in the Uintah Basin. Photo courtesy of Samuel Olmans.
The collaborating agencies studying the Uintah Basin included the U.S. Bureau of Land Management, EPA, Utah Department of Environmental Quality, the Uintah Impact Mitigation Special Service and the Western Energy Alliance.
The team included researchers from Utah State University, the University of Wyoming and the University of Washington.
In an interview on Utah Public Radio, Leonard Herr, the BLM’s air-resource specialist in Utah, explained why the research effort is so large:
“The way to deal with this is collaboratively, multi-jurisdictionally. We need everyone at the table: the feds, the states, the tribal governments. We all contribute. We’re all affected by it, and we’re not going to solve it unless we come together to solve it.”
Clint Talbott is director of communications and external relations for the College of Arts and Sciences and editor of the Colorado Arts and Sciences Magazine.
June 24, 2014