Mountain States

NOAA Study: Weather Still Key Factor in Ozone Production in Uinta Basin

Last week, a study was published in Nature, examining the phenomenon of “winter ozone” in the Uinta Basin of northeastern Utah. Scientists from the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) and several other institutions conducted this research. Input was also provided by the Western Energy Alliance, an industry trade association, which supported this research to help advance the scientific understanding of the winter ozone phenomenon.

In most areas of the country, ozone is produced primarily during the summer months, as the energy from intense sunlight causes the complex photochemical reaction that creates ozone pollution. As was shown in a related study published last year, the levels of volatile organic compounds (VOCs) in the Uinta Basin can he high enough to trigger these chemical reactions even during the winter, but only in certain weather conditions.

Specifically, what the NOAA studies have found is that the amount of snow cover – which reflects sunlight — is a necessary condition for the development of winter ozone, and that sufficient snow cover sometimes exists in the Uinta Basin region. As NOAA ESRL’s James Roberts noted:

“We encountered a range of conditions during the three winters, from snowy in 2013 and 2014, to virtually no snow in 2012. Oil and gas emissions of VOCs were high in all three years, but high ozone occurred only in the cold, snowy stagnant periods.” 

For example, during the winter of 2009-2010, there were 94 days with snow depth exceeding 50mm, and there were 81 such days in 2010-2011. There were no days during the 2011-2012 winter with this much snowfall. As last year’s study stated explicitly: “Snow cover is a necessary condition for formation of winter ozone episodes.”

As reported in the Boulder Daily Camera:

Researchers found that the warmer air above can trap the colder air below, creating an inversion that concentrates the emissions for several days, allowing the hydrocarbons to “cook,” as the researchers put it, with the presence of snow on the ground accelerating the production of ozone…

Will Allison, director of the Air Pollution Control Division of the Colorado Department of Public Health and Environment, said it’s hard to say how “transferrable” the study’s findings might be.

“Every geological basin is unique, and the Uintah Basin truly is a large bowl that tends to trap air, and air can get stagnant there and not move too much,” Allison said.

The danger, of course, is that the mere presence of oil and gas activity could lead anti-industry activists to use winter ozone as justification for new regulations that kill jobs and restrict economic activity, even while not effectively addressing the problem.

Headlines about last year’s study tended toward the “blame industry first” approach, even though the conclusions were the same as this year’s study.

To be clear: oil and gas is a major industry in the Uinta Basin, and VOC emissions – when combined with specific weather conditions – interact chemically to create ozone. The industry constantly works to reduce the environmental impact of its operations – including the release of VOCs – which is why it contributed input to this research.

Armed with these new data, and with more research sure to follow, industry, state regulators and the EPA can work to find effective ways to reduce VOC emissions, and to find other ways to minimize winter ozone when snowfall is sufficient to trigger it.

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