Production of Nox and other precursors of ozone formations in the Uinta Basin

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Journal/Book Title/Conference

AGU Fall Meeting


San Francisco, CA

Publication Date



The Uinta Basin, located in northeastern Utah, sometimes experiences ozone mixing ratios greater than the EPA NAAQS during specific meteorological conditions that include a combination of snow cover and inversion. We monitored ozone and some of its precursors, including NO, NO2, NOx (NO + NO2), and NOy (sum of reactive nitrogen species), at two sites (Roosevelt and Horse Pool). The Roosevelt site is in a city of about 6,000 people, and the Horse Pool site is in an area of intensive oil and gas production. In February and March 2012, NO, NO2, and NOy mixing ratios were 0.5 ± 0.8, 5.2 ± 2.6, and 6.5 ± 3.9 ppb at Roosevelt and 0 ± 1.3, 2.8 ± 2.7, and 4.1 ± 4.4 ppb at Horse Pool, respectively (mean ± standard deviation). NO, NO2, and NOx were measured at 7 other sites around the Basin by other entities. The spatial and temporal patterns in NOx and NOy indicate the dominance of local source influences on observed mixing ratios. NOx at urban sites and in oil and gas production areas appeared strongly influenced by traffic patterns. At some sites, wind direction analysis and air trajectory analysis indicated that areas of oil and gas production are significant sources of NOx, though pinpointing individual NOx sources proved difficult.

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