title: High winter ozone pollution from carbonyl photolysis in an oil and gas basin.
abstract: The United States is now experiencing the most rapid expansion in oil and gas production in four decades, owing in large part to implementation of new extraction technologies such as horizontal drilling combined with hydraulic fracturing. The environmental impacts of this development, from its effect on water quality to the influence of increased methane leakage on climate, have been a matter of intense debate. Air quality impacts are associated with emissions of nitrogen oxides (NOx = NO + NO2) and volatile organic compounds (VOCs), whose photochemistry leads to production of ozone, a secondary pollutant with negative health effects. Recent observations in oil- and gas-producing basins in the western United States have identified ozone mixing ratios well in excess of present air quality standards, but only during winter. Understanding winter ozone production in these regions is scientifically challenging. It occurs during cold periods of snow cover when meteorological inversions concentrate air pollutants from oil and gas activities, but when solar irradiance and absolute humidity, which are both required to initiate conventional photochemistry essential for ozone production, are at a minimum. Here, using data from a remote location in the oil and gas basin of northeastern Utah and a box model, we provide a quantitative assessment of the photochemistry that leads to these extreme winter ozone pollution events, and identify key factors that control ozone production in this unique environment. We find that ozone production occurs at lower NOx and much larger VOC concentrations than does its summertime urban counterpart, leading to carbonyl (oxygenated VOCs with a C = O moiety) photolysis as a dominant oxidant source. Extreme VOC concentrations optimize the ozone production efficiency of NOx. There is considerable potential for global growth in oil and gas extraction from shale. This analysis could help inform strategies to monitor and mitigate air quality impacts and provide broader insight into the response of winter ozone to primary pollutants.
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA [3] Department of Chemistry, University of York, York YO10 5DD, UK (P.M.E.); Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, 6020 Austria (M.G.); Department of Chemistry, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X7, Canada (C.J.Y.).
authors.forename: Peter M
authors.initials: PM
authors.lastname: Edwards
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Brown
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Roberts
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Ravan
authors.initials: R
authors.lastname: Ahmadov
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: Robert M
authors.initials: RM
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authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Joost A
authors.initials: JA
authors.lastname: deGouw
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Dubé
authors.affiliation: Department of Atmospheric Science, University of Wyoming, Larmie, Wyoming 82070, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Field
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, USA.
authors.forename: James H
authors.initials: JH
authors.lastname: Flynn
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Jessica B
authors.initials: JB
authors.lastname: Gilman
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA [3] Department of Chemistry, University of York, York YO10 5DD, UK (P.M.E.); Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, 6020 Austria (M.G.); Department of Chemistry, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X7, Canada (C.J.Y.).
authors.forename: Martin
authors.initials: M
authors.lastname: Graus
authors.affiliation: Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Detlev
authors.initials: D
authors.lastname: Helmig
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Abigail
authors.initials: A
authors.lastname: Koss
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: Andrew O
authors.initials: AO
authors.lastname: Langford
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, USA.
authors.forename: Barry L
authors.initials: BL
authors.lastname: Lefer
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Lerner
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: Air Quality Research Division, Environment Canada, Toronto, Ontario M3H 5T4, Canada.
authors.forename: Shao-Meng
authors.initials: SM
authors.lastname: Li
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: McKeen
authors.affiliation: Department of Atmospheric Science, University of Wyoming, Larmie, Wyoming 82070, USA.
authors.forename: Shane M
authors.initials: SM
authors.lastname: Murphy
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: Parrish
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Senff
authors.affiliation: Department of Atmospheric Science, University of Wyoming, Larmie, Wyoming 82070, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Soltis
authors.affiliation: Department of Oceanic and Atmospheric Sciences, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Jochen
authors.initials: J
authors.lastname: Stutz
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Colm
authors.initials: C
authors.lastname: Sweeney
authors.affiliation: Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Chelsea R
authors.initials: CR
authors.lastname: Thompson
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Trainer
authors.affiliation: Department of Oceanic and Atmospheric Sciences, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Catalina
authors.initials: C
authors.lastname: Tsai
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Veres
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Washenfelder
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Carsten
authors.initials: C
authors.lastname: Warneke
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wild
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Department of Chemistry, University of York, York YO10 5DD, UK (P.M.E.); Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, 6020 Austria (M.G.); Department of Chemistry, Memorial University of Newfoundland, St John's, Newfoundland A1B 3X7, Canada (C.J.Y.).
authors.forename: Cora J
authors.initials: CJ
authors.lastname: Young
authors.affiliation: 1] NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA [2] Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Yuan
authors.affiliation: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Zamora