Articles | Volume 10, issue 8
Atmos. Meas. Tech., 10, 2941–2968, 2017
Atmos. Meas. Tech., 10, 2941–2968, 2017

Research article 16 Aug 2017

Research article | 16 Aug 2017

Observations of VOC emissions and photochemical products over US oil- and gas-producing regions using high-resolution H3O+ CIMS (PTR-ToF-MS)

Abigail Koss1,2,3, Bin Yuan1,2,a, Carsten Warneke1,2, Jessica B. Gilman1, Brian M. Lerner1,2,b, Patrick R. Veres1,2, Jeff Peischl1,2, Scott Eilerman1,2, Rob Wild1,2, Steven S. Brown1,3, Chelsea R. Thompson1,2, Thomas Ryerson1, Thomas Hanisco4, Glenn M. Wolfe4,5, Jason M. St. Clair4,5, Mitchell Thayer6, Frank N. Keutsch6,7, Shane Murphy8, and Joost de Gouw2,3 Abigail Koss et al.
  • 1NOAA Earth System Research Laboratory (ESRL), Chemical Sciences Division, Boulder, CO, USA
  • 2Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
  • 3Department of Chemistry and Biochemistry, University of Colorado Boulder, CO, USA
  • 4NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 5Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
  • 6University of Wisconsin Madison, Madison, WI, USA
  • 7Paulson School of Engineering and Applied Sciences and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
  • 8University of Wyoming, Laramie, WY, USA
  • anow at: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
  • bnow at: Aerodyne Research, Inc., Billerica, MA, USA

Abstract. VOCs related to oil and gas extraction operations in the United States were measured by H3O+ chemical ionization time-of-flight mass spectrometry (H3O+ ToF-CIMS/PTR-ToF-MS) from aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign in March–April 2015. This work presents an overview of major VOC species measured in nine oil- and gas-producing regions, and a more detailed analysis of H3O+ ToF-CIMS measurements in the Permian Basin within Texas and New Mexico. Mass spectra are dominated by small photochemically produced oxygenates and compounds typically found in crude oil: aromatics, cyclic alkanes, and alkanes. Mixing ratios of aromatics were frequently as high as those measured downwind of large urban areas. In the Permian, the H3O+ ToF-CIMS measured a number of underexplored or previously unreported species, including aromatic and cycloalkane oxidation products, nitrogen heterocycles including pyrrole (C4H5N) and pyrroline (C4H7N), H2S, and a diamondoid (adamantane) or unusual monoterpene. We additionally assess the specificity of a number of ion masses resulting from H3O+ ion chemistry previously reported in the literature, including several new or alternate interpretations.

Short summary
Oil and gas extraction activity can cause air quality issues through emission of reactive chemicals. VOCs related to extraction operations in the United States were measured by PTR-ToF-MS from aircraft during the SONGNEX campaign in March–April 2015. The detailed analysis in this work provides a guide to interpreting PTR-ToF measurements in oil- and gas-producing regions, and it includes fundamental observations of VOC speciation and mixing ratios.