Atmospheric Measurement Techniques (Aug 2017)

Observations of VOC emissions and photochemical products over US oil- and gas-producing regions using high-resolution H<sub>3</sub>O<sup>+</sup> CIMS (PTR-ToF-MS)

  • A. Koss,
  • A. Koss,
  • A. Koss,
  • B. Yuan,
  • B. Yuan,
  • B. Yuan,
  • C. Warneke,
  • C. Warneke,
  • J. B. Gilman,
  • B. M. Lerner,
  • B. M. Lerner,
  • B. M. Lerner,
  • P. R. Veres,
  • P. R. Veres,
  • J. Peischl,
  • J. Peischl,
  • S. Eilerman,
  • S. Eilerman,
  • R. Wild,
  • R. Wild,
  • S. S. Brown,
  • S. S. Brown,
  • C. R. Thompson,
  • C. R. Thompson,
  • T. Ryerson,
  • T. Hanisco,
  • G. M. Wolfe,
  • G. M. Wolfe,
  • J. M. St. Clair,
  • J. M. St. Clair,
  • M. Thayer,
  • F. N. Keutsch,
  • F. N. Keutsch,
  • S. Murphy,
  • J. de Gouw,
  • J. de Gouw

DOI
https://doi.org/10.5194/amt-10-2941-2017
Journal volume & issue
Vol. 10
pp. 2941 – 2968

Abstract

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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.