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AGU: Journal of Geophysical Research, Atmospheres

 

Keywords

  • Atmospheric measurements
  • NOAA
  • alkanes
  • benzene
  • methane
  • oil and gas

Index Terms

  • 0322 - Constituent sources and sinks
  • 0345 - Pollution: urban and regional
  • 0365 - Troposphere: composition and chemistry
  • 0394 - Instruments and techniques

Paper in Press

JOURNAL OF GEOPHYSICAL RESEARCH, doi:10.1029/2011JD016360

Hydrocarbon emissions characterization in the Colorado Front Range - A pilot study

Key Points
  • Emissions from oil and gas operations in the Denver Julesburg Basin
  • Multispecies observations are used to interpret CH4 variability in NE Colorado
  • Atmospheric observations are used to evaluate bottom-up inventories

Authors:

Gabrielle Petron

Gregory J. Frost

Benjamin R Miller

Adam I Hirsch

Stephen A. Montzka

Anna Karion

Michael K. Trainer

Colm Sweeney

Arlyn Elyzabeth Andrews

Lloyd Miller

Jonathan Kofler

Amnon Bar-Ilan

Edward J. Dlugokencky

Laura Patrick

Charles T. Moore

Thomas B. Ryerson

Carolina Siso

William Kolodzey

Patricia M. Lang

Thomas J. Conway

Paul C. Novelli

Kenneth Alan Masarie

Brad D. Hall

Doug Guenther

Duane R. Kitzis

John B Miller

David C. Welsh

Daniel E. Wolfe

William D. Neff

Pieter P. Tans

The multi-species analysis of daily air samples collected at the NOAA Boulder Atmospheric Observatory (BAO) in Weld County in northeastern Colorado since 2007 shows highly correlated alkane enhancements caused by a regionally distributed mix of sources in the Denver-Julesburg Basin. To further characterize the emissions of methane and non-methane hydrocarbons (propane, n-butane, i-pentane, n-pentane and benzene) around BAO, a pilot study involving automobile-based surveys was carried out during the summer of 2008. A mix of venting emissions (leaks) of raw natural gas and flashing emissions from condensate storage tanks can explain the alkane ratios we observe in air masses impacted by oil and gas operations in northeastern Colorado. Using the WRAP Phase III inventory of total volatile organic compound (VOC) emissions from oil and gas exploration, production and processing, together with flashing and venting emission speciation profiles provided by State agencies or the oil and gas industry, we derive a range of bottom-up speciated emissions for Weld County in 2008. We use the observed ambient molar ratios and flashing and venting emissions data to calculate top-down scenarios for the amount of natural gas leaked to the atmosphere and the associated methane and non-methane emissions. Our analysis suggests that the emissions of the species we measured are most likely underestimated in current inventories and that the uncertainties attached to these estimates can be as high as a factor of two.

Received 3 June 2011; accepted 20 December 2011.

Citation: Petron, G., et al. (2012), Hydrocarbon emissions characterization in the Colorado Front Range - A pilot study, J. Geophys. Res., doi:10.1029/2011JD016360, in press.