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Atmospheric Emission Characterization of Marcellus Shale Natural Gas Development Sites

Goetz, J. Douglas, Floerchinger, Cody, Fortner, Edward C., Wormhoudt, Joda, Massoli, Paola, Knighton, W. Berk, Herndon, Scott C., Kolb, Charles E., Knipping, Eladio, Shaw, Stephanie L., DeCarlo, Peter F.
Environmental Science & Technology 2015 v.49 no.11 pp. 7012-7020
carbon dioxide, emissions, methane, natural gas, pollutants, shale, uncertainty, volatile organic compounds
Limited direct measurements of criteria pollutants emissions and precursors, as well as natural gas constituents, from Marcellus shale gas development activities contribute to uncertainty about their atmospheric impact. Real-time measurements were made with the Aerodyne Research Inc. Mobile Laboratory to characterize emission rates of atmospheric pollutants. Sites investigated include production well pads, a well pad with a drill rig, a well completion, and compressor stations. Tracer release ratio methods were used to estimate emission rates. A first-order correction factor was developed to account for errors introduced by fenceline tracer release. In contrast to observations from other shale plays, elevated volatile organic compounds, other than CH₄ and C₂H₆, were generally not observed at the investigated sites. Elevated submicrometer particle mass concentrations were also generally not observed. Emission rates from compressor stations ranged from 0.006 to 0.162 tons per day (tpd) for NOₓ, 0.029 to 0.426 tpd for CO, and 67.9 to 371 tpd for CO₂. CH₄ and C₂H₆ emission rates from compressor stations ranged from 0.411 to 4.936 tpd and 0.023 to 0.062 tpd, respectively. Although limited in sample size, this study provides emission rate estimates for some processes in a newly developed natural gas resource and contributes valuable comparisons to other shale gas studies.