@article{3e9301f4408b4e2083ed6a8f2110befc,
title = "Estimating Methane Emissions From Underground Coal and Natural Gas Production in Southwestern Pennsylvania",
abstract = "Production of coal and natural gas is responsible for one third of anthropogenic methane (CH4) emissions in the United States. Here we examine CH4 emissions from coal and natural gas production in southwestern Pennsylvania. Using a top-down methodology combining measurements of CH4 and ethane, we conclude that while Environmental Protection Agency inventories appear to report emissions from coal accurately, emissions from unconventional natural gas are underreported in the region by a factor of 5 (±3). However, production-scaled CH4 emissions from unconventional gas production in the Marcellus remain small compared to other basins due to its large production per well. After normalizing emissions by energy produced, total greenhouse gas emissions from Pennsylvania unconventional natural gas production produce half the carbon footprint compared to regionally produced coal, with carbon dioxide emissions from combustion being the dominant source of greenhouse gas emissions for both sources.",
author = "Barkley, {Z. R.} and T. Lauvaux and Davis, {K. J.} and A. Deng and A. Fried and P. Weibring and D. Richter and Walega, {J. G.} and J. DiGangi and Ehrman, {S. H.} and X. Ren and Dickerson, {R. R.}",
note = "Funding Information: Observational work by the University of Maryland was supported by the National Science Foundation (NSF grant CBET-1438400) and the National Institute of Science and Technology (NIST Cooperative Agreement 70NANB14H333). The Atmospheric Carbon and Transport (ACT)-America project is a NASA Earth Venture Suborbital 2 project funded by NASA's Earth Science Division (grant NNX15AG76G to Penn State). UMD aircraft data can be found at the website (http://www.atmos.umd. edu/∼rammpp/ archives/ArchiveFlightData.html). ACT-America aircraft data can be found at the website (https:// daac.ornl.gov/cgi-bin/dataset_ lister.pl?p=37). NCEP Reanalysis data were provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site (https://www.esrl.noaa.gov/psd/). Funding Information: Contrary to the large uncertainties associated with emissions from natural gas, emissions from coal mines are thought to be better understood. Due to the potential safety hazard of CH4 buildup inside underground mines, quarterly measurements of CH4 emissions from ventilation shafts, the largest source of CH4 emissions from underground coal mines, are required by the U.S. Mine Safety and Health Administration (U.S. Environmental Protection Agency, 2018a, 2018b). Smaller sources of coal-based CH4 emissions, such as from methane drainage systems, have less precise information available (Kirchgessner et al., 2000). Despite the large number of site measurements provided for underground coal mines, there have been few studies performing top-down estimates of individual coal basins in the United States. Such studies using atmospheric measurements can be useful even when thorough site-level data are available, as they can estimate emissions across a large area and thus detect sources that may be missed or underrepresented in bottom-up inventories. Funding Information: Observational work by the University of Maryland was supported by the National Science Foundation (NSF grant CBET-1438400) and the National Institute of Science and Technology (NIST Cooperative Agreement 70NANB14H333). The Atmospheric Carbon and Transport (ACT)-America project is a NASA Earth Venture Suborbital 2 project funded by NASA's Earth Science Division (grant NNX15AG76G to Penn State). UMD aircraft data can be found at the website (http://www.atmos.umd.edu/~rammpp/archives/ArchiveFlightData.html). ACT-America aircraft data can be found at the website (https://daac.ornl.gov/cgi-bin/dataset_lister.pl?p=37). NCEP Reanalysis data were provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site (https://www.esrl.noaa.gov/psd/). Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = apr,
day = "28",
doi = "10.1029/2019GL082131",
language = "English (US)",
volume = "46",
pages = "4531--4540",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "8",
}