Title: Regional to Hemispheric Atmospheric Impacts of U.S. Oil and Natural Gas Development

Abstract: The development of hydraulic fracturing drilling techniques (‘fracking’) for oil and natural gas (O&NG) extraction has triggered a steep rise in drilling activity and O&NG production in the U.S.  Atmospheric emissions, including those of methane, volatile organic compounds (VOC), and nitrogen oxides, have become a concern for local and regional air quality, and climate forcing on regional, continental and global scales.   Data collected from a series of field campaigns and year-round continuous atmospheric monitoring within and near O&NG basins has yielded a rich data set for characterizing O&NG related emissions.  Large scale impacts are reflected in global observations from the NOAA-INSTAAR global VOC monitoring program, as well as from continuous in-situ monitoring at Summit, Greenland.   Observed regional and hemispheric changes in absolute O&NG VOC concentrations, of VOC ratios, and in the methane to ethane ratio (MER) are indicative of changes in the contribution of emission sectors and O&NG producing regions.  In the Northern Hemisphere, declining trends of O&NG halted during 2005-2010, reversed to increasing concentrations during the US O&NG boom until 2014, and have since been sensitive to fluctuations in new drilling and production driven by the global O&NG market.   Field observations and modeling show that increases in O&NG VOC emissions have a profound impact on regional surface ozone, in part offsetting emission reductions of ozone precursors made in mobile source and power generation sectors, and that O&NG emissions are exerting an increasing relative contribution to exceedances of the ozone air quality standard in and near O&NG basins and downwind regions.