REGIONAL CHARACTERISTICS AND POTENTIAL ATMOSPHERIC IMPACTS OF VOLATILE ORGANIC COMPOUNDS (VOCS) EMITTED FROM OIL AND NATURAL GAS OPERATIONS IN SEVERAL MAJOR SHALE PLAYS ACROSS THE UNITED STATES

The U.S. Energy Information Administration has reported a sharp increase in domestic oil and natural gas production from “unconventional” reserves (e.g., shale and tight sands) between 2005 and 2012. The recent growth in drilling and fossil fuel production has led to environmental concerns regarding local air quality. Depending on the particular shale formation, raw natural gas can contain significant amounts of volatile organic compounds (VOCs) in the form of natural gas liquids (e.g., ethane, propane, butanes) and natural gas condensate (e.g., pentanes, cycloalkanes, and aromatics). VOCs, in the presence of nitrogen oxides and sunlight, can cause the photochemical formation of ozone and particulate matter both of which are harmful to human health and degrade local air quality. An extensive set of VOCs and other trace gases were measured in the ambient air over several of the largest shale gas plays in the United States including the Uintah Basin (Utah), Denver Basin (Colorado), Haynesville shale (Texas/Louisiana), Fayetteville shale (Arkansas), and Marcellus shale (Pennsylvania). In this presentation, we will compare the ambient air composition of VOCs measured near each of these shale gas plays in order to 1) show that the typical VOC source signature from oil and natural gas operations is distinct and can be clearly distinguished from typical urban emissions associated with on-road combustion sources, and 2) assess the potential atmospheric impacts of VOC emissions from the oil and gas sector, such as the photochemical production of ozone and oxygenated VOCs (e.g., aldehydes).