ABSTRACT
Recent technological innovations in natural gas extraction-namely the combined use of horizontal drilling and hydraulic fracturing-are enabling access to vast new natural gas resources contained in shale deposits across the United States (Kargbo et al 2010, Mooney 2011). The Marcellus Shale formation is the largest US shale gas deposit and has contributed significantly in recent years to increased US natural gas production (US DOE EIA 2012a, 2012b). The rapid development of this resource has been touted as both an economic boon (Considine et al 2011, Marcellus Shale Coalition 2012) and a potential environmental mistake for the region (PennEnvironment Research and Policy Center 2012). Environmental concerns
often relate to risks to water resources (Ground Water Protection Council and ALL Consulting 2009, Mooney 2011). However, utilizing natural gas from shale deposits also produces air emissions of various types during extraction, transportation, and end use.
