Influence of Oil and Gas Emissions on Ambient Atmospheric Volatile Organic Compounds in Residential Areas of Northeastern Colorado

Abstract:

The Northern Front Range (NFR) region of Colorado has experienced rapid expansion in drilling of shale and tight sands oil and gas reservoirs in recent years due to advances in hydraulic fracturing technology, with over 24,000 wells currently in operation. This region has also been designated as a federal ozone non-attainment area by the U.S. EPA. High ozone levels are a significant health concern, as are potential health impacts from chronic exposure to primary emissions of volatile organic compounds (VOC) for residents living near wells. Here we present observations of ambient atmospheric VOC present in residential areas located in close proximity to wells in Erie, Colorado, and show that the C2-C5 alkanes are enhanced by a factor of 18 – 77 relative to the regional background, and present at higher levels than typically found in large urban centers. These data are combined with VOC observations from downtown Denver and Platteville, as well as with measurements conducted this summer in conjunction with the FRAPPE and DISCOVER-AQ flight campaigns, to investigate the spatial distribution of VOC enhancements in correlation with proximity to oil and gas production areas. We show that these compounds, including the BTEX aromatics, are elevated across the NFR, with highest levels in communities within the Greater Wattenberg Gas Field. These analyses demonstrate that VOC emissions from oil and gas operations represent a large area source for ozone precursors in the NFR.