Emission Rates of Volatile Organic Compounds from Natural Gas Extraction and Production Activities in Colorado

Volatile Organic Compounds (VOCs) can be emitted from the different processes involved in unconventional methods of extraction of oil and natural gas.  According to the U.S. Geological Survey, there may be about 40 times more natural gas in tight sand and shale formations in western Colorado, than previously estimated.  In order to access these reservoirs unconventional methods of oil and gas extraction will be employed.  Accurate measurements of emission rates of VOCs (air toxics and ozone precursors) can be a valuable tool in estimating the local and regional effects of emissions from oil and natural gas activities on the environment and human health.  Data from two studies conducted in western Colorado and the Colorado Front Range are presented on the emission rates of VOCs from drilling, fracking, flowback, and production sites.  Emission rates of VOCs were calculated using the Tracer Ratio Method (TRM).  Acetylene was used as the tracer gas for TRM and three minute integrated whole air samples were used to measure the concentrations of acetylene and other VOCs downwind of oil and gas sites.  The differences in VOC emission rates at different locations and during various operations will be presented.