Spatial Distribution of Methane in Pennsylvania During June 2012

In these past few years there have being significant changes in the knowledge of sources and sinks of methane. Natural gas exploration and mining are proceeding at a rapid pace in places such as Pennsylvania, particularly with the Marcellus Shale activities. Methane is responsible for the 15% of atmospheric warming. Given that methane is an important greenhouse gas, it is crucial to understand its sources and sinks. A field campaign was conducted for a period of six days, from June 21, 2012 to June 27, 2012 (excluding June 23 and 24, 2012) to determine the ambient concentrations of methane and carbon dioxide. Gas concentrations were measured using an instrument based on Cavity Ring-Down Spectrometry (model G2201-I, Picarro Inc., Palo Alto, CA). The instrument was deployed on a mobile van which was driving to places where natural gas wells were under development and in operation, and to locales occupied by cattle farms. Plots for the resulting data were created in Matlab. The figures were plotted hourly, for each day the mobile campaign was conducted. The goal was to determine methane levels around cattle farms and at places near natural gas wells under development and (old and new) operations. In the rural atmosphere and around wells under development the ambient levels of methane were about 1.75 ppm. However, in areas with old wells and pipelines, the atmosphere was enriched with methane, with mixing ratios reaching higher than 2.2 ppm. Also, ambient methane levels around cattle farms were enhanced, with mixing ratios reaching about 4 ppm.