A Year of Passive Hydrocarbon Monitoring Next to an Eagle Ford Well Site

The recent production boom in the U.S. oil and natural gas industry has raised environmental concerns, including an increase of hydrocarbon emissions to the atmosphere. A subset of emitted hydrocarbons are hazardous air pollutants (HAPs), and it is important to determine hydrocarbon exposure from oil and gas sites to evaluate potential dangers to the environment and to residents nearby. For this study, passive air sampling (with Radiello samplers) was used to monitor the concentrations of various hydrocarbons near an oil site in the Texas Eagle Ford shale over the span of 52 weeks. Analysis of samples was conducted with thermal desorption and gas chromatography with flame ionization detection. Benzene, a hazardous air pollutant, was targeted due to its carcinogenicity. Local weather data was used in conjunction with the hydrocarbon data to determine dispersion trends from the site. Factors that could affect the spread of the hydrocarbons, including wind direction, wind speed, and temperature were investigated. We found that benzene levels showed a slight increase in the winter months. This increase was likely due to a seasonal shift in the winter from dominantly southerly to northerly winds. The site is located to the northwest of the samplers, so more northerly winds would result in a higher percentage of emissions traveling from the site to the samplers. Dispersion of hydrocarbon emissions from oil sites depend on many meteorological conditions including wind speed, wind direction, boundary levels, etc.