Aerial study reveals methane and benzene emissions higher than expected

A new study of the oil and gas fields of Colorado, conducted by scientists from National Oceanic and Atmospheric Administration (NOAA) and the Cooperative Institute for Research in Environmental Sciences (CIRES), has revealed that methane and benzene emissions are respectively as much as three and seven times higher than Colorado state inventory.

Published on the 7th of May 2014, the aerial study recorded methane and non-methane hydrocarbon emissions over the densely pack oil and gas fields of the Denver-Julesburg Basin, over a two day period covering the 29th and 31st May 2013.

Comparing Colorado state inventory data with observational data, the report found that methane concentrations in the air were three times higher than state inventory, with oil and gas operations in the basin emitting around 19.3 metric tonnes of methane emissions every hour, which the authors calculate as a leak rate of 4.1 percent (± 1.5) of total gas produced.

Colorado State. Source: usgs.gov
Colorado State. (image source: usgs.gov)

Benzene, a volatile organic compound (VOC) harmful to humans, was seven times higher than state inventory, emitting around 173 ± 64 kg/hr.

The study reinforces concerns that fugitive emissions of methane and other non-methane hydrocarbons are running unabated, with gas operators and policy makers unable to halt fugitive emissions of gases harmful to human health.

“These discrepancies are substantial,” said lead author Gabrielle Petron, an atmospheric scientist with NOAA’s Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. “Emission estimates or ‘inventories’ are the primary tool that policy makers and regulators use to evaluate air quality and climate impacts of various sources, including oil and gas sources. If they’re off, it’s important to know.”

To read a copy of the peer-reviewed paper, click here.