New data released by the Pennsylvania Department of Environmental Protection (DEP) shows that between 2012 and 2013, as natural gas drilling increased significantly in the state, so too did air emissions in several categories of contaminants.

The air emissions data, which has been collected by the agency from midstream facilities and unconventional gas wells since 2011, has expanded in recent years to include compressor stations that serve coalbed methane and conventional oil and gas wells.  Owners and operators are required to report the data to DEP under Pennsylvania's Air Pollution Act.

"The increases were not unexpected," Acting DEP Secretary John Quigley said. "The industry is growing, and each year we are expanding the types of and number of facilities from which we collect data so that we have a more comprehensive understanding of air quality issues."

Natural gas production in the state has increased significantly since 2012, going from 2.04 Tcf at that time to 3.3 Tcf in 2013 and upwards of 4 Tcf last year (see Shale Daily, Feb. 17; Feb. 20, 2014; March 6, 2013). Between 2012 and 2013 sulfur dioxide emissions related to the oil and gas industry increased 57%, volatile organic compounds (VOCs) increased 19%, particulate matter rose by 12% and nitrogen oxides increased by 8%, DEP said.

But the number of wells reporting also increased dramatically, going from 8,687 in 2012 to 10,277 in 2013, while midstream facilities went from 400 to 433 during the period. Still, methane emissions decreased 13%, from 123,884 tons per year to 107,945, and carbon monoxide emissions also decreased by 10%, from 7,350 tons per year to 6,606.

"This data reflects our industry's clear commitment to enhancing air quality and protecting our environment," said Marcellus Shale Coalition President Dave Spigelmyer. "The sharp decline in methane emissions, despite increased activity, is particularly encouraging and reinforces the fact that our strong state-based regulations and innovative technologies are delivering  meaningful environmental results.”

After decades of using costly diesel fuel, more operators in the Northeast and across the country are turning to cleaner produced natural gas to power their operations, from fleet vehicles to drilling and completion tasks (see Shale Daily, Sept. 29, 2014). They’re also focused on capturing fugitive methane emissions and flaring less gas in the face of tighter state and federal regulations.

In Pennsylvania, operators could face tighter environmental standards under new draft rules currently in the public comment phase that are expected to be implemented next year (see Shale Daily, March 9). Some industry sources said when it released the data on Monday, DEP didn’t fully acknowledge the strides energy companies have made in making reductions in the carbon monoxide and methane categories.

But the agency has also conducted several independent air quality tests at drilling and processing sites across Pennsylvania since 2010 (seeShale Daily, July 25, 2012). It acknowledged after those tests that it found no emissions levels that would trigger health concerns, including a short-term air sampling at a natural gas compressor in 2013 that the agency said posed a minimal threat.

"While we are experiencing some increases in emissions from the natural gas sector, overall, our air quality continues to improve due to emissions reductions from other point sources such as electric generating units," Quigley said.