Emissions from the expanding natural gas drilling industry increased in four of six air pollution categories in 2013 but releases of an important greenhouse gas declined, according to new data published by the Pennsylvania Department of Environmental Protection on Monday.
Acting DEP Secretary John Quigley said the increases were not unexpected because the industry is growing and regulators have expanded the number and types of facilities that have to report their emissions since the state first began collecting the data in 2011.
The number of well sites, processing facilities and compressor stations reporting emissions continued to climb in 2013. The emissions inventory includes 18.3 percent more well sites — from 8,700 to 10,300 — and 8.2 percent more midstream facilities than the previous year, DEP said.
Overall, air quality in Pennsylvania is showing improvements, Mr. Quigley said.
“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,” he said.
In 2013, emissions of volatile organic compounds from drilling rigs, well heads, hydraulic fracturing, compressor stations, leaks and other industry sources increased 19 percent from 2012 levels, rising from 4,024 to 4,790 tons per year, according to the DEP figures. Particulate matter, or soot, increased 12 percent, from 600 to 670 tons per year, and nitrogen oxides increased 8 percent, from 16,361 to 17,659 tons per year.
Volatile organic compounds (VOCs) include a variety of chemicals that may have short- and long-term adverse health effects, and they react with nitrogen oxides in sunlight to create lung-damaging pollution called ground-level ozone, or smog.
The natural gas industry’s VOC emissions made up nearly 18 percent of the total volatile organic compounds emitted in 2013 by all industrial stationary sources in Pennsylvania, according to the DEP.
Sulfur dioxide emissions from the natural gas industry increased 57 percent, from 101 tons per year in 2012 to 159 tons per year in 2013, but the sector’s emissions of the pollutant are relatively tiny — just 0.05 percent of the total sulfur dioxide emissions from all industrial sources statewide.
Methane and carbon monoxide emissions from natural gas drilling and production both decreased in 2013: methane by 13 percent and carbon monoxide by 10 percent.
Federal and state regulators are pushing the natural gas industry to cut emissions of methane, a potent greenhouse gas with over 80 times the heat-trapping power of carbon dioxide over a 20-year time span.
David Spigelmyer, president of the North Fayette-based Marcellus Shale Coalition, said the state’s data show that the industry has made important progress: year-over-year well site and midstream facility emissions averages fell and methane emissions declined despite increased activity.
He attributed the methane reductions in particular to “strong state-based regulations and innovative technologies,” which “are delivering meaningful environmental results.”
DEP began collecting emissions information from Marcellus Shale and other unconventional natural gas drilling and pipeline companies in 2011. The 2012 figures added data from processing plants and compressor stations that handle gas from conventional wells for the first time, while the 2013 inventory expanded to include compressor stations that support coal-bed methane production.
DEP data show that reductions in pollution from fuel switching and emissions controls at power plants across the state between 2011 and 2013 more than offset increases in pollution from the natural gas sector for most categories — including sulfur dioxide, particulates and nitrogen oxides — but not all.
Volatile organic compounds were rising from both the power plant and the natural gas sectors.
Kevin Stewart, director of environmental health for the American Lung Association of the Mid-Atlantic, said VOC emissions from natural gas operations are significant, and the degree to which their contents are hazardous toxic compounds still needs to be characterized.
“It remains a concern to the American Lung Association in Pennsylvania that the impacts of this increase in VOC emissions on air quality, especially for vulnerable populations including natural gas workers in close proximity, has not yet been adequately addressed,” he said.
Laura Legere: firstname.lastname@example.org
First Published April 20, 2015 2:22 PM