But Andrew Paterson, vice president of technical and regulatory affairs at the Marcellus Shale Coalition, said the extraction industry's air emissions represent only one side of the pollution ledger. Electrical utilities are switching from coal to cleaner-burning natural gas, for example, enabling an overall reduction in emissions, he said.
Indeed, the DEP report shows that statewide air emissions from point sources like power plants plummeted between 2008 — when the last inventory was taken — and 2011.
"When you look at the whole picture, you're seeing a decline in emissions," he said Friday. "But even if you are only focused on emissions from drilling and fracking, it's still a very small number when compared to other manmade emissions."
A new study from RAND Corp. tries to quantify the economic impact of drilling-related air pollution in Pennsylvania. The study, released Thursday, estimated that air pollution caused between $7.2 million and $32 million in health and environmental damages for 2011. By comparison, the study estimated a single coal-fired power plant caused $75 million in damages in 2008.
But the study's authors say the air impacts are nevertheless a concern in heavily drilled regions of the state.
"When you compare the industry emissions to all the sources of emissions we have in the state, you could say to yourself, 'Who cares?'" said Aimee Curtright, one of the study's co-authors. But "if you're downwind of a (natural-gas) compressor station, and you're a long way from the coal-fired power plant, what matters to you and your health is the compressor station that's upwind. It's a question of where you sit."