PADEP Extends Long-Term Air Quality Study in Marcellus Region

The State Journal
2 August 2013
By Pam Kasey

The Pennsylvania Department of Environmental Protection announced Aug. 1 that it has extended its one-year, long-term air monitoring study in the Marcellus region in southwestern Pennsylvania through the end of this year.

"The use of natural gas holds great promise in continuing recent trends of cleaner air in this state, and the data from this study will allow us to make sound decisions for the long-term," DEP Acting Secretary E. Christopher Abruzzo said.

"Our study, which is stationed in one of the most active drilling regions in the state, will help us to identify potential air quality–related risks associated with drilling, processing and transporting natural gas," Abruzzo said.  

In July 2012, DEP announced it would conduct a long-term study in southwestern Pennsylvania to measure ambient air concentrations of pollutants.

The study, designed to identify potential health risks associated with the extraction, processing and transportation of natural gas, is under way in Chartiers Township, in Washington County. Both methane, or "dry" gas, and natural gas liquids are processed and moved to sale there via compressor stations and pipeline networks.

Samples collected during the study will be subjected to rigorous quality assurance and data validation criteria.

A final report is expected in the spring of 2014.

A 60-page technical support document released by the agency on Aug. 1 makes unpublished information about the study's scope and process available to the public.

In 2010 and 2011, PADEP conducted three short-term ambient air quality sampling studies in the southwest, north-central and northeast parts of the state. The agency reported from those studies that it detected no level of any pollutant that would violate federal ambient air quality standards. It also reported that it did not identify concentrations of any compound associated with Marcellus Shale drilling activities that would be likely to trigger air-related health issues.

The main monitoring site for the long-term study includes sampling for ground-level ozone, particulate matter, carbon monoxide, nitrogen oxides, hydrogen sulfide and methane. The air will also be tested for more than 60 volatile organic compounds, including hazardous air pollutants, and meteorological data will be collected continuously.

DEP is monitoring for volatile organic compounds and collecting meteorological data at three additional sites in Chartiers and Hickory townships in Washington County as well. Of the two additional Chartiers Township sites, one is upwind of MarkWest Liberty Midstream & Resources Houston, Pa. gas processing plant and the other is downwind of the Brigich compressor station. The site in Hickory Township will be located downwind of the Stewart compressor stations.

The agency's media release said the long-term study is the latest effort to ensure that natural gas resources are developed responsibly. Earlier this year, PADEP announced a revised general permit for compressor stations and gas processing facilities that included significantly lower allowable emissions limits.

A PADEP emissions inventory submitted to U.S. Environmental Protection Agency in December 2012 showed significant reductions in sulfur dioxide emissions in Pennsylvania between 2008 and 2011. The agency calculated that those reductions, which it attributed primarily to the deactivation of coal-fired power stations, installation of emissions controls at remaining stations and the conversion to natural gas from coal, represent an annual public health benefit of $14 billion to $37 billion, based on EPA methodologies.

The agency said the inventory, which for the first time included unconventional gas operations, also showed significant reductions in nitrogen oxide, carbon monoxide, volatile organic compounds and particulate matter during that same time period.

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