A much-delayed state air monitoring study meant to gauge the long-term health risks of living near Marcellus Shale operations found limited impacts to the air quality around the sites it examined and little risk of healthy residents getting sick from breathing the air nearby.

The study by the Pennsylvania Department of Environmental Protection was based on continuous and weekly sampling over more than a year at four sites surrounded by natural gas wells, compressor stations and processing facilities in Washington County in 2012 and 2013.

It found generally better air quality there than at more urban comparison sites in Washington County and similar levels of hazardous air pollutants at a background sampling site at a rural fruit orchard in Adams County, well outside of the Marcellus Shale drilling region.

But problems with the study, from data gaps and malfunctioning equipment to poor placement of monitors, made it less representative than its designers had hoped and less certain for drawing conclusions about the long-term heath implications of living near the Washington County sites or Marcellus Shale facilities elsewhere in the state.

A companion report by the Pennsylvania Department of Health and the federal Agency for Toxic Substances and Disease Registry found that while DEP’s data was sufficient for assessing the ambient air quality at the study sites, it had limited value for determining how emissions from natural gas infrastructure were affecting that air quality. Monitors for some types of pollutants were not downwind of the shale gas equipment they were meant to be measuring “on most of the days that samples were collected,” the health agencies wrote.

Pennsylvania environmental regulators embarked on the project after conducting a series of short-term surveys to provide snapshots of air quality at shale sites in three regions in 2010 and 2011, as the Marcellus drilling boom began. Those studies found that concentrations of detected chemicals were not likely to pose a health threat, but they were not designed to reflect longer-term exposures and they were later found to have omitted certain measurements from analysis.

The new report, which DEP acknowledged “was four years in the making,” set out to determine if there are any long-term risks to the public from shale gas sources. It was delayed by the massive amount of data to analyze as well as questions about its methodology and a lack of agency resources.

DEP posted the studies on its air quality website this week without any announcement.

http://www.post-gazette.com/powersource/policy-powersource/2018/07/...