The health implications of unconventional natural gas development in Pennsylvania.

We investigate the health impacts of unconventional natural gas development of Marcellus shale in Pennsylvania between 2001 and 2013 by merging well permit data from the Pennsylvania Department of Environmental Protection with a database of all inpatient hospital admissions. After comparing changes in hospitalization rates over time for air pollution-sensitive diseases in counties with unconventional gas wells to changes in hospitalization rates in nonwell counties, we find a significant association between shale gas development and hospitalizations for pneumonia among the elderly, which is consistent with higher levels of air pollution resulting from unconventional natural gas development. We note that the lack of any detectable impact of shale gas development on younger populations may be due to unobserved factors contemporaneous with drilling, such as migration.