The News and Sentinel is reporting on a recent air study in West Virginia concluding that the state's air quality will not be impacted by natural gas drilling operations in the state: "The report was created by the West Virginia Department of Environmental Protection's Office of Oil and Gas. It looked at the impact of fracking, a process in which water and sand are injected underground to access deposits of shale oil and gas. *** The report relied on U.S. Environmental Protection Agency data at a Monongalia County elementary school. *** The report says there were no indications of a public health emergency or threat based on air quality monitoring data."
[Update: The same appears to be true for a recent study regarding a Pennsylvania compressor station. See this article from the Lewistown Sentinel ("The Department of Environmental Protection says tests near a natural gas compressor plant in eastern Pennsylvania don't show excessive levels of nitrogen oxide pollution.").]