We've reported previously on air emissions studies done in Pennsylvania (see here, e.g.). The Pennsylvania Department of Environmental Protection (PA DEP) is now requiring certain E&P companies to submit air emissions data regarding their facilities for 2011 by March 1, 2012: "'The use of natural gas for fuel will have very beneficial impacts on air quality, and we want to ensure we are protecting the quality of Pennsylvania’s air as we access and bring to market this abundant, domestic fuel source,' DEP Secretary Mike Krancer said. *** This week, the agency is initially asking 99 operators identified as being involved in natural gas development, production, transmission, processing and related activities to respond with the necessary data." (From this press release.)
For more, see here.