The Marcellus Shale is the largest natural gas deposit in the U.S. and rapid development of this resource has raised concerns about regional air pollution. A field campaign was conducted in the southwestern Pennsylvania region of the Marcellus Shale to investigate the impact of unconventional natural gas (UNG) production operations on regional air quality. Whole air samples were collected throughout an 8050 km(2) grid surrounding Pittsburgh and analyzed for methane, carbon dioxide, and C1-C10 volatile organic compounds (VOCs). Elevated mixing ratios of methane and C2-C8 alkanes were observed in areas with the highest density of UNG wells. Source apportionment was used to identify characteristic emission ratios for UNG sources, and results indicated that UNG emissions were responsible for the majority of mixing ratios of C2-C8 alkanes, but accounted for a small proportion of alkene and aromatic compounds. The VOC emissions from UNG operations accounted for 17 ± 19% of the regional kinetic hydroxyl radical reactivity of nonbiogenic VOCs suggesting that natural gas emissions may affect compliance with federal ozone standards. A first approximation of methane emissions from the study area of 10.0 ± 5.2 kg s(-1) provides a baseline for determining the efficacy of regulatory emission control efforts.

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NOTICE Th is document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge Notional Laboratory . It is subject to tevision or correction and therefore does not represent a final report .

The Office of Saline Water sponsored a program a t ORNL'to investigate the equipment components required for 50-Mgd and larger seawater distillation plants. T h i s program was undertaken t o determine if the large cbmponents and suitable materials were available from industry. Some of the equipment currently available was not designed for use with large multistage flash distillation plants, and the feasibility of using such equipment in desalting plants was evaluated along with factors relating to cost, performance, and estimated lifetime. The following detailed reports were prepared on the equipment components: