title: Spatial analysis of volatile organic compounds in South Philadelphia using passive samplers.
abstract: Select volatile organic compounds (VOCs) were measured in the vicinity of a petroleum refinery and related operations in South Philadelphia, Pennsylvania, USA, using passive air sampling and laboratory analysis methods. Two-week, time-integrated samplers were deployed at 17 sites, which were aggregated into five site groups of varying distances from the refinery. Benzene, toluene, ethylbenzene, and xylene isomers (BTEX) and styrene concentrations were higher near the refinery's fenceline than for groups at the refinery's south edge, mid-distance, and farther removed locations. The near fenceline group was significantly higher than the refinery's north edge group for benzene and toluene but not for ethylbenzene or xylene isomers; styrene was lower at the near fenceline group versus the north edge group. For BTEX and styrene, the magnitude of estimated differences generally increased when proceeding through groups ever farther away from the petroleum refining. Perchloroethylene results were not suggestive of an influence from refining. These results suggest that emissions from the refinery complex contribute to higher concentrations of BTEX species and styrene in the vicinity of the plant, with this influence declining as distance from the petroleum refining increases.
  
  
  CONCLUSIONS
  Passive sampling methodology for VOCs as discussed here is employed in recently enacted U.S. Environmental Protection Agency Methods 325A/B for determination of benzene concentrations at refinery fenceline locations. Spatial gradients of VOC concentration near the refinery fenceline were discerned in an area containing traffic and other VOC-related sources. Though limited, these findings can be useful in application of the method at such facilities to ascertain source influence.
authors.affiliation: a National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Shaibal
authors.initials: S
authors.lastname: Mukerjee
authors.affiliation: b Alion Science and Technology , Durham , North Carolina , USA.
authors.forename: Luther A
authors.initials: LA
authors.lastname: Smith
authors.affiliation: c National Risk Management Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Eben D
authors.initials: ED
authors.lastname: Thoma
authors.affiliation: a National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Karen D
authors.initials: KD
authors.lastname: Oliver
authors.affiliation: a National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Whitaker
authors.affiliation: c National Risk Management Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Tai
authors.initials: T
authors.lastname: Wu
authors.affiliation: a National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.
authors.forename: Maribel
authors.initials: M
authors.lastname: Colon
authors.affiliation: a National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency, Research Triangle Park , North Carolina , USA.|d Senior Environmental Employment Program, Research Triangle Park , North Carolina , USA.
authors.forename: Lillian
authors.initials: L
authors.lastname: Alston
authors.affiliation: b Alion Science and Technology , Durham , North Carolina , USA.
authors.forename: Tamira A
authors.initials: TA
authors.lastname: Cousett
authors.affiliation: b Alion Science and Technology , Durham , North Carolina , USA.
authors.forename: Casson
authors.initials: C
authors.lastname: Stallings
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D015143:Philadelphia; D062206:Spatial Analysis; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D055549:Volatile Organic Compounds