title: A personal exposure study employing scripted activities and paths in conjunction with atmospheric releases of perfluorocarbon tracers in Manhattan, New York.
abstract: A personal exposure study was conducted in New York City as part of the Urban Dispersion Program (UDP). It examined the contact of individuals with four harmless perflourocarbon tracers (PFT) released in Midtown Manhattan with approval by city agencies at separate locations, during two types of experiments, completed during each release period. Two continuous 1 h release periods separated by a 1.5 h ventilation time were completed on 3 October 2005. Stationary site and personal exposure measurements were taken during each period, and the first half hour after the release ended. Two types of scripted exposure activities are reported: Outdoor Source Scale, and Outdoor Neighborhood Scale; requiring 1- and 10-min duration samples, respectively. The results showed that exposures were influenced by the surface winds, the urban terrain, and the movements of people and vehicles typical in urban centers. The source scale exposure data indicated that local conditions significantly affected the distribution of each tracer, and consequently the exposures. The highest PFT exposures resulted from interaction of the scripted activities with local surface conditions. The range measured for 1- min exposures were large with measured values exceeding 5000 ppqv (parts per quadrillion by volume). The neighborhood scale measurements quantified exposures at distances up to seven blocks away from the release points. Generally, but not always, the PFT levels returned quickly to zero indicating that after cessation of the emissions the concentrations decrease rapidly, and reduce the intensity of local exposures. The near source and neighborhood personal exposure route results provided information to establish a baseline for determining how a release could affect both the general public and emergency responders, and evaluate the adequacy of re-entry or exit strategies from a local area. Finally, the data also show that local characteristics can produce "hot spots".
authors.affiliation: EOHSI, Robert Wood Johnson Medical School, UMDNJ, Piscataway, New Jersey 08854, USA. plioy@eohsi.rutgers.edu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lioy
authors.forename: Daniel
authors.initials: D
authors.lastname: Vallero
authors.forename: Gary
authors.initials: G
authors.lastname: Foley
authors.forename: Panos
authors.initials: P
authors.lastname: Georgopoulos
authors.forename: John
authors.initials: J
authors.lastname: Heiser
authors.forename: Tom
authors.initials: T
authors.lastname: Watson
authors.forename: Michael
authors.initials: M
authors.lastname: Reynolds
authors.forename: James
authors.initials: J
authors.lastname: Daloia
authors.forename: Sai
authors.initials: S
authors.lastname: Tong
authors.forename: Sastry
authors.initials: S
authors.lastname: Isukapalli
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D003625:Data Collection; D004781:Environmental Exposure; D005466:Fluorocarbons / Q000032:analysis* / Q000633:toxicity; D005843:Geography; D006801:Humans; D009519:New York City; D018570:Risk Assessment; D013997:Time Factors; D014505:Urban Population; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D005466:Fluorocarbons; D001335:Vehicle Emissions