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First responders (FRs) present at Ground Zero within the critical first 72 h after the World Trade Center (WTC) collapse have progressively exhibited significant respiratory injury. The majority (96%) of WTC dusts were10 μm and no studies have examined potential health effects of this size fraction. This study sought to develop a system to generate and deliver supercoarse (10-53 μm) WTC particles to a rat model in a manner that mimicked FR exposure scenarios. A modified Fishing Line generator was integrated onto an intratracheal inhalation (ITIH) system that allowed for a bypassing of the nasal passages so as to mimic FR exposures. Dust concentrations were measured gravimetrically; particle size distribution was measured via elutriation. Results indicate that the system could produce dusts with 23 μm mass median aerodynamic diameter (MMAD) at levels up to ≥1200 mg/m(3). To validate system utility, F344 rats were exposed for 2 h to ≈100 mg WTC dust/m(3). Exposed rats had significantly increased lung weight and levels of select tracer metals 1 h after exposure. Using this system, it is now possible to conduct relevant inhalation exposures to determine adverse WTC dusts impacts on the respiratory system. Furthermore, this novel integrated Fishing Line-ITIH system could potentially be used in the analyses of a wide spectrum of other dusts/pollutants of sizes previously untested or delivered to the lungs in ways that did not reflect realistic exposure scenarios.

Personal exposures to fine particulate matter air pollution (PM(2.5)), and to its traffic-related fraction, were investigated in a group of urban children with asthma. The relationships of personal and outdoor school-site measurements of PM(2.5) and elemental carbon (EC) were characterized for a total of 40 fifth-grade children. These students, from four South Bronx, NY schools, each carried air pollution monitoring equipment with them for 24 h per day for similar to 1 month. Daily EC concentrations were estimated using locally calibrated reflectance of the PM(2.5) samples. Personal EC concentration was more closely related to outdoor school-site EC (median subject-specific: r=0.64) than was personal PM(2.5) to school-site PM(2.5) concentration (median subject-specific: r=0.33). Regression models also showed a stronger, more robust association of school site with personal measurements for EC than those for PM(2.5). High traffic pollution exposure was found to coincide with the weekday early morning rush hour, with higher personal exposures for participants living closer to a highway (

In December 2006, the U.S. Environmental Protection Agency (EPA) sponsored a 2-day workshop on "Interpretation of Epidemiologic Studies of Multipollutant Exposure and Health Effects" in Chapel Hill, NC. The final session at this workshop was devoted to assessing the biological plausibility of epidemiological findings with regard to criteria air pollutants. The presentations and the panel contributions of this last session primarily focused on controlled exposure studies and led to wide-ranging discussions, some of which were provocative. The panel summary provides some guidance to future evaluations of the biological plausibility of the epidemiological reports on criteria pollutants and is intended to stimulate thinking, without drawing any definitive conclusions. This paper does not approach, nor was it intended to approach, the more formal analytical approach such as that used in EPA's development of its Science Assessment Document for the criteria pollutants.