VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

greater sensitivity to agents which constrict breathing passages) comparable to NIST 1649a and to a greater degree than ROFA. Doses of 10 and 32 .ug administered directly into the airways, or inhalation at 10 mg/m’, did not induce significant inflammation or hyperresponsiveness. The significant degree of airway hyperresponsiveness induced by the high dose of WTC PM2.5 implies that components of the dust can promote mechanisms of airway obstruction.

The results fi-om these studies indicate that a high dose of WTC dust as PM2.5 would be necessary to elicit effects in healthy people. Hypothetical calculations are presented indicating that a healthy worker at Ground Zero would have to inhale about 425 ug/m-’ WTC PM2 5 for 8 hours to achieve the same dose per tracheobronchial surface area as occurred with the high dose of WTC PM2.5 used in the mouse studies. These high concentrations are conceivable in the aftermath of the collapse of the towers when rescue and salvage efforts were in effect. Therefore a healthy worker without respiratory protection could have inhaled enough WTC PM2 5 to cause pulmonary inflammation, airway hyperresponsiveness, and manifestations of sensory irritation such as cough. Species differences in responses to inhalation of WTC PM2 5 are unknown and were not considered in these calculations. Individuals who are especially sensitive to inhalation of dusts, such as asthmatics, may experience these effects at lower doses of inhaled WTC PM2 5. These studies suggest that most healthy people would not respond to a single exposure to moderately high WTC PM2.5 levels (about 130 pg/m’ or less for 8 hours) with any adverse respiratory responses. However, it should be emphasized that the effects of chronic (long-term) or repeated exposures to lower levels of WTC PM2.5, or the persistence of any respiratory effects are unknown and were not components of this study. Although only fine PM2.5 was tested in these experiments, its composition was similar to coarser PM, suggesting that biological responses to both size fractions within the respiratory system may be similar. The results of these studies will need to be placed within the context of an overall risk assessment for exposures to pollutants generated by the World Trade Center disaster.

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