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SMOG CHAMBERS: A TOOL TO EXAMINE EFFECTS OF PHOTOCHEMICALLY AGED AIR POLLUTANTS ON BIOLOGICAL SYSTEMS
Citation:
SEXTON, K., M. DOYLE, K. DE BRUJINE, S. EBERVILLER, H. JEFFERIES, AND I. JASPERS. SMOG CHAMBERS: A TOOL TO EXAMINE EFFECTS OF PHOTOCHEMICALLY AGED AIR POLLUTANTS ON BIOLOGICAL SYSTEMS. Presented at International Society of Exposure Assessment Annual Meeting, Tucson, AZ, October 30 - November 03, 2005.
Description:
Irradiative exposure chambers or 'Smog chambers' have been used at the University of North Carolina for over 30 years to study photochemically active mixtures of volatile organic compounds and their transformation products (a significant sub-set of Hazardous Air Pollutants, HAPs), typically found in urban areas, and to produce data suitable to test air quality simulation models for these systems. We have interfaced in-vitro gaseous exposure systems to these smog chambers, allowing A549 cells, an alveolar type II-like cell line, and primary human bronchial epithelial cells, grown on membranous support (TranswellÔ inserts) to be exposed in real-time, directly to the gaseous photochemical mixture or 'control' mixture for 5 hours and analyzed for cytotoxicity and cytokine gene expression 9 hours post-exposure. We have shown using these techniques that photochemical products of primary pollutant mixtures, representing atmospheric transformations, can be more toxic than the precursor pollutants, beyond the effects of the ozone alone formed in these systems. Further, by conducting toxicity exposures to prepared mixtures of identified transformation products, confirmation and evaluation tests can be performed, which can be used to determine the presence of other toxic products. A new smog chamber system with animal facilities has been built which has exposure systems for in-vivo tests, to be performed concurrently with the in-vitro tests. The unique net benefit of the overall research program is the integrated results from a single source of experiments: the time-concentration chemical measurements from these smog chamber experiments can be used to further develop air quality simulation models needed to predict the transformation products necessary for exposure assessments; the toxicological results can be used to assist in relative risk assessment calculations.