| Title: | Laboratory evaluation of a prototype photochemical chamber designed to investigate the health effects of fresh and aged vehicular exhaust emissions |
| Author(s): | Papapostolou V; Lawrence JE; Diaz EA; Wolfson JM; Ferguson ST; Long MS; Godleski JJ; Koutrakis P; |
| Address: | "Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA. vpapapos@hsph.harvard.edu" |
| DOI: | 10.3109/08958378.2011.587034 |
| ISSN/ISBN: | 1091-7691 (Electronic) 0895-8378 (Print) 0895-8378 (Linking) |
| Abstract: | "Laboratory experiments simulating atmospheric aging of motor vehicle exhaust emissions were conducted using a single vehicle and a photochemical chamber. A compact automobile was used as a source of emissions. The vehicle exhaust was diluted with ambient air to achieve carbon monoxide (CO) concentrations similar to those observed in an urban highway tunnel. With the car engine idling, it is expected that the CO concentration is a reasonable surrogate for volatile organic compounds (VOCs) emissions. Varying the amount of dilution of the exhaust gas to produce different CO concentrations, allowed adjustment of the concentrations of VOCs in the chamber to optimize production of secondary organic aerosol (SOA) needed for animal toxicological exposures. Photochemical reactions in the chamber resulted in nitric oxide (NO) depletion, nitrogen dioxide (NO(2)) formation, ozone (O(3)) accumulation, and SOA formation. A stable SOA concentration of approximately 40 mug m(-)(3) at a chamber mean residence time of 30 min was achieved. This relatively short mean residence time provided adequate chamber flow output for both particle characterization and animal exposures. The chamber was operated as a continuous flow reactor for animal toxicological tests. SOA mass generated from the car exhaust diluted with ambient air was almost entirely in the ultrafine mode. Chamber performance was improved by using different types of seed aerosol to provide a surface for condensation of semivolatile reaction products, thus increasing the yield of SOA. Toxicological studies using Sprague-Dawley rats found significant increases of in vivo chemiluminescence in lungs following exposure to SOA" |
| Keywords: | "Aerosols/analysis/toxicity Air Pollutants/*analysis/toxicity Animals *Atmosphere Exposure Chambers Inhalation Exposure/adverse effects Male *Photochemistry Rats Rats, Sprague-Dawley Toxicity Tests Vehicle Emissions/*analysis/toxicity Volatile Organic Comp;" |
| Notes: | "MedlinePapapostolou, Vasileios Lawrence, Joy E Diaz, Edgar A Wolfson, Jack M Ferguson, Stephen T Long, Mark S Godleski, John J Koutrakis, Petros eng P30 ES000002/ES/NIEHS NIH HHS/ P30ES000002/ES/NIEHS NIH HHS/ Evaluation Study Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. England 2011/06/22 Inhal Toxicol. 2011 Jul; 23(8):495-505. doi: 10.3109/08958378.2011.587034" |
