Generation and characterization of gasoline engine exhaust inhalation exposure atmospheres.

Exposure atmospheres for a rodent inhalation toxicology study were generated from the exhaust of a 4.3-L gasoline engine coupled to a dynamometer and operated on an adapted California Unified Driving Cycle. Exposure levels were maintained at three different dilution rates.

Carbonyl and nitrogen dioxide emissions from gasoline- and diesel-powered motor vehicles.

Carbonyls can be toxic and highly reactive in the atmosphere. To quantify trends in carbonyl emissions from light-duty (LD) vehicles, measurements were made in a San Francisco Bay area highwaytunnel bore containing essentially all LD vehicles during the summers of 1999, 2001, and 2006. The LD vehicle emission factor for formaldehyde, the most abundant carbonyl, did not change between 1999 and 2001, then decreased by 61 +/- 7% between 2001 and 2006.

Generation and characterization of four dilutions of diesel engine exhaust for a subchronic inhalation study.

Exposure atmospheres for a rodent inhalation toxicology study were generated from the exhaust of a 2000 Cummins ISB 5.9L diesel engine coupled to a dynamometer and operated on a slightly modified heavy-duty Federal Test Procedure cycle. Exposures were conducted to one clean air control and four diesel exhaust levels maintained at four different dilution rates (300:1, 100:1, 30:1, 10:1) that yielded particulate mass concentrations of 30, 100, 300, and 1000 microg/m3.

Speciated ambient carbonyls in Rio de Janeiro, Brazil.

Carbonyls in urban air continue to receive scientific and regulatory attention as toxic air contaminants and for their important role in photochemical smog. However, few data are available for speciated carbonyls in urban air. Ambient concentrations of up to 61 carbonyls have been measured in Rio de Janeiro, Brazil.

Airborne carbonyls from motor vehicle emissions in two highway tunnels.

Carbonyls (aldehydes and ketones) continue to receive scientific and regulatory attention as toxic air contaminants, mutagens, and carcinogens. Vehicle emissions are a major source of carbonyls in outdoor air, but information about the nature and magnitude of carbonyl emissions by motor vehicles is limited. The objective of this study was to identify speciated carbonyls emitted by motor vehicles under real-world, on-road conditions and to calculate on-road carbonyl emission factors.