Acute toxicity of gasoline and ethanol automobile engine exhaust gases.

A comparative inhalation exposure study was performed to investigate the potential health effect of gasoline and ethanol engine exhaust fumes. Wistar rats housed in inhalation chambers were exposed to test atmospheres of various concentrations of carbon monoxide (CO) and gasoline and ethanol exhaust fumes diluted with air. CO level, temperature, relative humidity and flow rate were monitored continually to control the gas concentration and the environment. The dilution method gave a concentration within 1.0% of the target. The LC50s for 3-h exposures were determined for the 3 test atmospheres. The results demonstrated that the acute toxicity, in terms of LC50, of the gasoline-fuelled engine was significantly higher than that of the ethanol-fuelled engine.