TECHNIQUES, based on panel estimates, were developed for evaluating the odor and irritation intensities of undiluted diesel-engine exhaust gases or of various dilutions of these gases in air. Along with the estimates, chemical analyses were made to determine the concentrations of total aldehydes, formaldehyde, and oxides of nitrogen.
Statistically significant correlations were found between odor or irritation intensity estimates and the analytical data, but these correlations were too weak to permit accurate prediction of odor or irritation from chemical analyses.
Effects of some engine variables on diesel odor were studied. Possible means of reducing diesel odor are discussed.