Diesel Exhaust Odor Analysis by Sensory Techniques

The odor profile method has been applied to the measurement and analysis of diesel exhaust odor. The human sensory panel has described the odor of diluted exhaust and analytical fractions isolated from the exhaust in terms of total intensity of aroma (TIA), and individual odor character notes. For convenience, diesel exhaust odor can be described in two character groups-oily-kerosene and smoky-burnt odor. The odorous species were determined by detailed chemical analyses supported by comparative data from reference compounds. To achieve reliable quantitative odor intensity measurements, it was necessary to present the odor panel with a series of concentrations (dilutions) of exhaust in air over a wide range. The odor intensity at a given exhaust concentration is computed from a least squares analysis of the entire panel data. The results demonstrate an odor intensity range of slight to moderately strong for diesel exhaust at 1000:1 dilution.