Psychophysical methodology in odour pollution research: the measurement of poultry house odour detectability and intensity

Abstract

The main purpose of the present experiment was to develop a methodology for the measurement of the detectability and intensity of agricultural odorants using established psychological procedures. Twelve odorants from three poultry houses differing amongst others in their manure treatment systems were bag sampled and investigated in a controlled laboratory setting. Using a simple one port dilution olfactometer, six subjects judged the air diluted concentrations presented. The detectability of the odorants was studied using a procedure related to signal detection theory; the perceived odour intensity was measured by the method of direct magnitude estimation. The detectability and psychophysical functions were constructed, and a rationale was developed for anchoring the psychophysical functions from the twelve odorants investigated. Over the period of investigation the exponents of the psychophysical functions obtained for odorants sampled from the same poultry house were very similar. Differences in this respect between odorants of different poultry houses appeared to be large. However, it was observed that the estimated intensities of undiluted odorants obtained from the same poultry house varied to some extent. These findings were discussed from a methodological point of view.