Estimation of Odour Detection Threshold Values For Selected Pure Compounds

This paper will provide new odour detection thresholds values that were developed for twenty-four pure compounds. Until most recently, there have only been a few publications with odour detection threshold values for pure chemicals, and most of these publications have not been updated and are therefore not current.Beginning from 1960 to 1990, different methodologies for determining thresholds were used. With time, our community has acknowledged that these past used procedures were not correct due to odour losses during actual evaluations. In the 1960 and the 1970’s, a common approach for determining odour threshold values was to smell a syringe filled with different chemical concentrations. This of course, was highly inaccurate, and did not rely on scientific analysis, but rather estimation. In the late 1970’s when dynamic olfactometry was introduced, the new odour detection thresholds values were then developed based on a new dynamic olfactometry method. However, at that time it was unknown that the flows at the sniffing ports play an important role in the evaluation process and therefore in the final results. In the late 1980’s, flows at sniffing ports of the olfactometer were too low and the actual samples were diluted with ambient air during evaluations resulting in much higher odour detection threshold values (actual lower results).With a newly developed European standard in 2003, and armed with knowledge that sniffing flows during evaluations should be around 20 L/min in order not to dilute the sample during analysis, there is a need for an update on the odour detection threshold values.This study is based on the evaluation of twenty-four compounds for odour detection threshold values. These values were compared with those previously developed for those chemicals or any other available resources. Odour offensiveness and complaint threshold values are also determined for these compounds.