This paper provides updated odour detection threshold values (ODTV) for fifty-two (52) pure compounds. In 2014, the first updated odour threshold data (Bokowa, 2014) was presented for twenty-four (24) pure compounds. Over the past eight (8) years, more studies were performed, and another twenty-eight (28) compounds were chosen for odour threshold studies. 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.
Between 1960 and 1990, different methodologies for determining odour thresholds were used. In the 1960 and the 1970s, the common approach for defining ODTV was to determine the odour threshold value by smelling a syringe filled with different chemical concentrations. This, of course, was highly inaccurate and did not rely on scientific analysis, but rather on estimation. In the late 1970s when dynamic olfactometry was introduced, new ODTVs were developed based on the dynamic olfactometry method. However, at this time, it was unknown that the flows from the sniffing ports play an important role in the evaluation process, and, therefore, in the final results. In the late 1980s, flows at the sniffing ports of the olfactometer were too low, and actual samples were diluted with ambient air during evaluations resulting in much higher odour detection threshold values (actual lower results). In 2003 with a newly developed European Standard, and armed with the knowledge that sniffing flows during evaluations should be around 20 L/min in order not to dilute the sample during analysis, there was a need to update the ODTV. This study is based on the evaluation of fifty-two 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.
Keywords: Odour, odour detection threshold value, olfactometry, odour evaluation, odour offensiveness threshold value, odour complaint threshold value, panelist, pure comp