Table - link ppm volume
||Human Homo sapiens
||Gregory Leonardos , David Kendall & Nancy Barnard (1969) Odor Threshold Determinations of 53 Odorant Chemicals, Journal of the Air Pollution Control Association, 19:2, 91-95, DOI: 10.1080/00022470.1969.10466465 link p.95 tables VI & VII
||Abstract:"In order to assist in assessing potential odor problems arising from chemical manufacturing operations, the odor thresholds of 53 commercially important odorant chemicals have been determined using a standardized and defined procedure… The odorants were presented to a trained odor panel in a static air system utilizing a low odor background air as the dilution medium. The odor threshold is defined as the first concentration at which all panel members can recognize the odor. The effect of chemical purity has been determined by measuring the odor threshold of materials representing different modes of manufacture or after purification by gas chromatographic procedures."
||P.95 middle column 2nd paragraph:"The effect of substitution on the benzene ring also produces a wide variation in odor thresholds Table VI.
A single methylation of the benzene ring (toluene) lowers the threshold one concentration step. Further methylation (p-xylene) succeeds in lowering the odor threshold by an order of magnitude. The —CH2Cl group (benzyl chloride) produces an odor threshold that is 100 times lower than benzene. The only generalization possible with benzenoid-type materials is that substitution on the ring reduces the odor threshold by as much as a thousandfold depending on the nature of the group added." P.95 middle column 4th paragraph:"Odor thresholds of samples purified by gas liquid chromatography show slight differences, if any, from the starting material. With tolylene diisocyanate, the prime effect of the purification appears to eliminate or reduce subsidiary odor character notes and leaves a sharper odor impression of the prime odor character note. In this case, purification did not affect the recognition threshold. Table VII lists the odor thresholds of chemicals before and after purification."