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.94 tables II & III, p.95 tables IV & V
||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.94 right column 2nd paragraph:"As a group, compounds with the sulfur atom in their structure have the lowest thresholds of the compounds evaluated (Table II). All the sulfides with the exception of carbon disulfide and sulfur dioxide have threshold concentrations at the parts per billion level." P.94 right column 4th paragraph:"Of the 53 odorant chemicals evaluated, trimethyl amine exhibited the lowest threshold (0.00021 ppm). Dimethyl formamide is recognizable at 100 ppm. The nitrogen-containing compounds indicate the wide range of threshold concentrations that can occur (Table III)." P.94 right column 5th paragraph:"Table IV lists the odor thresholds of oxygenated compounds according to chemical class. Extent of oxidation of the ethanol series (ethanol, acetaldehyde, acetic acid) does not appear to have an affect on the odor threshold trend. One might expect a lower threshold as the oxidation state is increased. Chloral (trichlorinated analog of acetaldehyde) does have a substantially lower threshold (0.047 ppm) than
acetaldehyde. Considering other chlorine-containing compounds studied, it is not possible to make a generalization as to the effect of chlorination on the odor threshold." P.94 right column bottom paragraph:"The presence of unsaturation in an odorant chemical is not associated with low threshold concentrations (Table V). Ethyl acrylate and methyl methacrylate are isomeric, however, the threshold concentrations are quite different. The odor descriptions do differ (see Table I BNID 112190). This disparity points up the difficulty of making extended generalizations pertaining to the odor threshold based on similar chemical structures."