Experimental Investigations on the Combined Actions of Components Mixed in Odorous Gas

Abstract

Odor problems are generally caused by many kinds of malodorous substances at low concentration. In practice, it is extremely difficult to carry out a complete analysis of odor causing components by means of any instrumental analytical methods. For this reason, there is a great demand for a more reliable odor evaluation method based on sensory measurement. The present investigation was therefore carried out to solve the problems involved in conventional methods for sensory measurement and evaluation, and to establish a method which might be effectively utilized for odor problems. Using eight odorants, the co-operative action of the combined components in mixed odors are discussed and the results are as follows. (1) The interaction between the combined components of the duplex complex odor influences the intensity of mixed odors. It also varies with the composition of the constituents and the ratio of the dilution/threshold numbers for the constituents. (2) In some complex odors, the combined actions were found to change from a potentiality to a cancellation with a change of the dilution/threshold number.