Abstract

It is widely recognizing that the regulation of odor pollution must be done based on the evaluation for the results of sensory measurement, instead of the concentrations for individual 8 odorants as defined by the offensive odor control law and the triangular odor bag method has used in many local governments.
However, this method have several unsolved problems on measuring procedure and treatment of the obtained date remaining, and those problems have been the obstacle to the adaptation of this method as the legal measuring method of odor of Japan EPA, So, we reported the investigated results on the method for environmental odor as previous paper.
In this paper, the precision of method for odor at the exit of chimney are considered and the results obtained are as follows,
1) As a large amount of scatter for measured value is caused by the accidental hit on the present triangular choise test, it is nessesary to reduce the probability of occurence for accidental hit on the triangular choise of panel, by defining one correct answer with two or three hit.
2) It is seemed that the present 3-fold dilution series of sample odor to be given for the panels is most reasonable on the practical use.
3) In the present method, the number of panel is uniformely limited to 6 and this can not always brought the results with high accuracy. Therefor, it have to select from 6 to 10, based on the consideration for the quality of sample odor.
4) The evaluation method for the odor concentration value must be investigate under the setting of confidence intervals.