Source emission odor measurement by a dynamic forced-choice triangle olfactometer.

Abstract

Current odor emission control regulations specify a syringe dilution technique to determine odor concentration level of exhaust stack emissions. This procedure in practice is cumbersome, slow, and subject to improvisations. Further, there is no satisfactory provision to check reliability of positive-negative responses of panel. An approach is desired where the diluted odor sample is presented to the panel for discrimination from samples of non-odorous air and results can be related to statistically significant confidence levels.An olfactometer based upon forced-choice triangle statistical design was designed and constructed. One diluted odor sample and two non-odorous air blanks are presented dynamically at each dilution level. Each panelist is required to judge which of three ports is odorous and to signal a choice. The three ports are arranged in a circular symmetrical pattern to achieve a double-blind sample presentation since neither panelists nor panel leader know the correct choice until after the j...