OCI Correlation Relationship

OCI is an abbreviation for Odour Concentration Intensity. Sometimes, it is called odour super-threshold. 

Odour intensity is the perceived psychophysical strength of an odour above its odour threshold. Typically, odour intensity doubles if chemical concentration triples.

OCI measurement follows the Germany VDI guideline (VDI 3882.1, 1992-10, Olfactometry: Determination of Odour Intensity).  In the DynaScent OCI method, a random presentation order has been implemented.   

The objective of the odour concentration-intensity measurement is to experimentally determine the relationship (Weber-Fechner). Normally, five dilution steps and a blank are presented randomly. The minimum dilution step is the level just above its odour concentration. The panellists sniff the diluted odour from the left cup and select one of seven odour intensity levels: no odour, very weak, weak, distinct, strong, very strong and extremely strong. As a result, the regression between odour intensity levels and the dilution ratios can be determined.

Reference:

Jiang, J., Coffey, P., and Toohey, B., Improvement of Odor Intensity Measurement Using Dynamic Olfactometry, Journal of Air and Waste Management Association, 56: 675 – 683, May, 2006

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