Odour Intensity: It is the perceived strength of an odour above its threshold. It is determined by an odour panel and is described in categories which progress from “Not perceptible”; “Very Weak”; “Weak”; “Distinct”; “Strong”; “Very Strong” to “Extremely Strong”.
Hedonic Tone: It is the degree to which an odour is perceived as pleasant or unpleasant. Such perceptions differ widely from person to person and are strongly influenced by previous experiences and emotions at the time the hedonic tone is evaluated.
Odour Character: It is basically what the odour smells like. It allows one to distinguish between different odours. For example, ammonia gas has a pungent and irritating smell. The character of an odour may change with dilution.
