FIDOL factors that represent five dimensions (Frequency, Intensity, Duration, Offensiveness and Location) are tools for odour impact assessment. If the four factors (F, I, D, O) are clearly identified parameters, the fifth one (L) can be interpreted in different ways. Some recent communications are based on FIDOR (R as Receptor) or FIDOS (S as Sensitivity) to integrate larger impact than only the location (L). For location, the perception is not the same at work place or in a residential area, but the difference also depends on the considered period (workday, weekend or holidays) and also on sensitivity caused by tiredness or on any other “aggressive” perception (noise, very bad weather…). Therefore, two approaches are eligible: adding new dimensions (R and/or S) to obtain six/seven factors or considering the fifth one (L) as a multidimensional factor (LRS). All factors describe a characteristic of odour impact and for each of them; a scale has to be defined to give a value representing/describing its impact. Thus, what is the more acceptable and representative scale for each factor? After such a choice, the potential weight of each factor on the global perception is also a real question?Global odour perception is, in fact, subjective due to the interpretation of perceived smells in a context. Therefore, factors must integrate the subjectivity for all dimensions they represent. That means it could be interesting to keep the subjective feeling avoiding interference by objective external quantitative measurement like chemical or physical sensors (for example estimating exposure time or intensity based on pollution detection by sensors).