When it comes to assessing off-site odours from a facility, the use of a dispersion model is almost always mandatory. There are several models used for odour and there is always a dilemma of which model is better. However, each model has different limitations and errors and various other factors contributing to the final results, therefore it is almost unknown if predicted by model off- site odour concentrations are true values or if they are close to the real values. This paper introduces the technique for verification of odour predictions by dispersion modelling. Simply, ambient sampling on the days of source sampling performed at the sensitive receptors verifies if the model was right. However, some precautions should be followed. This paper is based on several studies performed in Ontario, Canada when ambient sampling was performed at the same time as source sampling and different models were used to predict off-site odour. The correlation between measured and predicted values is presented in this paper.
