Sensitivity Analysis of Odour Exposure from Dispersion Modelling Exercises with Different Peak-to-mean Ratio

The odour impact assessment of an anonymized case study revealed occasionally conflicting results when utilizing two model systems, CALPUFF and LAPMOD, with different peak-to-mean ratio (PMR) configurations. Implementing a dynamic PMR with a shorter peak time showed more conservative evaluations in the near-field but resulted in opposite outcomes in the far-field. The choice of model and the approach employed to estimate PMR significantly affected the determination of separation distances and the protection level, highlighting the potential risk for inconsistent conclusions, particularly within regulatory contexts. Increased awareness is crucial for both practitioners and regulators on the consequences of a specific model configuration in odour impact assessments. Achieving consistency in modelling exercises and ensuring an adequate level of protection for sensible receptors remains challenging, highlighting the importance of a strong commitment to reproducibility for effectively quantify uncertainties in odour impact assessments.