Abstract
This study addresses the challenge of assessing odour impacts, which differ from conventional air pollutants due to their sensitivity to short-term peak exposures. Even brief odour events can cause disturbance, making high-end percentile concentrations more relevant than long-term averages. For this reason, it is crucial to estimate the odour emission flux at high temporal resolution, so that short-term emission peaks, more representative of potential odour nuisance, are properly captured. The research evaluates odour dispersion from a bituminous conglomerate plant located in a densely urbanized area using the CALPUFF dispersion model. The analysis focuses on how different temporal emission patterns influence odour impact at nearby receptors. Two emission sources associated with distinct production units are considered, and their impacts are assessed under two modelling scenarios: (i) a realistic discontinuous schedule with emissions during working hours, including a stochastic one-hour peak linked to loading activities; (ii) a simplified and intentionally conservative continuous 24-hour emission scenario, providing a coarse, upper-bound estimate rather than a refined representation of actual conditions. Results show substantial differences in predicted odour impacts between the scenarios. The findings emphasize that emission timing and temporal variability play a crucial role in odour dispersion, highlighting that overly conservative assumptions may not reflect real conditions and can misrepresent actual impacts.
