Abstract
Reliable estimation of odour emission rates is essential for environmental permitting and dispersion modelling. This study addresses the specific challenge of evaluating odour fluxes from industrial basins and inspection pits that are covered by metal grates, which prevent the direct application of conventional sampling hoods such as wind tunnels or flux chambers. In such configurations, the physical obstruction of the emitting surface makes direct sampling at the liquid–air interface unfeasible, thereby limiting the applicability of standard methodologies typically recommended for area sources. To overcome these constraints, this study proposes an alternative methodological framework that integrates in situ field measurements with theoretical estimations of mass transfer processes. The approach combines measurements of odour concentration within the air layer above the covered source with parameterizations of mass transfer coefficients derived from established formulations in the scientific literature and expressed as functions of meteorological and micrometeorological variables. The proposed method was evaluated through comparison with alternative approaches, including a headspace-based method coupled with mass transfer correlations and wind tunnel measurements performed on liquid samples. The comparison, carried out in terms of specific odour emission rates, showed consistent results between the in situ-based method and the wind tunnel approach, while the headspace-based method yielded lower SOER estimates. Notably, the proposed approach is the only one based on direct sampling performed under real field conditions, allowing emission estimates to be derived without the need for liquid collection or laboratory reconstruction of the source. This practical advantage, combined with the observed consistency with wind tunnel results, supports its applicability for the assessment of geometrically constrained sources under real operating conditions.
