Real-time Odour Dispersion Modelling for Industrial Sites Application: State of the Art and Future Perspectives

In the field of odour impact assessments resulting from industrial activities, the use of atmospheric dispersion models appears to be crucial. These mathematical tools are able to estimate the ambient air odour concentration at the receptors nearby a plant, as indicated in some guidelines and laws. Generally, the odour concentration is evaluated through emission olfactometry monitoring, and subsequently, based on the dispersion modelling software, impact maps are created at specific percentiles (odour concentrations that are reached for a certain number of hours a year). However, in this way, it is not possible to know the specific odour event as it occurs; therefore, it would be ideal to have a real-time estimation of the odour fallout in the plant's surroundings. Currently, there exist some scientific papers and several commercial which propose some kind of real-time odour monitoring. Overall, these tools aim to monitor the odour events that occur on-site in real-time and to model atmospheric dispersion. The present work seeks to summarise what is currently available for real-time estimation of odour emission and dispersion, with the purpose of highlighting the potential, the eventual limitations, and the principal aspects to be studied and investigated. These considerations may help to develop a newer approach in order to stimulate the research towards the highest possible accuracy of these systems

DEVELOPMENT OF A SIMULATION TOOL TO EVALUATE THE APPLICABILITY OF THE GRADIENT METHOD FOR THE ESTIMATION OF ODOUR EMISSION FLUXES

Micrometeorological methods are commonly used in agro-meteorology for the estimation of biogenic emissions. Despite being often mentioned, their practical application for indirect estimation of odour emission rates is extremely rare. Among the existing methods, this work focused on the Gradient Method and the main objective was to identify the technical characteristics required for analysers to be used for the estimation of odour fluxes. This valuation was carried out through the implementation of a flexible simulation tool which, by using reference odour fluxes and real meteorological data measured during the year 2015 by an ultrasonic anemometer (Tor Vergata, Rome), made it possible to recreate the functioning of a measuring device, and thus to assess a priori the possibility of applying these methods. For this purpose, the absolute concentration and concentration difference at the measurement point were determined in order to assess the limits of detection and resolution required by the odour analyser. The results showed that for an odour flux of 1 ou E /m 2 /s, if 50 ou E /m 3 is taken as the lower resolution limit for odour concentration measurements, the percent data that could hypothetically result above this limit would be 33.3% if considering two measurement heights of 0.5 and 3.5 , and 44.3% if considering two measurement heights of 0.5 . Similar considerations can be made based on analysis of the absolute concentration measured at the two sampling heights. Moreover, the influence of atmospheric stability on the data above the background odour has been investigated: the measurement of the concentration gradient as well as of the absolute concentration, regardless of the chosen measurement heights, is only feasible under the conditions described by categories D and F. In conclusion, the gradient method represents an attractive and potentially applicable alternative for estimating odour emissions, since the developed simulation tool has demonstrated to be suitable to evaluate the conditions of applicability of the method as a function of specific emission and meteorological conditions. However, the effective direct applicability to the odour concentration requires further study and experimental campaigns