Dispersion Models

Dispersion models are mathematical simulations that allow describing the odors and pollutants dispersion (NOx, SOx, CO, PM10 ...) in the territory surrounding the production facilitiy. 



Ministerial Decree no. 261 dated 01/10/2002 "Regulation containing thetechnical directives for the preliminary assessment of ambient air quality, thecriteria for the preparation of the plan and programs referred to in articles 8and 9 of Legislative Decree 4 August 1999 , n. 351" identifies thedispersion models as a useful tool for the following purposes:

  • "To obtain concentration ranges also in portions of territory where there are no measurement stations, or to extend the spatial representativeness of the measure itself; 
  • Obtain information on the relationships between emissions and inputs (source and receptor matrixes), thus discriminating between the contributions of the various sources;
  • Eevaluate the impact of pollutants that the monitoring network is not measuring; 
  • Study hypothetical scenarios of alternative emissions compared to current or past framework ". 

Odor dispersion modeling allows quantifying the osmogenic impact of a plant on the surrounding territory. It is based on olfactometric data, meteorological data and territory orography. It provides a precise indication of the olfactory impact caused by a plant in the surrounding areas. 

The main steps in the construction of a dispersion model are the following:

  • Identification of emission sources;
  • Collection of meteorological data (for example from official control units), as well as data on orography and land use;
  • Simulation of odors and / or pollutants fallout;


Theuse of dispersion models to evaluate odor impact on sensitive receptors isrecommended in Instructions for theapplication of article 272-bis of Decree-Law 152/2006 regarding odor emissionsin plants and premises, edited by M.A.S.E

Dispersion models are the only tool that allows to make "predictive" assessments on the potential fallout of pollutants and smells on the territory, before the realization of the plant itself

The main applications of dispersion modeling are the following:

  • Forecasting assessments of the impact of atmospheric emissions of odors and pollutants for authorization purposes;
  • Evaluation of the impact of atmospheric emissions starting from the results obtained through olfactometric sampling carried out on emission sources.

This article is about a study case on models validation using the odor field inspection method.  

LOD: Laboratorio Olfattometria Dinamica

Spin-off dell’Università degli Studi di Udine