Electronic nose for the continuous measurement of odour concentration at emissions: instrument development, training and application

The presence of odour in ambient air is nowadays recognized as an environmental stressor that negatively affects the quality of life (Blanes-Vidal et al., 2012). In order to evaluate odour exposure at receptors, several methods can be applied. Different regulations provide to use dispersion modelling to simulate how odour disperses into the atmosphere, and consequently to calculate hourly ground odour concentration values in the simulation spacetime domain (Cusano et al., 2010). Given that a detailed characterization of emissions over time would require frequently repeated olfactometric tests, thus resulting in a very expensive (in terms of money and time) approach, emission data employed as model inputs are usually represented by averaged odour emission rate values. This approach may provide a good description of the average odour impact, but doesn’t take account of fluctuations that are typical of some emission typologies (Isaac-Ho Tin Noe et al., 2010). This study discusses the possibility of installing an electronic nose directly at an emission, in order to measure odour concentration continuously and therefore to obtain data that could be possibly used as real-time inputs for dispersion models as well as hourly data to use instead of averaged values. Such an application requires the development of a specific instrument, as well as a specific training. An EOS 507 electronic nose, developed in collaboration with Sacmi s.c. and Progress S.r.l., was used to evaluate the possibility to monitor the odour concentration at the emission of a plant for hospital waste treatment. Laboratory tests were conducted to evaluate the electronic nose capability of quantifying odour concentration: samples containing pure compounds and mixtures were tested at different concentrations, as well as real samples collected directly from the odour source.