An electronic nose based on fuzzy logic to the environmental monitoring of the industrial plants

Air quality is becoming the reference parameter in the industrialized Countries for both the social significance in terms of quality of life itself, and the scientific interest in the development of apparatuses and methodologies addressed to its improvement up to the desired standards. Odours are one of the major issues in the management of industrial plants for the negative impacts they may have on the population exposed. Therefore, odours must be identified, characterized and measured, and new techniques are currently proposed and implemented to control their emissions. Objective of the current investigation is to develop a methodology to measure odour concentration in the environment using a novel prototype of electronic nose (e.nose) system, equipped with metal-oxide based gas sensors which are sensitive to a wide range of volatile gases. However, given an industrial process, sensitivity of the relevant sensors spreads over a wide range, as much as specificity. Therefore, it is mandatory to select the most appropriate sensors for a particular activity/process to an accurate estimation of odour concentration. It is also been reported in literature that if the number of sensors is large, the discrimination indices in the analysis of the main components are generally poor, whereas better discrimination indices are obtained when the number of sensors is reduced to 4–6. Fuzzy logic is an important tool used to manage a significant amount of environmental data. This work reports for the first time the application of fuzzy logic tools in the architecture of the e.nose for the measurement of environmental odour. The study describes a methodology for the characterization of the odour concentration emitted by different industrial activities using a novel prototype of e.nose with an architecture based on fuzzy logic, with the aim of measuring the odour in a faster and more efficient way. The work shows the correlation between concentrations of the odour emissions, characterized by dynamic olfactometry according to EN13725:2003, and real time measurements obtained by the novel e.nose.