An electronic nose for quantitative determination of gas concentrations

The practical application of human nose for fragrance recognition is severely limited by the fact that our sense of smell is subjective and gets tired easily. Consequently, there is considerable need for an instrument that can be a substitution of the human sense of smell. Electronic nose devices from the mid 1980s are used in growing number of applications. They comprise an array of several electrochemical gas sensors with partial specificity and a pattern recognition algorithms. Most of such systems, however, is only used for qualitative measurements. In this article usage of such system in quantitative determination of gas concentration is demonstrated. Electronic nose consist of a sensor array with eight commercially available Taguchi type gas sensor. Performance of three different pattern recognition algorithms is compared, namely artificial neural network, partial least squares regression and support vector machine regression. The electronic nose is used for ammonia and nitrogen dioxide concentration determination.