Discrimination of Forane 134a and carbon dioxide concentrations in an air conditioned atmosphere with an electronic nose: influence of the relative humidity

Nowadays, lots of efforts are done all over the world to protect the atmosp here from the greenhouse effects. In the field of smart sensors, new applic ations called electronic noses are developed and used for environmental air quality control. We present here such an application based on a TGS sensor array for the detection of two main gases inducing green house effects: a new refrigerant type gas and carbon dioxide (CO2). In this paper. we propose to study the influence of the relative humidity r ate on the quantification of these gases and the ability of our system to s uccessfully identify the concentration of unknown test samples. After summa rising the experimental system used for the accurate characterisation of th e chosen sensor array and giving the obtained experimental results, we pres ent and compare the gas quantification results obtained with principal comp onent analysis (PCA) and discriminant factorial analysis (DFA). We prove th at the presence of humidity has a great influence on the sensor responses a nd the gas concentration discrimination in an air conditioned atmosphere an d we show that DFA offers the best results for this quantification even tha t PCA is the more used method in the literature. (C) 2001 Elsevier Science B.V. All rights reserved.