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Odour Detection Methods: Olfactometry and Chemical Sensors
Department of Chemistry, University of Bari, via E.Orabona 4, 70126 Bari, Italy
Brindisi Technical Unit for Technologies of Materials, ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, P.O. Box 51 Br-4, I-72100 Brindisi, Italy
* Author to whom correspondence should be addressed.
Received: 28 April 2011; in revised form: 5 May 2011 / Accepted: 5 May 2011 / Published: 16 May 2011
Abstract: The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc.) and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality); this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants) as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses) are then described, focusing on their better performances for environmental analysis. Odour emission monitoring carried out through both the techniques is finally reviewed in order to show the complementary responses of human and instrumental sensing.
Keywords: odour detection; odour concentration; sensory methods; dynamic olfactometry; electronic nose; sensors; sampling methods; GC-O
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Brattoli, M.; De Gennaro, G.; De Pinto, V.; Demarinis Loiotile, A.; Lovascio, S.; Penza, M. Odour Detection Methods: Olfactometry and Chemical Sensors. Sensors 2011, 11, 5290-5322.
Brattoli M, De Gennaro G, De Pinto V, Demarinis Loiotile A, Lovascio S, Penza M. Odour Detection Methods: Olfactometry and Chemical Sensors. Sensors. 2011; 11(5):5290-5322.
Brattoli, Magda; De Gennaro, Gianluigi; De Pinto, Valentina; Demarinis Loiotile, Annamaria; Lovascio, Sara; Penza, Michele. 2011. "Odour Detection Methods: Olfactometry and Chemical Sensors." Sensors 11, no. 5: 5290-5322.