The Odor Characterizations and Reproductions in Machine Olfactions: A Review

Abstract

Machine olfaction is a novel technology and has been developed for many years. The electronic nose with an array of gas sensors, a crucial application form of the machine olfaction, is capable of sensing not only odorous compounds, but also odorless chemicals. Because of its fast response, mobility and easy of use, the electronic nose has been applied to scientific and commercial uses such as environment monitoring and food processing inspection. Additionally, odor characterization and reproduction are the two novel parts of machine olfaction, which extend the field of machine olfaction. Odor characterization is the technique that characterizes odorants as some form of general odor information. At present, there have already been odor characterizations by means of the electronic nose. Odor reproduction is the technique that re-produces an odor by some form of general odor information and displays the odor by the olfactory display. It enhances the human ability of controlling odors just as the control of light and voice. In analogy to visual and auditory display technologies, is it possible that the olfactory display will be used in our daily life? There have already been some efforts toward odor reproduction and olfactory displays.

Odour-sensitive passenger comfort in small aircraft cabins

“…Furthermore, an odour-controlling system should be introduced, capable of creating and dissipating multiple types of ingested odours through the ventilation system. Proper mechanical odour sensors [2] should be placed appropriately in proximity to the passengers' noses to capture odours similar to the human olfactory system. Additionally, odour sources will be placed in the test rig seats to assess the breathing impact of others on the odour experience of an individual.…”

“…Odour sensors are neither simple nor inexpensive equipment. Despite that the concept of the machine olfactory system goes back to 1961, it remains very complex, mainly focuses on gas detection, and consists of various compartments, such as the sampler, the computing system, the media -where the data is stored-and the representer that can reproduce the stored odours [2]. On the contrary, there is limited research trying to understand the mechanisms that the human olfactory system detects and discriminates odours [3], and scientists can't yet clearly reach a consensus on whether there is a global methodology that can be applied to that matter.…”

An experimental paradigm for studying EEG correlates of olfactory discrimination

“…Yet, the settings proposed here are more natural, comfortable and controlled compared to both manual delivery of odors ( Saha et al, 2013 ; Aydemir, 2017 ; Abbasi et al, 2019 ; Zhang et al, 2021 ; Ezzatdoost et al, 2020 ) and using an olfactometer attached to the nostrils ( Murphy et al, 2000 ; Rombaux et al, 2006 ; Invitto and Mazzatenta, 2019 ). While the field has been growing of olfactory displays that achieve the stable perception of odors in a naturalistic setup ( Nakamoto et al, 2012 ; Wen et al, 2018 , 2019 ), only a few EEG studies employed such displays. Amores et al (2018) conducted a study with a wearable olfactory display (an olfactory necklace) and recorded EEG data with a low-cost EEG headband.…”

Odor Characteristics and Concentration of Malodorous Chemical Compounds Emitted from a Combined Sewer System in Korea

“…In general, a variety of methods are used to measure odors such as instrument analyzers like gas chromatographs, sensory devices like dynamic olfactometer, odor sensors or gas detection tubes. Additionally, new techniques for accurately evaluating odors have still been continuously developed [24][25][26][27][28][29][30][31][32][33].…”