Artificial Olfaction in the 21^st Century

Abstract

The human olfactory system remains one of the most challenging biological systems to replicate. Humans use it without thinking, where it can equally offer protection from harm and bring enjoyment in equal measure. It is the system's ability to detect and analyze complex odors, without the need for specialized infra-structure, that is the envy of many scientists. The field of artificial olfaction has recruited and stimulated interdisciplinary research and commercial development for several applications that include malodor measurement, medical diagnostics, food and beverage quality, environment and security. Over the last century, innovative engineers and scientists have been focused on solving a range of problems associated with measurement and control of odor. The IEEE Sensors Journal has published Special Issues on olfaction in 2002 and 2012. Here we continue that coverage. In this article, we summarize early work in the 20 th Century that served as the foundation upon which we have been building our odormonitoring instrumental and measurement systems. We then examine the current state of the art that has been achieved over the last two decades as we have transitioned into the 21 st Century. Much has been accomplished, but great progress is needed in sensor technology, system design, product manufacture and performance standards. In the final section, we predict levels of performance and ubiquitous applications that will be realized during in the mid to late 21 st Century.

Classification of Two Volatiles Using an eNose Composed by an Array of 16 Single-Type Miniature Micro-Machined Metal-Oxide Gas Sensors

“…Covington et al [ 3 ] defined an eNose as an array of sensors that vary their selectivity according to the classes of chemical species analyzed. In general, this array is expected to include different types of sensors, which should have high sensitivity to a specific gas, rapid response time, a return to baseline levels, and high resistance to variable environmental conditions.…”

“…Covington et al [ 3 ] presented a comprehensive recent revision of the state of the art of the concept of artificial olfaction in the 21st century, analyzing the recent applications of artificial olfaction based on the use of an eNose and comparing alternative gas sensing technologies: chemooptical [ 6 ], electrochemical [ 7 ] and chemoresistive [ 8 ]. Chemooptical devices are expensive and have big size, electrochemical sensors need maintenance, and chemoresistive technology usually has fast response and does not require maintenance, although having higher power consumption.…”

“…According to Covington et al [ 3 ], the production of miniaturized silicon MOX gas sensors has been the most remarkable improvement of MOX gas sensors over the last 10 years because this miniaturization reduces the power consumption and the response time.…”

Carbon SH-SAW-Based Electronic Nose to Discriminate and Classify Sub-ppm NO2

“…One of the principal functions of these sensors is the monitoring of chemical compounds. It has been becoming increasingly challenging in several applications related to air quality assessment [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] and medical diagnostics [ 8 , 9 ]. These needs have led to the emergence of new generations of low cost, portable and reliable gas sensor devices with high potential discrimination among low concentrations of analytes of interest.…”

Drift in a Popular Metal Oxide Sensor Dataset Reveals Limitations for Gas Classification Benchmarks

“…Over the last 50 years, artificial olfaction has evolved from an almost niche field of study into a thriving interdisciplinary research area. Many use cases have been addressed, for example the detection of hazardous gases or pollutants [1], spoilage localization [2], mobile olfactory robotics [3], health monitoring [4] and medical screening [5]; and artificial olfaction is expected to address many more use cases in the future [6]. A key challenge in artificial olfaction is to identify a range of odorants at high specificity.…”