Have you heard of the electronic nose?

The electronic nose is intended to replace the olfactometric measurement method, and it has been extensively researched and developed over recent decades.

The aim of this development has been to create an "artificial nose" or "electronic nose" that determines the magnitude of an odour based on the operating principle of the human nose.

How does electronic "smelling" work?

Each of the various gas-sensing microanalysers built into the "measuring instrument" sits behind its own selective membrane and only detects and measures certain components of the odour mixture. The measurement result is obtained by combining the signals produced by the individual analysers. In most cases, the heart of the device is a microprocessor, into which the gas sensors are also integrated and which also evaluates the measurement.

An electronic nose (E-nose, artificial nose) consists of sensors with different characteristics and selectivities (chemical, gas), a signal processing and data acquisition system, and some form of pattern recognition algorithm.

It works on the principle that a given odour is defined by a large number of different compounds. The chemical sensor array produces a corresponding series of response signals, each sensor weighted by its own selectivity factors, determined by the combination of compounds characteristic of the given odour.

Human smell remains indispensable

However, the human nose is indispensable in calibrating and training electronic noses, since parallel measurement results obtained by dynamic olfactometry are always used during calibration.

In practice, after proper olfactometric calibration, the electronic nose is well suited to "alarm" use: installed near process odour sources or at the plant boundary, it can signal excessively increased odour emissions.

Although the selectivity of individual sensors and the specificity of their response signals are weak, taken together the response signals carry significant information, which can make it possible to distinguish between odours.

The human nose essentially treats multiple odour components as a mixture rather than separating them, whereas the electronic nose is built from an array of sensors that - with appropriate pattern recognition - can identify both simple and complex odours.

What is an e-nose good for?

It can be mounted on a drone or used alongside one, so it can help survey large sites, as well as areas where hazardous gases, vapours, other harmful substances or disturbing odours are present, since direct contact with them can be avoided during investigation, significantly reducing the health risk to specialists.

Artificial intelligence can therefore help us recognise and detect the various components of different disturbing odours.